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Publication
Journal: GLIA
July/6/1997
Abstract
Effects of steroid hormones on the regulation of function and morphology of microglial cells were investigated using the cultured cells isolated from forebrain of newborn rats. Cortisol, corticosterone, and aldosterone at 100 nM caused a strong shrinkage of microglial cells cultured in a serum-supplemented medium. However, cholesterol, pregnenolone, testosterone, estradiol, and dehydroepiandrosterone did not exhibit any significant effects. The corticosteroids also inhibited the GM-CSF-mediated ramification of microglia in a serum-free medium. An anti-glucocorticoid agent RU38486 abolished the effects of corticosteroids on the microglial morphology, suggesting the presence of functional glucocorticoid receptor (GR) in microglial cells. The presence of GR was confirmed by immunoblotting with an antibody to the receptor. Cytokines GM-CSF and interleukin-3 altered the level of GR expression. Binding experiments with [3H]-corticosterone demonstrated the presence of not only GR but also mineralocorticoid receptor (MR): the dissociation constants (Kd) and the number of binding sites (Bmax) were 0.8 nM and 15 fmol/mg protein for MR and 5.0 nM and 73 fmol/mg protein for GR, respectively. The pure glucocorticoid RU28362 and dexamethasone at 20 nM (but not aldosterone and corticosterone at the same concentration) inhibited proliferation of microglial cells, as revealed by PCNA immunocytochemistry. RU28362 inhibited the activities of inducible nitric oxide synthase and acid phosphatase at concentrations higher than 1 nM. Aldosterone and corticosterone exhibited the similar inhibitory effect at 100 nM, and this inhibition was completely overcome by RU38486. On the other hand, corticosterone and aldosterone at concentrations lower than 1 nM enhanced the activities of both enzymes. The antimineralocorticoid agent spironolactone eliminated the stimulatory effects of corticosterone on the enzyme activities. In accordance with these biochemical results, electron microscopic observations revealed that glucocorticoids enhanced the formation of lysosomal vacuolation in microglial cells and aldosterone increased the number and size of lysosomes. In conclusion, it is suggested that GR and MR mediated the opposite effects of corticosterone on the functions of microglial cells; the hormone acted as an inhibitor through GR and as an stimulator through MR.
Publication
Journal: New England Journal of Medicine
June/4/2009
Abstract
Dehydroepiandrosterone (DHEA) sulfotransferase, known as SULT2A1, converts the androgen precursor DHEA to its inactive sulfate ester, DHEAS [corrected], thereby preventing the conversion of DHEA to an active androgen. SULT2A1 requires 3'-phosphoadenosine-5'-phosphosulfate (PAPS) for catalytic activity. We have identified compound heterozygous mutations in the gene encoding human PAPS synthase 2 (PAPSS2) in a girl with premature pubarche, hyperandrogenic anovulation, very low DHEAS levels, and increased androgen levels. In vitro coincubation of human SULT2A1 and wild-type or mutant PAPSS2 proteins confirmed the inactivating nature of the mutations. These observations indicate that PAPSS2 deficiency is a monogenic adrenocortical cause of androgen excess.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
September/10/2003
Abstract
Circulating hormones and local biotransformation of steroid precursors are both sources of estrogen in human mammary tissue. Estrone-3-sulfate (E(1)S) is an important estrogenic form in premenopausal women, and dehydroepiandrosterone sulfate (DHEAS) constitutes a major adrenal precursor. Membrane transport systems that govern delivery of these anionic steroid conjugates to the mammary gland were investigated. RNA was screened by RT-PCR and Northern blotting for expression of organic anion transporting polypeptide (OATP) (solute carrier family 21A) and organic anion transporter (OAT) (solute carrier family 22A) gene families. OATP-B (SLC21A9) was the major carrier expressed; OATP-D (SLC21A11) and OATP-E (SLC21A12) were less abundant. In normal sections, OATP-B immunolocalized to the myoepithelium that surrounds the ductal epithelial cells. In invasive carcinoma, ductal epithelial cells were positive. OATP-B was characterized in stable transfected Chinese hamster ovary cells. E(1)S affinity constant (K(m)) [K(m) = 5 micro mol/liter, maximum velocity (V(max)) V(max) = 777 pmol/mg.min] and DHEAS (K(m) = 9 micro mol/liter, V(max) = 85 pmol/mg.min) were substrates. The prostaglandins (PG) A(1) and PGA(2) stimulated uptake of E(1)S and DHEAS by increasing V(max) 2-fold but not changing K(m). The effect of PGA was selectively blocked by the lipophilic thiol reagent N-ethylmaleimide but not by the hydrophilic acetamido-4'(iodoacetyl)aminostilbene-2,2'-disulfonic acid, suggesting an interaction between the electrophilic cyclopentenone ring and specific cysteine residues of OATP-B.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
June/8/2005
Abstract
