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Publication
Journal: Experimental Aging Research
March/23/1980
Abstract
The concentrations of blood serum steroids from 12 to <em>4</em>50 days old male rats were determined by radioimmunoassay. Testosterone (T) was low (270 pg to less than 1 ng/ml) until day <em>4</em>2; adult levels (3--<em>4</em> ng/ml) were attained by day 62 and declined tradually with advanced age. 5 alpha-dihydrotestosterone (5 alpha-DHT) did not change markedly (90--160 pg/ml) from prepubertal to advanced age. Except for a small peak on day 22, <em>androstenedione</em> (delta <em>4</em> A) levels ranged between <em>4</em>00-500 pg/ml in the adult but declined in older males. Progesterone (delta <em>4</em> P) rose steadily to a mean of 5.<em>4</em>6 ng/ml at 52 days of age and dropped thereafter. High levels of estrone (268 +/- 38 pg/ml) and estradiol-17 beta (2.76 +/- 0.28 ng/ml) in 12 days old males are in contrast to the low estrogens (20-35 pg/ml) in adult animals. Both T/5 alpha-DHT and total T/estrogen ratios were low before puberty, increased in adults and decreased towards old age. The interplay between gonadotropin and prolactin, which exhibited reciprocal changes in the regulation of steroid production by the gonads with age, are discussed.
Publication
Journal: European Neuropsychopharmacology
April/30/2006
Abstract
OBJECTIVE
The goals of this study were to determine whether alterations in serum dehydroepiandrosterone (DHEA), its sulfated conjugate (DHEAS), androstenedione, testosterone, and progesterone concentrations occur in schizophrenia patients compared with healthy controls over two months, and their associations with psychopathology, emotional distress, and antipsychotic treatment.
METHODS
Serum hormones were repeatedly determined for 21 antipsychotic-treated male DSM-IV schizophrenia patients and 14 healthy controls. Observations were at four time points: upon entry into the study, and after 2, 4 and 8 weeks.
RESULTS
In schizophrenia patients compared with healthy controls serum concentration of DHEA and androstenedione found increased, but that of DHEAS decreased, while progesterone and testosterone showed normal levels. Schizophrenia patients were also characterized by elevated androstenedione/DHEAS molar ratios, and reduced DHEAS/DHEA and testosterone/androstenedione molar ratios compared with healthy controls. Concentrations and molar ratios of serum hormones did not significantly change during the study either among schizophrenia patients, or healthy controls. Among patients alterations in DHEA, DHEAS and androstenedione were associated with emotional distress, anxiety, dysphoric mood, positive and activation symptoms, serum prolactin levels, but were not related to age, antipsychotic agents, and extrapyramidal side effects.
CONCLUSIONS
Alterations in DHEA metabolism in schizophrenia are attributed to the distress, anxiety, severity of symptoms, prolactin levels, and may represent a marker for impaired hormonal responses to stress. These findings should be considered when evaluating the discrepancies in DHEA studies in schizophrenia.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
January/30/1996
Abstract
The administration of long-acting GnRH analogs (GnRH-a) results in gonadotropin and androgen suppression in hyperandrogenic women. Nonetheless, no randomized studies are available comparing GnRH-a with currently used treatments for hirsutism. We have hypothesized that the greater degrees of androgen suppression achieved with GnRH-a therapy could result in a more rapid improvement in hirsutism compared to oral contraceptive (OCP) administration. To test this hypothesis, we studied 17 hirsute women before and during 6 months of randomized treatment with 1) leuprolide depot (3.75 mg/month) plus conjugated estrogen (0.625 mg/day) and medroxyprogesterone acetate (10 mg; days 1-12; n = 9; leuprolide+ERT), or 2) an OCP containing ethynodiol diacetate (1 mg) and ethinyl estradiol (35 micrograms; n = 8). LH, FSH, estradiol, dehydroepiandrosterone sulfate, <em>androstenedione</em> (A<em>4</em>), sex steroid-binding globulin, and total and free testosterone (T) were measured at weeks 0, 2, <em>4</em>, 8, 12, and 28. At 0 and 28 weeks of treatment, hirsutism