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Publication
Journal: Journal of Clinical Endocrinology and Metabolism
November/4/1998
Abstract
Adrenarche is the increased adrenal production of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) that occurs during the prepubertal period. To date, the exact mechanism initiating adrenarche is unknown, although many factors have been postulated. In the present study, we examined the hypothesis that alterations in intra-adrenal expression of 3beta-hydroxysteroid dehydrogenase (3betaHSD) or 21-hydroxylase (CYP21) within the inner reticularis zone leads to the increased production of 19-carbon (C19) steroids. After conversion of cholesterol to pregnenolone, 17alpha-hydroxylase/17,20-lyase (CYP17) can metabolize pregnenolone through to DHEA. The enzyme 3betaHSD competes for substrate with CYP17 and effectively removes steroid precursor from the pathway leading to DHEA. On the other hand, deficiency in CYP21 expression is known to cause excessive production of adrenal C19 steroids, suggesting that CYP21 could play a role in adrenarche. Thus, a decrease in 3betaHSD or CYP21 expression would allow substrate to flow toward the synthesis of DHEA. To determine whether adrenarche results from a decreased expression of 3betaHSD or CYP21 in the reticularis, immunohistochemical localization of 3betaHSD and CYP21 was performed, and staining intensities compared using adrenal glands from children ages 4 months to 4 yr (n = 12), ages 5-7 yr (n = 9), ages 8-13 yr (n = 9), and adults ages 25-56 yr (n = 8). There were no differences in the zonal expression of CYP21. No difference in 3betaHSD staining was observed between the glomerulosa and fasciculata from any age group. However, children age 8 yr and older show a significant decrease in 3betaHSD expression in reticularis as compared with the fasciculata. No significant difference was noted for 3betaHSD levels between the fasciculata and reticularis for children age 7 yr or younger. The level of 3betaHSD expression in the reticularis continued to decrease in the adult adrenals examined. These findings suggest that as children mature there is a decreased level of 3betaHSD in the adrenal reticularis that may contribute to the increased production of DHEA and DHEAS seen during adrenarche.
Publication
Journal: Endocrinology
December/26/1991
Abstract
Administration of dehydroepiandrosterone (DHEA) appears to have physiological effects opposing those of glucocorticoids in several animal models. Recently, immunomodulatory effects of treatment with DHEA have been described. This paper reports the effects of DHEA treatment on splenocyte blastogenic responses as well as thymic and spleen weights in C3H/HeN mice. Pretreatment of mice with sc DHEA (60 mg/kg.day) for 3 days in vivo antagonized the profound suppression of in vitro blastogenic responses seen in T- and B-lymphocytes after a single injection of dexamethasone (DEX; 60 mg/kg). Pretreatment with DHEA also significantly reduced dexamethasone-induced thymic and splenic atrophy. Splenic lymphocytes from DHEA-treated mice were markedly more resistant to in in vitro suppression of blastogenesis by DEX at 10(-6)-10(-8) M compared to lymphocytes from control mice. However, DHEA added to lymphocyte cultures in vitro over a concentration range from 10(-7)-10(-8) M failed to protect against suppression of mitogenic responses caused by addition of DEX to cultures. In summary, DHEA given in vivo antagonizes the suppressive actions of DEX on lymphoid target tissues in mice.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
June/16/1983
Abstract
Plasma levels of dehydroepiandrosterone sulfate (DHAS) were measured in 513 normal full term newborns, infants, children, adolescents, and adults and the results were expressed in micrograms per dl. In infancy and childhood, DHAS levels were similar in both sexes. In 74 neonates, mixed cord blood mean values /+- SD were 134.6 +/- 64. During the first day of life, plasma DHAS levels were 140 +/- 125 in 33 neonates. During the first month of life, DHAS decreased drastically, then more progressively until the 6th month of life. Between 1-6 months of age, mean levels were 5.9 +/- 4.7 in 40 children. DHAS was very low between 1-6 yr of life (2.3 +/- 1.6) and rose abruptly at the 7th year of life. Thereafter, DHAS continued to increase correlatively with age and pubertal stages in both sexes, a further increase after age 16 or pubertal stage P5 was noted only in male subjects. In adults, DHAS was significantly higher in male (224 +/- 93) than in female (138.3 +/- 51) subjects. DHAS levels were compared to those of dehydroepiandrosterone; at two periods of life, early infancy and adulthood, their patterns differed. After long term hCG stimulation, DHAS increased significantly in 45 normal prepubertal boys and in 2 boys with adrenal insufficiency. These data would suggest a direct testicular production of DHAS.