Polycystic ovary syndrome (PCOS), a common endocrinopathy of women of reproductive age, is associated with the early appearance of multiple risk factors for cardiovascular disease, such as abdominal obesity, dyslipidemia, and diabetes mellitus. However, premature atherosclerosis of the carotid artery has not yet been demonstrated in young women with PCOS. Measurement of carotid intima-media thickness (IMT) is considered an easy and reliable index of subclinical atherosclerosis, which is predictive of subsequent myocardial infarction and stroke. To evaluate the cardiovascular risk of PCOS and the participation of the hyperandrogenemic and metabolic pattern, we measured carotid IMT by B-mode ultrasound as well as hormonal and several cardiovascular disease-associated parameters in 75 young women with PCOS and 55 healthy, age- and body mass index-matched women. The PCOS women had significantly increased carotid IMT (0.58 vs. 0.47 mm, P < 0.001) and abdominal adiposity; higher levels of androgens, insulin, homeostasis model assessment score of insulin sensitivity, and total and low-density lipoprotein-cholesterol; and significantly lower levels of SHBG and high-density lipoprotein-cholesterol. In the studied population (n = 130), PCOS status, age, body mass index, and parental history of coronary heart disease were strong positive predictors of carotid IMT, whereas dehydroepiandrosterone sulfate was a strong negative predictor. In PCOS patients lower delta4-androstenedione and high-density lipoprotein-cholesterol levels were additionally strong positive predictors of carotid IMT, whereas in control women only total cholesterol was the additional positive predictor of carotid IMT. In conclusion, young women with PCOS have an early increase of cardiovascular risk factors and greater carotid IMT, both of which may be responsible for subclinical atherosclerosis. The hyperandrogenemic phenotype of the syndrome may attenuate the consequences of the dysmetabolic phenotype on the vascular wall.
Publication
Journal: Clinical Endocrinology
April/23/2012
Abstract
BACKGROUND
Estimates of intraindividual variation in hormone levels provide the basis for interpreting hormone measurements clinically and for developing eligibility criteria for trials of hormone replacement therapy. However, reliable systematic estimates of such variation are lacking.
OBJECTIVE
To estimate intraindividual variation of serum total, free and bioavailable testosterone (T), dihydrotestosterone (DHT), SHBG, LH, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate (DHEAS), oestrone, oestradiol and cortisol, and the contributions of biological and assay variation to the total.
METHODS
Paired blood samples were obtained 1-3 days apart at entry and again 3 months and 6 months later (maximum six samples per subject). Each sample consisted of a pool of equal aliquots of two blood draws 20 min apart.
METHODS
Men aged 30-79 years were randomly selected from the respondents to the Boston Area Community Health Survey, a study of the health of the general population of Boston, MA, USA. Analysis was based on 132 men, including 121 who completed all six visits, 8 who completed the first two visits and 3 who completed the first four visits.
METHODS
Day-to-day and 3-month (long-term) intraindividual standard deviations, after transforming measurements to logarithms to eliminate the contribution of hormone level to intraindividual variation.
RESULTS
Biological variation generally accounted for more of total intraindividual variation than did assay variation. Day-to-day biological variation accounted for more of the total than did long-term biological variation. Short-term variability was greater in hormones with pulsatile secretion (e.g. LH) than those that exhibit less ultradian variation. Depending on the hormone, the intraindividual standard deviations imply that a clinician can expect to see a difference exceeding 18-28% about half the time when two measurements are made on a subject. The difference will exceed 27-54% about a quarter of the time.
CONCLUSIONS
Given the level of intraindividual variability in hormone levels found in this study, one sample is generally not sufficient to characterize an individual's hormone levels but collecting more than three is probably not warranted. This is true for clinical measurements and for hormone measurements used to determine eligibility for a clinical trial of hormone replacement therapy.
Publication
Journal: International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity
February/16/1994
Abstract
An unfavourable body fat distribution may cause metabolic abnormalities including diabetes and dyslipidemia. These effects may be mediated by alterations in sex hormones. In women the available data suggest that upper body adiposity is related to increased androgenicity (especially as indicated by low concentrations of sex hormone binding globulin). Few data, however, are available on these relationships in men. We therefore examined the association of total testosterone, free testosterone, oestradiol, dehydroepiandrosterone sulphate (DHEA-SO4) and sex hormone binding globulin (SHBG) to waist-to-hip ratio (WHR) and conicity index in 178 men from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. The conicity index is equal to the abdominal circumference divided by 0.109 x the square root of (weight/height). The conicity index and WHR were significantly inversely related to DHEA-SO4 and free testosterone. SHBG was only weakly associated with body mass index (r = -0.18, P < 0.05). After adjustment for age and body mass index, DHEA-SO4 remained inversely correlated with WHR (r = -0.22, P < 0.01) and conicity index (r = -0.31, P < 0.001) and free testosterone remained inversely associated with conicity index (r = -0.21, P < 0.01). Thus, in men, the association between unfavourable body fat distribution and increased androgenicity is inverse in contrast to the situation in women.