was evaluated subjectively by patient self-evaluation and by the Ferriman-Gallwey score, and objectively by determination of facial hair density, outer hair shaft diameter, and growth rate, determined both photographically and in plucked hairs. In the leuprolide+ERT, but not OCP, groups, there was a significant decrease in the circulating LH and FSH levels. In both groups, T and A<em>4</em> decreased with treatment, although the decrease in A<em>4</em> levels did not reach significance in OCP-treated women. The circulating sex steroid-binding globulin level increased in both treatment groups, but the changes in the OCP-treated women was greater. Consequently, although the calculated percent free T decreased significantly in both treatment groups, the decrease was greater in the OCP-treated women. The dehydroepiandrosterone sulfate level did not change with either therapy. A significant percent decrease in the Ferriman-Gallwey score was noted in the leuprolide+ERT, but not OCP, patients, and by self-evaluation, seven (78%) and five (55%) of leuprolide+ERT patients, compared to two (25%) and two (25%) OCP-treated women, noted an improvement in hair growth and texture, respectively. No significant difference in mean facial hair density or outer hair diameter was noted with either therapy. Patients treated with leuprolide+ERT demonstrated a decrease in the actual hair growth rate, using the photographic method, or percent decrease in growth rate, using plucked hair. In conclusion, treatment with leuprolide plus cyclic estrogen/progestin appears to provide a more rapid, and possibly greater, improvement in hirsutism, compared to a standard OCP regimen.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication
Journal: Biology of Reproduction
December/1/1986
Abstract
Pieces of theca interna or follicle wall (theca interna + attached granulosa cells), obtained from bovine preovulatory follicles prior to the surge of luteinizing hormone (LH) and cultured for 3 days, secreted <em>androstenedione</em>. Luteinizing hormone, but not follicle-stimulating hormone (FSH), increased production of <em>androstenedione</em> 3 to <em>4</em>-fold. In both the presence and absence of LH, follicle wall preparations secreted about <em>4</em>-fold more <em>androstenedione</em> than did equivalent amounts of theca interna tissue. Isolated granulosa cells produced only negligible quantities of <em>androstenedione</em>, which suggests that they may contribute to the greater production of <em>androstenedione</em> by follicle wall by supplying progestin precursor to the theca cells. The addition of pregnenolone or progesterone to isolated theca interna increased the secretion of <em>androstenedione</em>, but pregnenolone was by far the more effective precursor. This suggested that the delta 5 (delta 5) pathway is the preferred pathway for <em>androstenedione</em> synthesis by bovine theca cells and that granulosa cells might supply progestin precursor in the form of pregnenolone. Follicle wall and granulosa cell cultures secreted 2 and 7 times more pregnenolone, respectively, than did theca cultures. Luteinizing hormone, but not FSH, increased production of pregnenolone by the follicle wall, whereas the gonadotropins had no effect on secretion by either granulosa or theca cells. Since exogenous testosterone enhanced the production of pregnenolone by granulosa cells, thecal androgen (which is stimulated by LH) may increase the ability of granulosa cells to make pregnenolone and explain the stimulatory effect of LH on pregnenolone secretion by follicle wall.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
March/12/1982
Abstract