Publication
Journal: Drug Metabolism and Disposition
August/3/2006
Abstract
Flavonoids are a class of polyphenolic compounds widely present in the diet and herbal products. The interactions of flavonoids with some major efflux transporters [e.g., P-glycoprotein, multidrug resistance-associated protein 1 (MRP1), and breast cancer resistance protein] have been reported; however, their interactions with uptake transporters are largely unknown. Organic anion-transporting polypeptide OATP1B1 is a liver-specific uptake transporter important in hepatic drug disposition. Our objective was to evaluate the effects of 20 naturally occurring flavonoids, and some of their corresponding glycosides, on the uptake of [3H]dehydroepiandrosterone sulfate (DHEAS) in OATP1B1-expressing and OATP1B1-negative HeLa cells. Many of the tested flavonoids (including biochanin A, genistein, and epigallocatechin-3-gallate) significantly inhibited [3H]DHEAS uptake in a concentration-dependent manner in OATP1B1-expressing cells, with biochanin A being one of the most potent inhibitors with an IC50 of 11.3 +/- 3.22 microM. The flavonoids had negligible or small effects in OATP1B1-negative cells. Four of the eight pairs of tested flavonoids and their glycosides, namely, genistein/genistin, diosmetin/diosmin, epigallocatechin/epigallocatechin-3-gallate, and quercetin/rutin, exhibited distinct effects on [3H]DHEAS uptake. For example, genistin did not inhibit DHEAS uptake, whereas genistein did, and rutin stimulated uptake, whereas quercetin had no effect. [3H]Biochanin A uptake was similar in OATP1B1-expressing and OATP1B1-negative cells, suggesting that it is not a substrate for OATP1B1. A kinetic study revealed that biochanin A inhibited [3H]DHEAS uptake in a noncompetitive manner, with a Ki of 10.2 +/- 1.89 microM. Taken together, these results indicate that flavonoids are a novel class of OATP1B1 modulators, suggesting the potential for diet-drug interactions.
Publication
Journal: Endocrinology
March/22/1999
Abstract
An important source of androgens in the human prostate are those synthesized locally from the inactive adrenal precursor dehydroepiandrosterone (DHEA) and its sulfated derivative DHEA-S. Three beta-HSD (hydroxysteroid dehydrogenase) converts DHEA into androstenedione (4-dione), whereas type 5 17beta-HSD catalyzes the reduction of 4-dione into testosterone in the human prostate and other peripheral intracrine tissues. In the present study, we have used two complementary approaches, namely in situ hybridization and immunocytochemistry, to identify the cells that contain the type 5 17beta-HSD messenger RNA and enzyme in human benign prostatic hyperplasia (BPH). Localization of 3beta-HSD and of the androgen receptor (AR) was also investigated by immunostaining in the same tissue. To find out whether there are any differences between BPH and normal prostate tissue, the localization of type 5 17beta-HSD was reexamined by immunocytochemistry in the normal human prostate samples and also in normal prostate epithelial cell line (PrEC). The in situ hybridization results obtained with a tritiated uridine triphosphate (3H-UTP)-labeled type 5 17beta-HSD riboprobe are in agreement with the immunostaining data obtained with a specific antibody to the enzyme. The immunostaining results obtained from normal prostate tissue and BPH were found to be similar. Thus, in the glandular epithelium, basal cells highly express the messenger RNA and the enzyme, whereas luminal cells show a much lower and variable level of expression. In the stroma and walls of blood vessels, fibroblasts and the endothelial cells lining the blood vessels show positive staining. Similar results are observed when the cellular distribution of 3beta-HSD is investigated. AR immunoreactivity, however, shows a different distribution because, in the epithelium, most of the nuclei of basal cells are negative, whereas the majority of nuclei of the luminal cells show positive staining. A strong reaction for AR is also found in most stromal cell nuclei and in the nuclei of most endothelial cells, as well as in some other cells of the walls of blood vessels. In conclusion, human type 5 17beta-HSD, as well as 3beta-HSD, are highly expressed, not only in the basal epithelial cells and stromal fibroblasts but also in the endothelial cells and fibroblasts of the blood vessels. AR, on the other hand, is highly expressed in the luminal cells. The present data suggest that DHEA is transformed in the basal cells of the glandular epithelium into 4-dione by 3beta-HSD and then into testosterone by type 5 17beta-HSD, whereas dihydrotestosterone is synthesized in the luminal cells after diffusion of testosterone from the underlying layer of basal cells. The potential role of androgen formation and action in blood vessels is unknown and opens new avenues of investigation for a better understanding of the multiple roles of androgens.
Publication
Journal: Arteriosclerosis, Thrombosis, and Vascular Biology
April/30/1997
Abstract
Although sex hormones appear to be importantly involved in the development of coronary heart disease, apparently no study has yet reported an alteration in an endogenous sex hormone level in relation to coronary heart disease in women. In an attempt to determine whether any sex hormone abnormality might be a factor in the development of myocardial infarction in women, estradiol and testosterone, as well as sex hormone-binding globulin, insulin, dehydroepiandrosterone sulfate, and risk factors for myocardial infarction, were measured in relation to the degree of coronary artery disease (CAD) in 60 postmenopausal women undergoing coronary angiography. In a multiple-regression analysis with the degree of CAD as the dependent variable and free testosterone (FT), estradiol, age, body mass index, systolic blood pressure, cholesterol, smoking, and insulin as independent variables in the model, only FT (P < .008) and cholesterol (P = .01) were significantly related to the degree of CAD, both positively. To exclude a possible confounding effect due to prior myocardial infarction, the multiple-regression analysis was repeated for the subgroup of 49 patients remaining after excluding the 11 patients who had ever had a myocardial infarction; again only FT (P < .04) and cholesterol (P = .05) were significantly related to the degree of CAD. Neither total testosterone in place of FT nor HDL cholesterol in place of total cholesterol in the model was significantly related to CAD. Sex hormone-binding globulin and dehydroepiandrosterone sulfate, added individually to the model, showed no significant relationship to CAD. These results raise the possibility that in women an elevated FT level may be a risk factor for coronary atherosclerosis.