Publication
Journal: Journal of Steroid Biochemistry and Molecular Biology
May/3/2012
Abstract
Surgical or pharmacologic methods to control gonadal androgen biosynthesis are effective approaches in the treatment of a variety of non-neoplastic and neoplastic diseases. For example, androgen ablation and its consequent reduction in circulating levels of testosterone is an effective therapy for advanced prostate cancers. Unfortunately, the therapeutic effectiveness of this approach is often temporary because of disease progression to the 'castration resistant' (CRPC) state, a situation for which there are limited treatment options. One mechanism thought to be responsible for the development of CRPC is extra-gonadal androgen synthesis and the resulting impact of these residual extra-gonadal androgens on prostate tumor cell proliferation. An important enzyme responsible for the synthesis of extra-gonadal androgens is CYP17A1 which possesses both 17,20-lyase and 17-hydroxylase catalytic activities with the 17,20-lyase activity being key in the androgen biosynthetic process. Orteronel (TAK-700), a novel, selective, and potent inhibitor of 17,20-lyase is under development as a drug to inhibit androgen synthesis. In this study, we quantified the inhibitory activity and specificity of orteronel for testicular and adrenal androgen production by evaluating its effects on CYP17A1 enzymatic activity, steroid production in monkey adrenal cells and human adrenal tumor cells, and serum levels of dehydroepiandrosterone (DHEA), cortisol, and testosterone after oral dosing in castrated and intact male cynomolgus monkeys. We report that orteronel potently suppresses androgen production in monkey adrenal cells but only weakly suppresses corticosterone and aldosterone production; the IC(50) value of orteronel for cortisol was ~3-fold higher than that for DHEA. After single oral dosing, serum levels of DHEA, cortisol, and testosterone were rapidly suppressed in intact cynomolgus monkeys. In castrated monkeys treated twice daily with orteronel, suppression of DHEA and testosterone persisted throughout the treatment period. In both in vivo models and in agreement with our in vitro data, suppression of serum cortisol levels following oral dosing was less than that seen for DHEA. In terms of human CYP17A1 and human adrenal tumor cells, orteronel inhibited 17,20-lyase activity 5.4 times more potently than 17-hydroxylase activity in cell-free enzyme assays and DHEA production 27 times more potently than cortisol production in human adrenal tumor cells, suggesting greater specificity of inhibition between 17,20-lyase and 17-hydroxylase activities in humans vs monkeys. In summary, orteronel potently inhibited the 17,20-lyase activity of monkey and human CYP17A1 and reduced serum androgen levels in vivo in monkeys. These findings suggest that orteronel may be an effective therapeutic option for diseases where androgen suppression is critical, such as androgen sensitive and CRPC.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
August/8/2001
Abstract
The decrease with age of the adrenal-secreted dehydroepiandrosterone sulfate (DHEAS) in serum has suggested that it may be causally related to longevity. For the PAQUID [People (Personnes) Aged (Agées) About What (Quid, in Latin)] cohort of elderly subjects, we have previously reported higher DHEAS in men than in women, a decrease with age and, among men, a negative correlation between the DHEAS level and mortality at 2 and 4 years. Here, with an 8-year followup in 290 subjects, we show a global decrease of 2.3% per year for men and 3.9% per year for women. However, in approximately 30% of cases, there was an increase of DHEAS. We observed no relationship between the evolution of DHEAS level and functional, psychological, and mental status, possibly because of selection by death. In women, no association was found between mortality and DHEAS level. In men, the relative risk (RR) of death was higher for the lowest levels of DHEAS (RR = 1.9, P = 0.007), with RR = 6.5, P = 0.003 for those under 70 years old, a result indicating heterogeneity of the population. There was an effect of subjective health on mortality that disappeared after adjustment of DHEAS levels, suggesting its relation with these DHEAS levels. Death RR was much higher in smokers with a low DHEAS level than in nonsmokers with high DHEAS (RR = 6.7, P = 0.001). We submit that the involvement of DHEAS is possibly different according to gender, that association between low DHEAS level and mortality only for men under 70 years old possibly reflects heterogeneity of the population, and that DHEAS level is a reliable predictor of death in male smokers.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
December/20/1995
Abstract
Immediate post-training, stereotactically guided, intraparenchymal administration of pregnenolone sulfate (PS) into the amygdala, septum, mammillary bodies, or caudate nucleus and of PS, dehydroepiandrosterone sulfate, and corticosterone into the hippocampus was performed in mice that had been weakly trained in a foot-shock active avoidance paradigm. Intrahippocampal injection of PS resulted in memory enhancement (ME) at a lower dose than was found with dehydroepiandrosterone sulfate and corticosterone. Intraamygdally administered PS was approximately 10(4) times more potent on a molar basis in producing ME than when PS was injected into the hippocampus and approximately 10(5) times more potent than when injected into the septum or mammillary bodies. ME did not occur on injection of PS into the caudate nucleus over the range of doses tested in the other brain structures. The finding that fewer than 150 molecules of PS significantly enhanced post-training memory processes when injected into the amygdala establishes PS as the most potent memory enhancer yet reported and the amygdala as the most sensitive brain region for ME by any substance yet tested.