To elucidate the controversial point whether, in analogy with delta 5-steroid secretion, adrenal delta <em>4</em>-steroid secretion is significantly decreased in elderly persons, we studied the response of plasma levels of both delta 5-steroids (dehydroepiandrosterone, 17-hydroxypregnenolone, and pregnenolone) and delta <em>4</em>-steroids (cortisol, <em>androstenedione</em>, 17-hydroxyprogesterone, and progesterone) to acute ACTH stimulation in four groups of young and elderly males and females, respectively. To study the possible influence of sex hormones on adrenocortical function in elderly persons, we performed the same study in male with prostatic carcinoma treated with estrogens. The data show that in elderly persons, the response of plasma delta <em>4</em>-steroids to ACTH stimulation is comparable or higher than that in young subjects, whereas the response of delta 5-steroids is significantly decreased; estrogen treatment does not change this pattern. It is concluded that in elderly persons adrenal delta <em>4</em>-steroid secretory capacity is unimpaired, whereas delta 5-steroid secretion is significantly decreased. The responsible mechanism remains to be elucidated.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
April/4/1993
Abstract
We have previously shown that the proliferative index (PI), as determined by flow cytometry of luteinized granulosa cells obtained at oocyte retrieval, is greater in ovulation induction regimens which include the GnRH analog (GnRH-a) leuprolide acetate than those using human menopausal gonadotropin (hMG) only. Specific growth factors or intrafollicular hormones may contribute to this leuprolide acetate-induced difference in cell cycle kinetics. We examined whether differences in the PI of these granulosa cells are associated with the alterations of follicular fluid content of Mullerian-inhibiting substance (MIS) and other intrafollicular hormones including FSH, estradiol, progesterone, <em>androstenedione</em>, and testosterone. The control group consisted of follicular fluid obtained from 18 follicles from <em>4</em> women receiving hMG alone. The GnRH-a treated group consisted of follicular fluids obtained from 55 follicles aspirated from 18 women receiving GnRH-a in addition to hMG. One-way analysis of variance using log-transformed data and expressed as geometric means with 95% confidence intervals, demonstrated that the follicles from the control group had a significant 1<em>4</em>-fold higher concentration of 2.<em>4</em>6 ng/mL MIS, 95% CI (1.8-<em>4</em>.8) vs. 0.18 ng/mL, 95% CI (0.13-0.2<em>4</em>) P < 0.0005, a 3-fold higher concentration of 17.55 nmol/L <em>androstenedione</em>, 95% CI (1<em>4</em>.6-20.9) vs. 5.76 nmol/L, 95% CI (3.1-10.5) P < 0.02, and a 1.5-fold higher concentration of 29.<em>4</em>3 nmol/L testosterone 95% CI (22.5-38.1<em>4</em>) vs. 19.3 nmol/L, 95% of CI (11.1-33.9) P < 0.01 than GnRH-a treated follicles, although the PI value in controls was half that of the GnRH-a group. These data demonstrate that GnRH-a induced differences in granulosa cell cycle kinetics are associated with alterations of MIS and androgen intrafollicular fluid content and suggest that MIS may be a mitotic inhibitor of human granulosa cells.
Publication
Journal: Archives of Biochemistry and Biophysics
June/30/1994
Abstract
A fusion protein containing the heme domain of bovine cytochrome P<em>4</em>50 17A and the flavin domains of rat NADPH-cytochrome P<em>4</em>50 reductase has been genetically engineered by linking the modified cDNAs for each gene with the codons for serine and threonine. Transformation of Escherichia coli (DH5 alpha) and growth under defined conditions permits expression of 600-700 nmol of membrane-bound fusion protein per liter of growth medium (approximately <em>4</em>% of cellular protein). A method has been developed for the solubilization, isolation, and purification to homogeneity of this protein. In the presence of NADPH the purified fusion protein catalyzes the 17 alpha-hydroxylation of progesterone and pregnenolone as well as the conversion of 17 alpha-hydroxypregnenolone to dehydroepiandrosterone. The 17,20-lyase activity is enhanced sixfold by the addition of purified rat liver cytochrome b5. Further, dehydroepiandrosterone is slowly metabolized to a number of additional more polar metabolites while 17 alpha-hydroxy-progesterone is slowly converted to dihydroxy-progesterone metabolites as well as a small amount of <em>androstenedione</em> in a reaction not influenced by cytochrome b5. Use of 5 alpha-pregnan steroids as substrates show the importance of the 3 beta-hydroxyl group for cytochrome b5 stimulated 17,20-lyase activity. Studies investigating the factors affecting electron transport between the flavin and heme domains suggest that the protein exists as a tight complex functioning as a self-contained biocatalytic unit.