Publication
Journal: Obesity research
July/22/1998
Abstract
OBJECTIVE
Leptin, an adipocyte-secreted hormone, has been shown to signal the status of energy stores to the brain, regulate energy homeostasis, and mediate the neuroendocrine response to food deprivation. Obesity is associated with increased leptin levels, and several hormones, including insulin and glucocorticoids, have been associated with leptin levels and expression in rodents. Although obesity has been strongly associated with increased leptin in humans, a significant percentage of leptin's variability remains unexplained. The role of endogenous hormones, demographic factors, or certain life-style factors in explaining the residual variability of leptin levels has not yet been clarified. We performed this cross-sectional study to document the relative importance of obesity, lifestyle factor, and endogenous hormones in determining serum leptin levels.
METHODS
We measured serum concentrations of insulin, cortisol, testosterone, growth hormone, and dehydroepiandrosterone sulfate; ascertained anthropometric, demographic, and lifestyle characteristics; and studied these variables in relationship to serum leptin concentrations in a sample of young healthy men.
RESULTS
Obesity and alcohol intake were independently and positively associated with circulating leptin concentrations. Additionally, cigarette smoking was negatively and independently associated with leptin concentrations. Finally, serum insulin concentration was an independent hormonal determinant of circulating leptin concentrations, whereas serum testosterone was negatively associated with leptin only by bivariate analysis.
CONCLUSIONS
We conclude that, in addition to obesity, cigarette smoking, alcohol intake, and serum insulin levels are associated with leptin levels in a population of healthy young men.
Publication
Journal: Endocrinology
February/2/2006
Abstract
Steroids in the brain arise both from local synthesis and from peripheral sources and have a variety of effects on neuronal function. However, there is little direct chemical evidence for the range of steroids present in brain or of the pathways for their synthesis and inactivation. This information is a prerequisite for understanding the regulation and function of brain steroids. After extraction from adult male rat brain, we have fractionated free steroids and their sulfate esters and then converted them to heptafluorobutyrate or methyloxime-trimethylsilyl ether derivatives for unequivocal identification and assay by gas chromatography analysis and selected ion monitoring mass spectrometry. In the free steroid fraction, corticosterone, 3alpha,5alpha-tetrahydrodeoxycorticosterone, testosterone, and dehydroepiandrosterone were found in the absence of detectable precursors usually found in endocrine glands, indicating peripheral sources and/or alternative synthetic pathways in brain. Conversely, the potent neuroactive steroid 3alpha,5alpha-tetrahydroprogesterone (allopregnanolone) was found in the presence of its precursors pregnenolone, progesterone, and 5alpha-dihydroprogesterone. Furthermore, the presence of 3beta-, 11beta-, 17alpha-, and 20alpha-hydroxylated metabolites of 3alpha,5alpha-tetrahydroprogesterone implicated possible inactivation pathways for this steroid. The 20alpha-reduced metabolites could also be found for pregnenolone, progesterone, and 5alpha-dihydroprogesterone, introducing a possible regulatory diversion from the production of 3alpha,5alpha-tetrahydroprogesterone. In the steroid sulfate fraction, dehydroepiandrostrone sulfate was identified but not pregnenolone sulfate. Although pharmacologically active, identification of the latter appears to be an earlier methodological artifact, and the compound is thus of doubtful physiological significance in the adult brain. Our results provide a basis for elucidating the origins and regulation of brain steroids.
Publication
Journal: Endocrinology
October/28/2003
Abstract
Pulsatile GnRH release is required for fertility and is regulated by steroid feedback. Whether or not steroids or their metabolites act directly on GnRH neurons is not well established. In some neurons, steroid metabolites known as neurosteroids modulate the function of the GABAA receptor. Specifically, the progesterone derivative allopregnanolone is an allosteric agonist at this receptor, whereas the androgen dehydroepiandrosterone sulfate (DHEAS) is an allosteric antagonist. We hypothesized these metabolites act similarly on GnRH neurons to modify the response to GABA. Whole-cell voltage-clamp recordings of GABAergic miniature postsynaptic currents (mPSCs) were made from green fluorescent protein-identified GnRH neurons in brain slices from diestrous mice. Glutamatergic currents were blocked with antagonists and action potentials blocked with tetrodotoxin, minimizing presynaptic effects of treatments. Allopregnanolone (5 microm) increased mPSC rate of rise, amplitude and decay time by 15.9 +/- 6.1%, 16.5 +/- 6.3%, and 58.3 +/- 18.6%, respectively (n = 7 cells). DHEAS (5 microm) reduced mPSC rate of rise (32.1 +/- 5.7%) and amplitude (27.6 +/- 4.3%) but did not alter decay time (n = 8). Effects of both neurosteroids were dose dependent between 0.1 and 10 microm. In addition to independent actions, DHEAS also reversed effects of allopregnanolone on rate of rise and amplitude so that these parameters were returned to pretreatment baseline values (n = 6). These data indicate allopregnanolone increases and DHEAS decreases responsiveness of GnRH neurons to activation of GABAA receptors by differentially modulating current flow through GABAA receptor chloride channels. This provides one mechanism for direct steroid feedback to GnRH neurons.