Publication
Journal: Biochemical Journal
September/7/1989
Abstract
A form of sulphotransferase capable of sulphating dehydroepiandrosterone and other steroids was purified from cytosol prepared from human liver. Dehydroepiandrosterone sulphotransferase was purified 621-fold when compared with the activity in cytosol using DEAE-Sepharose CL-6B and adenosine 3',5'-bisphosphate-agarose affinity chromatography. During affinity chromatography, dehydroepiandrosterone sulphation activity could be resolved from p-nitrophenol sulphation activity catalysed by phenol sulphotransferase by using a gradient of adenosine 3'-phosphate 5'-phosphosulphate. The purified enzyme was most active towards dehydroepiandrosterone but was capable of conjugating a number of other steroids, including pregnenolone, androsterone and beta-oestradiol. No activity towards p-nitrophenol or dopamine, substrates for the phenol sulphotransferase, was observed with the pure enzyme. A single band with a subunit molecular mass of 35 kDa was observed by Coomassie Blue staining following SDS/polyacrylamide-gel electrophoresis of the purified enzyme. A molecular mass of 68-70 kDa was calculated for the active form of the enzyme by chromatography on Sephacryl S-200, suggesting that the active form of the enzyme is a dimer.
Publication
Journal: Journal of Neurophysiology
June/27/2006
Abstract
Membrane-associated receptors for rapid, steroidal neuromodulation remain elusive. Estradiol has been reported to facilitate activation of voltage- and Ca(2+)-dependent BK potassium channels encoded by Slo, if associated with beta1 subunits. We show here that 1) multiple members of the beta family confer sensitivity to multiple steroids on BK channels, 2) that beta subunits differentiate between steroids, and 3) that different betas have distinct relative preferences for particular steroids. Expressed in HEK 293 cells, inside-out patches with channels composed of Slo-alpha alone showed no steroid sensitivity. Cells expressing alphabeta4 exhibited potent, rapid, reversible, and dose-dependent potentiation by corticosterone (CORT; a glucocorticoid), and were potentiated to a lesser degree by other sex and stress steroids. In contrast, alphabeta2 channels were potentiated more strongly by dehydroepiandrosterone (DHEA; an enigmatic, stress-related adrenal androgen), and to a lesser extent by CORT, estradiol, testosterone, and DHEA-S. Cholesterol had no effect on any BK channel compositions tested. Conductance-voltage plots of channels composed of alpha plus beta2 or beta4 subunits were shifted in the negative direction by steroids, indicating greater activation at negative voltages. Thus our results argue that the variety of Slo-beta subunit coexpression patterns occurring in vivo expands the repertoire of Slo channel gating in yet another dimension not fully appreciated, rendering BK gating responsive to dynamic fluctuations in a multiple of steroid hormones.
Publication
Journal: Psychoneuroendocrinology
August/22/2001
Abstract
Dehydroepiandrosterone (DHEA) is a steroid that shows a marked age-related decline in humans. Previous research suggests potential for DHEA replacement in old age to enhance cognition and well-being. We conducted a clinical trial to test these hypotheses in a non-clinical sample of 46 men aged 62-76. Participants received either 50 mg DHEA daily for 13 weeks, followed by placebo for 13 weeks, or the reverse, in a randomised double-blind cross-over trial design. Levels of salivary cortisol and DHEA were measured at 0800 h and 2000 h prior to each assessment session. Cognition was assessed with tests of speed, attention and episodic memory. Well-being was measured with questionnaires of mood and perceived health. Mood questionnaires were completed at the assessment session as well as concurrently with saliva sampling.A correlational analysis of baseline behavioural data with hormonal data, controlling for age, revealed that higher morning DHEA was associated with lower confusion (r=-0.33; P=0.04), while higher evening DHEA was associated with lower anxiety (r=-0.35; P=0.03) and lower current negative mood in the morning (r=-0.37; P=0.03). Conversely, higher morning cortisol and a morning cortisol/DHEA ratio were associated with higher anxiety (r=0.35; P=0.03), (r=0.46; P=0.004), general mood disturbance (r=0.32; P=0.046), (r=0.32; P=0.04) and higher current negative mood in the evening (r=0.37; P=0.03), (r=0.38; P=0.03). A higher morning cortisol/DHEA ratio was also associated with higher confusion (r=0.39; P=0.01) and lower visuo-spatial memory performance (r=-0.39; P=0.01). Unexpectedly, higher evening cortisol was associated with faster choice reaction time (r=-0.33; P=0.04). These findings are consistent with an impairing effect of high cortisol on episodic memory and mood in older men, which may be attenuated by DHEA. When treatment effects were analysed, no significant effects of DHEA were observed on any of the trial outcomes, providing no support for benefits of DHEA supplementation for cognition or well-being in normal older men in the shorter-term.