Publication
Journal: International Journal of Developmental Neuroscience
July/5/1999
Abstract
Astrocytes are a target for steroid hormones and for steroids produced by the nervous system (neurosteroids). The effect of gonadal hormones and several neurosteroids in the formation of gliotic tissue has been assessed in adult male rats after a penetrating wound of the cerebral cortex and the hippocampal formation. The hormones testosterone, 17beta-estradiol and progesterone and the neurosteroids dehydroepiandrosterone, pregnenolone and pregnenolone sulfate resulted in a significant decrease in the accumulation of astrocytes in the proximity of the wound and in a decreased bromodeoxyuridine incorporation in reactive astrocytes. Of all steroids tested, dehydroepiandrosterone was the most potent inhibitor of gliotic tissue formation. These findings suggest that neurosteroids and sex steroids may affect brain repair by down-regulating gliotic tissue.
Publication
Journal: CNS Neuroscience and Therapeutics
September/21/2010
Abstract
BACKGROUND
Dopamine cell loss is well documented in Parkinson's disease and dopamine hypofunction is proposed in certain depressive states. At the opposite, dopamine hyperactivity is an enduring theory in schizophrenia with extensive supporting evidence.
OBJECTIVE
This article reviews the sex differences in these diseases that are the object of many studies and meta-analyses and could be explained by genetic differences but also an effect of steroids in the brain. This article then focuses on the extensive literature reporting on the effect of estrogens in these diseases and effects of the other ovarian hormone progesterone as well as androgens that are less documented. Moreover, dehydroepiandrosterone, the precursor of estrogens and androgens, shows effects on brain dopamine neurotransmission that are reviewed. To investigate the mechanisms implicated in the human findings, animal studies are reviewed showing effects of estrogens, progesterone, and androgens on various markers of dopamine neurotransmission under intact as well as lesioned conditions.
CONCLUSIONS
For possible future avenues for hormonal treatments in these central nervous system diseases, we discuss the effects of selective estrogen receptor modulators (SERMs), the various estrogen receptors and their specific drugs as well as progesterone drugs.
CONCLUSIONS
Clinical and experimental evidence supports a role of steroid-dopamine interactions in the pathophysiology of schizophrenia, depression and Parkinson's disease. Specific steroidal receptor agonists and SERMs are available for endocrine and cancer treatments and could find other applications as adjunct treatments in central nervous system diseases.
Publication
Journal: The Journal of trauma
April/9/2008
Abstract
BACKGROUND
Sex hormones exhibit predictable changes in their physiologic patterns during critical illness. Endogenous estrogens are elevated in both genders as a result of the peripheral conversion of androgens to estrogens by the aromatase enzyme. Elevated endogenous estrogens have been associated with death in medical and mixed surgical intensive care unit (ICU) patients. Our objective was to determine the relationship between endogenous estrogens and outcomes in critically injured patients.
METHODS
A prospective cohort of injured patients remaining in the ICU for at least 48 hours at two trauma centers was enrolled. Sex hormones (estradiol, progesterone, testosterone, prolactin, and dehydroepiandrosterone-sulfate) were assayed and mortality was assessed. A logistic regression model was used to determine the association between estradiol and death. The area under the receiver operating characteristic (AUROC) curve was used to estimate the accuracy of estradiol in predicting death.
RESULTS
Nine hundred ninety-one patients were enrolled with a 13.4% mortality rate. Despite no detectable difference in mortality among genders, estradiol was significantly elevated in nonsurvivors (16 pg/mL vs. 35 pg/mL, p < 0.001). Estradiol was a marker for injury severity with the most severely injured patients exhibiting the highest levels. The ability of estradiol to predict death (AUROC = 0.65) was comparable with Trauma and Injury Severity Score (AUROC = 0.65) and superior to Injury Severity Score (AUROC = 0.54) in this cohort.
CONCLUSIONS
Serum estradiol is a marker of injury severity and a predictor of death in the critically injured patient, regardless of gender. Whether or not estradiol plays a causal role in outcomes is unclear, but estrogen modulation represents a potential therapy for improving outcomes in critically ill trauma patients.