Publication
Journal: Biochemistry
October/9/2007
Abstract
New approaches are required to combat Mycobacterium tuberculosis (Mtb), especially the multi-drug resistant and extremely drug resistant organisms (MDR-TB and XDR-TB). There are many reports that mycobacteria oxidize 3beta-hydroxysterols to 3-ketosteroids, but the enzymes responsible for this activity have not been identified in mycobacterial species. In this work, the Rv1106c gene that is annotated as a 3beta-hydroxysteroid dehydrogenase in Mtb has been cloned and heterologously expressed. The purified enzyme was kinetically characterized and found to have a pH optimum between 8.5 and 9.5. The enzyme, which is a member of the short chain dehydrogenase superfamily, uses NAD+ as a cofactor and oxidizes cholesterol, pregnenolone, and dehydroepiandrosterone to their respective 3-keto-4-ene products. The enzyme forms a ternary complex with NAD+ binding before the sterol. The enzyme shows no substrate preference for dehydroepiandrosterone versus pregnenolone with second-order rate constants (kcat/Km) of 3.2 +/- 0.4 and 3.9 +/- 0.9 microM-1 min-1, respectively, at pH 8.5, 150 mM NaCl, 30 mM MgCl2, and saturating NAD+. Trilostane is a competitive inhibitor of dehydroepiandrosterone with a Ki of 197 +/- 8 microM. The expression of the 3beta-hydroxysteroid dehydrogenase in Mtb is intracellular. Disruption of the 3beta-hydroxysteroid dehydrogenase gene in Mtb abrogates mycobacterial cholesterol oxidation activity. These data are consistent with the Rv1106c gene being the one responsible for 3beta-hydroxysterol oxidation in Mtb.
Publication
Journal: Journal of Biological Chemistry
April/23/2002
Abstract
Human organic anion transporting polypeptide 2 (OATP2/SLC21A6) and multidrug resistance-associated protein 2 (MRP2/ABCC2) play important roles in the vectorial transport of organic anions across hepatocytes. In the present study, we have established a double-transfected Madin-Darby canine kidney (MDCK II) cell monolayer, which expresses both OATP2 and MRP2 on basal and apical membranes, respectively. The basal-to-apical transport of 17 beta estradiol 17 beta-d-glucuronide (E(2)17 beta G), pravastatin, and leukotriene C(4) (LTC(4)), which are substrates of OATP2 and MRP2, was significantly higher than that in the opposite direction in the double-transfected cells. Such vectorial transport was also observed for taurolithocholate sulfate, which is transported by rat oatp1 and Mrp2. The K(m) values of E(2)17 beta G and pravastatin for the basal-to-apical flux were 27.9 and 24.3 microm, respectively, which were comparable with those reported for OATP2. Moreover, the MRP2-mediated export of E(2)17 beta G across the apical membrane was not saturated. In contrast, basal-to-apical transport of estrone-3-sulfate and dehydroepiandrosterone sulfate, which are significantly transported by OATP2, but not by MRP2, was not stimulated by MRP2 expression. The double-transfected MDCK II monolayer expressing both OATP2 and MRP2 may be used to analyze the hepatic vectorial transport of organic anions and to screen the transport profiles of new drug candidates.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
March/23/2005
Abstract
Previous studies have revealed that exogenous estrogen has a beneficial effect on the lipid profile; however, studies examining the relation between endogenous hormones and lipid profiles in postmenopausal women have yielded conflicting results. We sought to characterize the cross-sectional relationship between endogenous hormones and lipid parameters in postmenopausal women with significant (cases, n = 156) and minimal (controls, n = 172) carotid atherosclerosis not taking hormone therapy in the Atherosclerosis Risk in Communities Study. Endogenous hormone status was assessed by measuring levels of estrone, total testosterone, androstenedione, dehydroepiandrosterone sulfate, and SHBG. Free testosterone was estimated using the free androgen index (total testosterone/SHBG). Lipid parameters assessed included total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol. We found that SHBG was significantly associated with a more favorable lipid profile, including lower total and LDL cholesterol and triglycerides and higher HDL cholesterol among controls. This association was less prominent among cases where SHBG was only associated with higher triglycerides and lower HDL cholesterol. The free androgen index was associated with a more atherogenic lipid profile, including increased LDL cholesterol among controls and increased total and LDL cholesterol and triglycerides among cases. These relations were independent of demographic and metabolic factors and health behaviors. In contrast to controls, estrone was associated with higher total cholesterol and triglycerides among cases in multivariate analyses. Our data suggest that endogenous sex hormones may play a role in regulating lipid metabolism in postmenopausal women.
Publication
Journal: Journal of Neuroendocrinology
September/28/2006
Abstract
Berthold's classic study of domesticated roosters in 1849 demonstrated that testicular secretions are necessary for the normal expression of aggressive behaviour. Although this conclusion is undoubtedly correct, field studies of wild songbirds have yielded important modifications and limitations of Berthold's original hypothesis. For example, studies of the North American song sparrow (Melospiza melodia) during the breeding season reveal that not only does testosterone increase aggression, but aggressive interactions also increase plasma testosterone levels. Furthermore, in winter, nonbreeding song sparrows have low plasma testosterone levels but are very aggressive, and castration of nonbreeding song sparrows does not decrease aggression. Interestingly, an aromatase inhibitor (fadrozole) does decrease male aggression in the nonbreeding season, and the effects of fadrozole can be rescued with oestradiol. In winter, dehydroepiandrosterone (DHEA) from the periphery can be metabolised within the brain to supply oestradiol to specific neural circuits. Additionally, oestradiol might be synthesised de novo from cholesterol entirely within the brain. These mechanisms may have evolved to avoid the 'costs' of circulating testosterone in the nonbreeding season. Recent studies in tropical birds, hamsters, and humans suggest that these neuroendocrine mechanisms are important for the control of aggression in many vertebrate species.
Authors
Publication
Journal: Psychopharmacology
March/4/2014
Abstract
BACKGROUND
Stress has been shown to be a significant factor in the maintenance of marijuana use. Oxytocin is a hypothalamic neuropeptide that has been shown to moderate behavioral responding to stress as well as play a role in the neuroadaptations that occur as a consequence of long-term drug use.
OBJECTIVE
The current study evaluated the impact of oxytocin pretreatment on craving, stress, and anxiety responses following a psychosocial stress task in marijuana-dependent individuals.
METHODS
In a laboratory setting, baseline measurements of craving (assessed using the Marijuana Craving Questionnaire; MCQ), salivary cortisol and dehydroepiandrosterone (DHEA), stress, and anxiety were collected in 16 participants (age 19-40) meeting DSM-IV criteria for marijuana dependence. Participants were then administered either oxytocin 40 IU (n = 8) or placebo (n = 8) nasal spray prior to completion of the Trier Social Stress Task (TSST). Measurements were repeated pre-TSST, immediately post-TSST, and 5-, 35-, and 60-min post-TSST.
RESULTS
Oxytocin reduced both MCQ total score and DHEA levels from before to after the TSST. It also decreased anxiety, but not subjective stress ratings.
CONCLUSIONS
Although preliminary, these results suggest that oxytocin may play a role in the amelioration of stress-induced reactivity and craving in marijuana-dependent individuals.
Publication
Journal: Progress in Neurobiology
January/15/2004
Abstract
Estradiol, in addition to its participation in neuroendocrine regulation and sexual behavior, has neuroprotective properties. Different types of brain injury induce the expression of the enzyme aromatase in reactive astroglia. This enzyme catalyzes the conversion of testosterone and other C19 steroids to estradiol. Genetic or pharmacological inhibition of brain aromatase results in marked neurodegeneration after different forms of mild neurodegenerative stimuli that do not compromise neuronal survival under control conditions. Furthermore, aromatase mediates neuroprotective effects of precursors of estradiol such as pregnenolone, dehydroepiandrosterone (DHEA) and testosterone. These findings strongly suggest that local formation of estradiol in the brain is neuroprotective and that the induction of aromatase and the consecutive increase in the local production of estradiol are part of the program triggered by the neural tissue to cope with neurodegenerative insults. Aromatase may thus represent an important pharmacological target for therapies conducted to prevent aging-associated neurodegenerative disorders.