Publication
Journal: Archives of Biochemistry and Biophysics
August/17/1994
Abstract
A T7 expression system is described for the high-level production in Escherichia coli of the membrane-bound form of human and rat cytochrome b5. The cDNAs of b5 have been engineered to contain a coding sequence for a four-member histidine domain at the amino-terminus of the recombinant protein permitting the use of a nickel-chelate affinity column for rapid purification of the detergent-solubilized hemoprotein. Results are presented demonstrating the ability of the purified recombinant b5 proteins to stimulate the rate of oxidation of 17 alpha-hydroxypregnenolone to dehydroepiandrosterone, catalyzed by bovine P450 17A, and to stimulate the 6 beta-hydroxylation of testosterone, catalyzed by human P450 3A4. These P450-catalyzed reactions have been used to compare the properties of different forms of b5. Purified b5 can serve as a "coupling protein" as illustrated by its inhibition of NADPH oxidation, catalyzed by a fusion protein containing the heme domain of P450 3A4 linked to rat NADPH-P450 reductase, and the associated inhibition of hydrogen peroxide formation. Kinetic studies show the formation of a complex of the flavoprotein, NADPH-P450 reductase, with b5 for the rapid transfer of electrons from NADPH.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
May/26/1983
Abstract
The principal glandular source of increased serum androgens in polycystic ovarian disease (PCO) is controversial), since complete separation of ovarian from adrenal function has not been achieved. The purpose of this study was to determine whether a long-acting GnRH agonist could be used to selectively inhibit ovarian steroid secretion in PCO and ovulatory women. Each of five typical PCO patients and six ovulatory subjects on day 2 of their menstrual cycles received D-Trp6-Pro9-NEt-LHRH (GnRH-a; 100 micrograms) for 28 consecutive days. Their results were compared to basal serum hormone values in eight oophorectomized women. In response to GnRH-a, PCO and normal subjects exhibited sharp and sustained rises of LH and gradual decreases in FSH. These levels were clearly less than basal levels seen in oophorectomized women. Episodic LH release was significantly attenuated in both groups at the end of GnRH-a treatment. After the administration of agonist, serum estradiol (E2), estrone (E1), androstenedione (A), and testosterone (T) were suppressed to castrate levels in both groups. The decrements of E2 and E1 in PCO were gradual and continuous compared to initial dramatic rises, which reached peaks at 14 days, and subsequent abrupt falls in the ovulatory controls. Serum A and T declined steadily in both groups. Basal serum dehydroepiandrosterone and dehydroepiandrosterone sulfate, but not cortisol, levels were elevated in PCO subjects. The 24-h secretion patterns and responses to ACTH of these hormones in PCO and ovulatory subjects were unaltered by GnRH-a administration. These data demonstrate that 1) in PCO subjects, GnRH-a induced complete suppression of ovarian steroid secretion, as circulating levels at the end of treatment were comparable to those seen in our oophorectomy subjects; 2) elevated A and T levels in PCO patients were derived primarily from the ovary; and 3) adrenal steroid secretion was unaltered by GnRH-a in both PCO and normal women.
Publication
Journal: Pediatric Research
October/10/2001
Abstract
Premature infants have higher cortisol precursor concentrations than term infants; however, many sick preterm infants have surprisingly low cortisol concentrations. Those who develop chronic lung disease (CLD) have lower cortisol values than those who recover. We hypothesized that some infants have a decreased ability to synthesize cortisol, leading to physiologic disruptions including amplified inflammatory responses, thereby resulting in CLD. We measured cortisol, 11-deoxycortisol, 17-hydroxyprogesterone, 17-hydroxypregnenolone, dehydroepiandrosterone sulfate, and ACTH in 40 extremely low birth weight infants enrolled in a study of low-dose hydrocortisone therapy to prevent CLD. Thirty-four infants survived and 15 developed CLD. Hydrocortisone therapy did not suppress ACTH or any measured steroid value. Before study (<48 h of life), 17-OH progesterone was higher in CLD infants, as was the ratio of 17-OH progesterone to 11-deoxycortisol. On d 15-19 >> or =72 h after end of therapy), basal and stimulated cortisol concentrations were lower in CLD infants. In contrast, the basal ratio of 11-deoxycortisol to cortisol was higher in CLD infants, as were stimulated values of 17-OH progesterone and stimulated ratios of 17-OH progesterone to 11-deoxycortisol and 11-deoxycortisol to cortisol. Thus, infants who developed CLD had lower basal and stimulated cortisol values, but elevated cortisol precursors and precursor to product ratios, compared with infants who recovered. These data support the hypothesis that these immature infants have a decreased capacity to synthesize cortisol, which may lead to a relative adrenal insufficiency in the face of significant illness.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
July/8/2004
Abstract
The neuroactive steroids dehydroepiandrosterone (DHEA), its sulfate ester DHEA sulfate (DHEAS), and allopregnanolone (Allo), produced by the CNS and the adrenals, appear to exert a protective effect in hippocampal and cortical neuron ischemia- and excitotoxicity-induced injury. We hypothesized that they may also play a protective role on the adrenal medulla, an important part of the sympathetic nervous system, and the tissue adjacent to their primary site of production. DHEA, DHEAS, and Allo protected rat chromaffin cells and the rat pheochromocytoma PC12 cell line, an established model for the study of adrenomedullary cell apoptosis and survival, against serum deprivation-induced apoptosis. Their effects were time- and dose-dependent, with EC50 1.8, 1.1, and 1.5 nM, respectively. The antiapoptotic effect of DHEA DHEAS and Allo was compared to that of a long list of structurally related compounds and was found to be structure-specific, confined mainly to conformation 3beta-OH-Delta5 for androstenes and 3alpha-OH for pregnanes. Indeed, 3-keto, Delta4, or C7 hydroxylated androstenes and 3beta pregnanes were ineffective. The prosurvival effect of DHEA(S) and Allo was N-methyl-D-aspartate-, GABAA-, sigma1-, or estrogen receptor-independent. It involved the antiapoptotic Bcl-2 proteins, their role being sine qua non for their action because Bcl-2 antisense oligonucleotides reversed their effects. Finally, DHEA(S) and Allo activated cAMP response element-binding protein and NF-kappaB, upstream effectors of antiapoptotic Bcl-2 protein expression. They also activated the antiapoptotic kinase PKCalpha/beta, a posttranslational activator of Bcl-2 protein. Our findings suggest that decline of DHEA(S) and Allo during aging or stress may leave the adrenal medulla unprotected against proapoptotic challenges.