Publication
Journal: Biology of Reproduction
November/1/2004
Abstract
Equol (7-hydroxy-3[4'hydroxyphenyl]-chroman) is the major metabolite of the phytoestrogen daidzein, one of the main isoflavones found abundantly in soybeans and soy foods. Equol may be an important biologically active molecule based on recent studies demonstrating that equol can modulate reproductive function. In this study, we examined the effects of equol on prostate growth and LH secretion and determined some of the mechanisms by which it might act. Administration of equol to intact male rats for 4-7 days reduced ventral prostate and epididymal weight and increased circulating LH levels. Using binding assays, we determined that equol specifically binds 5alpha-dihydrotestosterone (DHT), but not testosterone, dehydroepiandrosterone, or estrogen with high affinity. Equol does not bind the prostatic androgen receptor, and has a modest affinity for recombinant estrogen receptor (ER) beta, and no affinity for ERalpha. In castrated male rats treated with DHT, concomitant treatment with equol blocked DHT's trophic effects on the ventral prostate gland growth and inhibitory feedback effects on plasma LH levels without changes in circulating DHT. Therefore, equol can bind circulating DHT and sequester it from the androgen receptor, thus altering growth and physiological hormone responses that are regulated by androgens. These data suggest a novel model to explain equol's biological properties. The significance of equol's ability to specifically bind and sequester DHT from the androgen receptor have important ramifications in health and disease and may indicate a broad and important usage for equol in the treatment of androgen-mediated pathologies.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
August/27/1997
Abstract
This study analyzes in detail the serum concentration of the active androgens and estrogens, as well as a series of free and conjugated forms of their precursors and metabolites, after daily application for 2 weeks of 10 mL 20% dehydroepiandrosterone (DHEA) solution on the skin to avoid first passage through the liver. In men, DHEA administration caused 175%, 90%, 200% and 120% increases in the circulating levels of DHEA and its sulfate (DHEA-S), DHEA-fatty acid esters, and androst-5-ene-3 beta,17 beta-diol, respectively, with a return to basal values 7 days after cessation of the 14-day treatment. Serum androstenedione increased by approximately 80%, whereas serum testosterone and dihydrotestosterone (DHT) remained unchanged. In parallel with the changes in serum DHEA, the concentrations of the conjugated metabolites of DHT, namely androsterone glucuronide, androstane-3 alpha,17 beta-diol-G, and androstane-3 beta,17 beta-diol-G increased by about 75%, 50%, and 75%, respectively, whereas androsterone-sulfate increased 115%. No consistent change was observed in serum estrone (E1) or estradiol (E2) in men receiving DHEA, whereas serum E1-sulfate and E2-sulfate were slightly and inconsistently increased by about 20%, and serum cortisol and aldosterone concentrations were unaffected by DHEA administration. Almost superimposable results were obtained in women for most steroids except testosterone, which was about 50% increased during DHEA treatment. This increase corresponded to about 0.8 nM testosterone, an effect undetectable in men because they already have much higher (approximately 15 nM) basal testosterone levels. In women, the serum levels of the conjugated metabolites of DHT, namely androsterone glucuronide, androstane-3 alpha,17 beta-diol-G, androstane-3 beta,17 beta-diol-G, and androsterone-sulfate were increased by 125%, 140%, 120% and 150%, respectively. The present study demonstrates that the serum concentrations of testosterone, DHT, E1, and E2 are poor indicators of total androgenic and estrogenic activity. However, the esterified metabolites of DHT appear as reliable markers of the total androgen pool, because they directly reflect the intracrine formation of androgens in the tissues possessing the steroidogenic enzymes required to transform the inactive precursors DHEA and DHEA-S into DHT. As well demonstrated in women, who synthesize almost all their androgens from DHEA and DHEA-S, supplementation with physiological amounts of exogeneous DHEA permits the biosynthesis of androgens limited to the appropriate target tissues without leakage of significant amounts of active androgens into the circulation. This local or intracrine biosynthesis and action of androgens eliminates the inappropriate exposure of other tissues to androgens and thus minimizes the risks of undesirable masculinizing or other androgen-related side effects of DHEA.
Publication
Journal: Langenbeck's Archives of Surgery
January/18/2006
Abstract
BACKGROUND
Several studies indicate that organ failure is the leading cause of death in the postoperative phase after major surgery. An excessive inflammatory response followed by a dramatic depression of cell-mediated immunity after major surgery appears to be responsible for the increased susceptibility to subsequent sepsis. In view of this, most of the scientific and medical research has been directed towards measuring the progression and interrelationship of mediators after major surgery. Furthermore, the effect of those mediators on cell-mediated immune responses has been studied.
OBJECTIVE
This article focuses on the effect of surgical injury and blood loss on cell-mediated immune responses in experimental studies utilizing models of trauma and hemorrhagic shock. The findings from those experimental studies will also be correlated with data from surgical patients.
RESULTS
Recently, a gender-dimorphic immune and organ responsiveness in the susceptibility to and morbidity from shock, trauma, and sepsis has been found. Androgens have been shown to be responsible for the immunosuppression after trauma-hemorrhage in males. In contrast, female sex steroids exhibit immunoprotective properties after trauma and severe blood loss.
CONCLUSIONS
In view of these findings, clinically relevant therapeutic strategies have been developed using the testosterone receptor blocker flutamide and/or estrogen or agents with estrogenic effects, i.e., dehydroepiandrosterone, which might yield safe and useful therapeutic approaches for the treatment of immune depression in surgical patients.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
October/6/2004
Abstract
To determine the relevance of polycystic ovarian morphology (PCOM) to the pathophysiology of polycystic ovarian syndrome (PCOS), biochemical features associated with PCOS were examined in 68 women with an established history of regular ovulatory cycles and no clinical evidence of hyperandrogenism. Ovarian morphology was objectively assessed by pelvic ultrasound. LH, FSH, estradiol (E(2)), testosterone (T), androstenedione (Delta(4)A), SHBG, and dehydroepiandrosterone sulfate (DHEAS) were measured at baseline in the early follicular phase (EFP) in all subjects. LH, FSH, E(2), and progesterone (P(4)) were then measured daily for a complete menstrual cycle in 16 women with normal ovarian morphology and in 26 women with PCOM. T, Delta(4)A, SHBG, and DHEAS levels were measured in pools of three daily samples in each of the EFP, midcycle, and midluteal phases. An additional 26 normal women (13 with normal ovarian morphology and 13 with PCOM) were studied in the EFP to assess pulsatile LH secretion, insulin and glucose levels, and the ovarian response to human chorionic gonadotropin. At baseline, there were no differences in body mass index or hirsutism scores between women with PCOM and normal ovaries. In daily samples across the menstrual cycle LH, FSH, E(2), and P(4) did not differ between women with PCOM and those with normal ovaries, and there was no difference in LH pulse amplitude or frequency in the EFP frequent sampling studies. In women with PCOM, T (P < 0.01), free T (P < 0.005), and DHEAS (P < 0.01) levels were higher at baseline in the EFP, and SHBG was lower (P < 0.05). Differences in Delta(4)A did not reach significance (P = 0.14). T, free T, Delta(4)A, and DHEAS were also increased in PCOM across the menstrual cycle (P < 0.05). In addition, 17-hydroxyprogesterone (P < 0.02), Delta(4)A (P < 0.01), and T (P < 0.01) responses to human chorionic gonadotropin were greater in women with PCOM. Fasting glucose was not different between the two groups, but fasting insulin was higher (P < 0.02) in PCOM women as was insulin resistance calculated from homeostatic model assessment (P < 0.01). These studies demonstrate that PCOM in nonhirsute women with documented ovulatory cycles is associated with normal E(2), P(4), and gonadotropin dynamics, but higher androgen and insulin levels and lower SHBG levels. Taken together, these findings suggest that PCOM with ovulatory cycles exists as a discrete entity, represents the mildest form of ovarian hyperandrogenism, and is associated with greater insulin resistance than in women with normal ovarian morphology. The absence of any neuroendocrine abnormality in women with PCOM and ovulatory cycles suggests that gonadotropin dysfunction is not required for increased androgen secretion, but may be critical for development of the anovulatory disorder associated with PCOS.
Publication
Journal: Bioorganic and Medicinal Chemistry
April/25/2012
Abstract
A novel naphthylmethylimidazole derivative 1 and its related compounds were identified as 17,20-lyase inhibitors. Based on the structure-activity relationship around the naphthalene scaffold and the results of a docking study of 1a in the homology model of 17,20-lyase, the 6,7-dihydro-5H-pyrrolo[1,2-c]imidazole derivative (+)-3c was synthesized and identified as a potent and highly selective 17,20-lyase inhibitor. Biological evaluation of (+)-3c at a dose of 1mg/kg in a male monkey model revealed marked reductions in both serum testosterone and dehydroepiandrosterone concentrations. Therefore, (+)-3c (termed orteronel [TAK-700]) was selected as a candidate for clinical evaluation and is currently in phase III clinical trials for the treatment of castration-resistant prostate cancer.
Publication
Journal: Reviews in Endocrine and Metabolic Disorders
March/16/2008
Abstract
Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders characterized by androgen excess, oligo-ovulation and polycystic ovaries. Although ovaries are the main source of increased androgens in the syndrome, between 20 and 30% of patients with PCOS have adrenal androgen (AA) excess, detectable primarily by elevated dehydroepiandrosterone sulfate (DHEAS) levels. Patients with PCOS demonstrate a generalized hypersecretion of adrenocortical products, basally and in response to ACTH stimulation. The mechanisms of these abnormalities are unclear although AA excess in PCOS is likely a complex trait, modulated by both intrinsic and acquired factors. To date, no specific genetic defects have been identified. The production of AAs in response to ACTH appears to be closely related to altered factors regulating glucose-mediated glucose disposal, increased peripheral metabolism of cortisol, and to a less extent to the effects of extra-adrenal androgens, insulin resistance, hyperinsulinemia or obesity. Finally, DHEAS levels and the response of AAs to ACTH are relatively constant over time and are closely correlated between PCOS patients and their siblings suggesting that this abnormality is an inherited trait in PCOS.
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