Publication
Journal: Genomics
December/30/1998
Abstract
We have cloned and characterized cDNAs that encode two human hydroxysteroid sulfotransferase (SULT) enzymes, SULT2B1a and SULT2B1b, as well as the single gene that encodes both of these enzymes. The two cDNAs differed at their 5'-termini and had 1050- and 1095-bp open reading frames that encoded 350 and 365 amino acids, respectively. The amino acid sequences encoded by these cDNAs included "signature sequences" that are conserved in all known cytosolic SULTs. Both cDNAs appeared, on the basis of amino acid sequence analysis, to be members of the hydroxysteroid SULT "family, " SULT2, but they were only 48% identical in amino acid sequence with the single known member of that family in humans, SULT2A1 (also referred to as DHEA ST). Northern blot analysis demonstrated the presence of SULT2B1 mRNA species approximately 1.4 kb in length in human placenta, prostate, and trachea and-faintly-in small intestine and lung. Expression of the two human SULT2B1 cDNAs in COS-1 cells showed that both of the encoded proteins catalyzed sulfation of the prototypic hydroxysteroid SULT substrate, dehydroepiandrosterone, but both failed to catalyze the sulfate conjugation of 4-nitrophenol or 17beta-estradiol, prototypic substrates for the phenol and estrogen SULT subfamilies. Both of these cDNAs were encoded by a single gene, SULT2B1. The locations of most exon-intron splice junctions in SULT2B1 were identical to those of the only other known human hydroxysteroid SULT gene SULT2A1 (previously STD). The divergence in 5'-terminal sequences of the two SULT2B1 cDNAs resulted from alternative transcription initiation prior to different 5' exons, combined with alternative splicing. SULT2B1 mapped to human chromosome band 19q13.3, approximately 500 kb telomeric to the location of SULT2A1.
Publication
Journal: Stroke
August/28/2000
Abstract
OBJECTIVE
Dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS) may function as neurotrophic or neuroprotective factors to protect central nervous system (CNS) neurons against a variety of insults, including excitotoxicity. The present study evaluated the pharmacological effects of DHEAS in a reversible spinal cord ischemia model.
METHODS
DHEAS was administered (50 mg/kg IV) 5 or 30 minutes after the start of occlusion to groups of rabbits exposed to ischemia induced by temporary (15 to 60 minutes) occlusion of the infrarenal aorta. The group P(50) represents the duration of ischemia (in minutes) associated with 50% probability of resultant permanent paraplegia.
RESULTS
The P(50) of the vehicle-treated control group, when behavioral analysis was assessed 18 hours after aortal occlusion, was 28.8+/-2.0 minutes. Neuroprotection was demonstrated if a drug significantly prolonged the P(50) compared with the vehicle-treated control group. Treatment with DHEAS at 5 minutes significantly (P<0.05) prolonged the P(50) of the group to 36.8+/-3.9 minutes. In addition, the DHEAS effect appeared durable, because a significant difference between the control and DHEAS-treated groups was still measurable at the 4-day time point. At 4 days, the P(50) of the control group was 26.1+/-2.2 minutes, whereas the P(50) for the DHEAS-treated group was 38.6+/-5. 9 minutes. DHEAS was not neuroprotective if administered 30 minutes after occlusion. In addition, the GABA(A) antagonist bicuculline abolished the neuroprotective effect of DHEAS.
CONCLUSIONS
The present study suggests that neurosteroids may have substantial therapeutic benefit for the treatment of ischemic stroke.
Publication
Journal: Psychoneuroendocrinology
March/12/2003
Abstract
BACKGROUND
An association between abnormal changes in reproductive endocrine function during the perimenopause and the onset of depression in some women has been suggested but remains controversial.
METHODS
We examined basal plasma hormone levels in two samples of women with well characterized, first onset depression (major or minor) during the perimenopause and matched comparison groups of asymptomatic women. Results were compared by analysis of variance.
RESULTS
No significant diagnosis-related differences were observed in plasma hormone measures of the following: follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), estrone (E1), total (T) or free testosterone (FT), or the E2/LH ratio. We did identify significantly lower morning plasma dehydroepiandrosterone (DHEA) and its sulphated metabolite DHEA-S (but not cortisol) levels in the depressed women compared to the non-depressed comparison group. Women with hot flushes (regardless of the presence of depression) were significantly older than women without flushes, had significantly higher plasma levels of FT, LH and FSH, and had significantly lower E2/LH ratios.
CONCLUSIONS
Women with first onset depression during the perimenopause are not distinguished from controls on the basis of basal hormone measures of ovarian estrogens, testosterone, or gonadotropins. However, perimenopause-related changes in E2 may interact with low levels of DHEA in some women to increase their vulnerability to develop depression. In contrast to perimenopause-related vasomotor symptoms, depression during the perimenopause is not associated with a simple hormone deficiency state. The relatively low levels of E2 and E1 in the depressed women may have met statistical significance in a much larger and homogenous sample.
Publication
Journal: Journal of Biological Chemistry
August/15/2001
Abstract
The major adrenal steroid dehydroepiandrosterone (DHEA) enhances memory and immune function but has no known dedicated receptor; local metabolism may govern its activity. We described a cytochrome P450 expressed in brain and other tissues, CYP7B, that catalyzes the 7alpha-hydroxylation of oxysterols and 3beta-hydroxysteroids including DHEA. We report here that CYP7B mRNA and 7alpha-hydroxylation activity are widespread in rat tissues. However, steroids related to DHEA are reported to be modified at positions other than 7alpha, exemplified by prominent 6alpha-hydroxylation of 5alpha-androstane-3beta,17beta-diol (A/anediol) in some rodent tissues including brain. To determine whether CYP7B is responsible for these and other activities we disrupted the mouse Cyp7b gene by targeted insertion of an IRES-lacZ reporter cassette, placing reporter enzyme activity (beta-galactosidase) under Cyp7b promoter control. In heterozygous mouse brain, chromogenic detection of reporter activity was strikingly restricted to the dentate gyrus. Staining did not exactly reproduce the in situ hybridization expression pattern; post-transcriptional control is inferred. Lower level staining was detected in cerebellum, liver, and kidney, and which largely paralleled mRNA distribution. Liver and kidney expression was sexually dimorphic. Mice homozygous for the insertion are viable and superficially normal, but ex vivo metabolism of DHEA to 7alpha-hydroxy-DHEA was abolished in brain, spleen, thymus, heart, lung, prostate, uterus, and mammary gland; lower abundance metabolites were also eliminated. 7alpha-Hydroxylation of 25-hydroxycholesterol and related substrates was also abolished, as was presumed 6alpha-hydroxylation of A/anediol. These different enzyme activities therefore derive from the Cyp7b gene. CYP7B is thus a major extrahepatic steroid and oxysterol hydroxylase and provides the predominant route for local metabolism of DHEA and related molecules in brain and other tissues.
Publication
Journal: Fertility and Sterility
April/3/2003
Abstract
OBJECTIVE
In women suffering from polycystic ovary syndrome (PCOS), correction of hyperinsulinemia results enhances spontaneous ovulation or alternatively, the responsiveness to ovulation induction agents such as clomiphene citrate (CC). We investigated the effect of rosiglitazone maleate on ovulation induction in overweight and obese, CC-resistant women with PCOS.
METHODS
Double-blind, randomized, placebo-controlled trial.
METHODS
Academic reproductive endocrinology clinic.
METHODS
Overweight and obese women with clinical and laboratory manifestations of PCOS who desired pregnancy and were resistant to CC.
METHODS
Twenty-five women were randomized into two treatment groups. Subjects in Group I (n = 12) were randomized to receive rosiglitazone 4 mg b.i.d. with a placebo on cycle days 5-9. Group II (n = 13) was randomized to receive rosiglitazone 4 mg b.i.d. with CC on cycle days 5-9. The duration of the study was 2 months.
METHODS
The primary outcome was ovulation as defined by luteal serum progesterone greater than 5 ng/dL assessed on days 21, 24, and 28 of the cycle. Secondary outcomes were pregnancy and changes in insulin sensitivity, serum lipoproteins, and androgens.
RESULTS
Overall, 14 of 25 (56%) women, who were previously resistant to CC, successfully ovulated. In subjects taking rosiglitazone alone (Group I), 4 of 12 (33%) subjects ovulated compared with 10 of 13 (77%) women randomized to rosiglitazone with CC (Group II) (P=.04, Fisher's exact). One subject in Group I became pregnant, resulting in one uncomplicated live birth; two subjects in Group II conceived, with one successful live birth and one first trimester, spontaneous abortion. For all subjects, fasting insulin declined from 29.4 +/- 13.8 microU/mL to 17.3 +/- 7.8 microU/mL after rosiglitazone (P=.003, paired t-test). Although mean levels of total testosterone (T) and dehydroepiandrosterone sulfate (DHEAS) did not decline significantly, sex hormone-binding globulin (SHBG) did increase from 0.7 +/- 0.3 microg/dL to 1.0 +/- 0.3 microg/dL after rosiglitazone therapy (P=.001, paired t test). There was also a decrease in luteinizing hormone (LH) from 9.4 +/- 6.3 mU/mL to 7.2 +/- 3.7 mU/mL (P=.01). Lipoproteins including total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides did not change.
CONCLUSIONS
Short-term rosiglitazone therapy enhances both spontaneous and clomiphene-induced ovulation in overweight and obese women with PCOS. Rosiglitazone therapy improves insulin sensitivity and decreases hyperandrogenemia primarily through increases in SHBG.
Publication
Journal: Pediatric Research
November/25/2002
Abstract
Among pathologies prevalent in western societies, anorexia nervosa has increased over the last decade. Its effects on bone mass need to be defined, and prognostic factors, either clinical or biochemical, could aid clinicians in individual patient management. To determine which clinical and/or biochemical parameters could be related to bone mass status in adolescent female anorexia nervosa patients, 73 female patients were classified according to different stages of their illness and studied in terms of clinical and biochemical parameters and bone densitometric mineral content at lumbar spine. Patients (age 17.2 +/- 1.7 y, mean +/- SD) with Tanner pubertal stage 5, regular menstruation for more than 3 mo before the onset of secondary amenorrhea, and diagnosed with anorexia nervosa were consecutively studied and classified in three clinical situations: I) active phase (34 patients): undernourished and amenorrheic; II) weight recovered but still amenorrheic (20 patients); III) fully recovered (19 patients). Clinical data were recorded at the time of bone density measurement, concomitant with blood sample extraction for study of IGF-I, IGF-binding protein 3 (IGFBP-3), IGFBP-1, estradiol, sex hormone-binding globulin, dehydroepiandrosterone sulfate, prealbumin, amino-terminal propeptide of procollagen III, osteocalcin, bone alkaline phosphatase, carboxy-terminal propeptide of procollagen I, amino-terminal propeptide of procollagen I, carboxy-terminal telopeptide of collagen I, 25-OH-vitamin D, 1,25(OH)(2)-vitamin D, and parathormone. In addition, a 24-h urine collection was made for cortisol, GH, deoxypyridinoline, amino-terminal telopeptide of collagen I, and calcium and creatinine content analysis. IGF-I, estradiol, and biochemical bone formation markers were higher and IGFBP-1, sex hormone-binding globulin, and biochemical bone resorption markers were lower in the weight-recovered stages (stages II and III) compared with the active phase (stage I). Bone formation markers correlated positively with body mass index SD score and IGF-I, whereas bone resorption markers correlated negatively with body mass index SD score and estradiol. Although no statistically significant differences regarding lumbar spine bone mineral density SD score values were recorded among the three stages of the illness, the proportion of osteopenic patients was clearly lower among stage III patients. The actual bone mineral density was inversely related to the duration of amenorrhea and directly related to duration of postmenarcheal menses before amenorrhea. In addition, a subset of osteopenic patients (five of 19) in the fully clinically recovered group with accelerated bone turnover was identified. Normal circulating estrogen level exposure time predicts actual bone mineral density at lumbar spine in young adolescent anorexia nervosa patients. In addition to psychiatric and nutritional interventions, estrogen-deprivation periods must be shortened to less than 20 mo. Patients remaining osteopenic at full clinical recovery require additional follow-up studies.
Publication
Journal: Journal of Neuroscience
September/4/2013
Abstract
Humans and the great apes are the only species demonstrated to exhibit adrenarche, a key endocrine event associated with prepubertal increases in the adrenal production of androgens, most significantly dehydroepiandrosterone (DHEA) and to a certain degree testosterone. Adrenarche also coincides with the emergence of the prosocial and neurobehavioral skills of middle childhood and may therefore represent a human-specific stage of development. Both DHEA and testosterone have been reported in animal and in vitro studies to enhance neuronal survival and programmed cell death depending on the timing, dose, and hormonal context involved, and to potentially compete for the same signaling pathways. Yet no extant brain-hormone studies have examined the interaction between DHEA- and testosterone-related cortical maturation in humans. Here, we used linear mixed models to examine changes in cortical thickness associated with salivary DHEA and testosterone levels in a longitudinal sample of developmentally healthy children and adolescents 4-22 years old. DHEA levels were associated with increases in cortical thickness of the left dorsolateral prefrontal cortex, right temporoparietal junction, right premotor and right entorhinal cortex between the ages of 4-13 years, a period marked by the androgenic changes of adrenarche. There was also an interaction between DHEA and testosterone on cortical thickness of the right cingulate cortex and occipital pole that was most significant in prepubertal subjects. DHEA and testosterone appear to interact and modulate the complex process of cortical maturation during middle childhood, consistent with evidence at the molecular level of fast/nongenomic and slow/genomic or conversion-based mechanisms underlying androgen-related brain development.
Publication
Journal: International Immunology
August/25/1997
Abstract
Constitutive expression of p35 and p40 IL-12 mRNA was detected in splenic macrophages isolated from aged mice. Macrophages were also implicated as the cell type responsible for the dysregulated IL-6 and tumor necrosis factor (TNF)-alpha commonly observed to be constitutively produced by lymphoid cells from aged donors. A role for IL-12 in the aging process was suggested when it was found that recombinant IL-12 (rIL-12) directly stimulated splenic CD5+ B cells to secrete IL-10, and both CD5+ and CD5- B cells could be directly induced to produce IL-6 in response to rIL-12. Furthermore, splenocytes from aged animals cultured in the presence of anti-IL-12 antibodies demonstrated a significant reduction in spontaneous IL-6, IL-10 and IFN-gamma production. Based on these observations it was concluded that IL-12 might be responsible for the dysregulated production of IL-10 and IFN-gamma known to occur in aged animals. Treatment of aged animals with low doses of dehydroepiandrosterone sulfate, previously established to be immunocorrective in immunosenescent animals, reduced the age-associated alterations in IL-12 mRNA and protein expression. The mechanisms responsible for the abnormal constitutive expression of inflammatory cytokines by the macrophages of aged animals may play an important afferent role in establishing the immunosenescent phenotype.
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