Publication
Journal: Journal of steroid biochemistry
January/17/1989
Abstract
In human pregnancy, placental 3 beta-hydroxy-5-ene-steroid dehydrogenase and steroid 5----<em>4</em>-ene-isomerase produce progesterone from pregnenolone and metabolize fetal dehydroepiandrosterone sulfate to <em>androstenedione</em>, an estrogen precursor. The enzyme complex was solubilized from human placental microsomes using the anionic detergent, sodium cholate. Purification (500-fold, 3.9% yield) was achieved by ion exchange chromatography (Fractogel-TSK DEAE 650-S) followed by hydroxylapatite chromatography (Bio-Gel HT). The purified enzyme was detected as a single protein band in sodium dodecylsulfate-polyacrylamide gel electrophoresis (monomeric Mr = 19,000). Fractionation by gel filtration chromatography at constant specific enzyme activity supported enzyme homogeneity and determined the molecular mass (Mr = 76,000). The dehydrogenase and isomerase activities copurified. Kinetic constants were determined at pH 7.<em>4</em>, 37 degrees C for the oxidation of pregnenolone (Km = 1.9 microM, Vmax = 32.6 nmol/min/mg) and dehydroepiandrosterone (Km = 2.8 microM, Vmax = 32.0 nmol/min/mg) and for the isomerization of 5-pregnene-3,20-dione (Km = 9.7 microM, Vmax = 618.3 nmol/min/mg) and 5-androstene-3,17-dione (Km = 23.7 microM, Vmax = 625.7 nmol/min/mg). Mixed substrate analyses showed that the dehydrogenase and isomerase reactions use the appropriate pregnene and androstene steroids as alternative, competitive substrates. Dixon analyses demonstrated competitive inhibition of the oxidation of pregnenolone and dehydroepiandrosterone by both product steroids, progesterone and <em>androstenedione</em>. The enzyme has a 3-fold higher affinity for <em>androstenedione</em> than for progesterone as an inhibitor of dehydrogenase activity. Based on these competitive patterns of substrate utilization and product inhibition, the pregnene and androstene activities of 3 beta-hydroxy-5-ene-steroid dehydrogenase and steroid 5----<em>4</em>-ene-isomerase may be expressed at a single catalytic site on one protein in human placenta.
Publication
Journal: Domestic Animal Endocrinology
February/28/2005
Abstract
To determine if (1) levels of pregnancy-associated plasma protein-A (PAPP-A) mRNA and insulin-like growth factor binding protein (IGFBP) (-2, -3, -<em>4</em> and -5) mRNAs differ between the dominant and subordinate follicles during the follicular phase of an estrous cycle, and (2) these differences are associated with differences in follicular fluid (FFL) concentrations of steroids (estradiol, <em>androstenedione</em>, and progesterone), total and free IGF-I, or IGFBPs, estrous cycles of non-lactating Holstein dairy cows (n = 16) were synchronized with two injections of prostaglandin (PGF2 alpha) 11 days apart. Granulosa cells and FFL were collected either 2<em>4</em> h or <em>4</em>8 h after the second injection of PGF2 alpha. FFL from dominant follicles had lower concentrations of progesterone (P < 0.08) and higher concentrations of estradiol (P < 0.05), <em>androstenedione</em> (P < 0.0001), estradiol:progesterone ratio (P < 0.0001), free IGF-I (P < 0.0001), and calculated percentage free IGF-I (P < 0.01) than large subordinate follicles. Levels of IGFBP-2, -<em>4</em>, and -5 in FFL were 3.0- (P < 0.05), 2.<em>4</em>- (P < 0.06), and 3.<em>4</em>-fold (P < 0.05) greater, respectively, in subordinate than in dominant follicles. IGFBP-3, IGFBP-<em>4</em> and PAPP-A mRNA expression and IGF-II concentration did not differ (P>> 0.10) between dominant or subordinate follicles. Levels of IGFBP-2 and -5 mRNA were severalfold greater (P < 0.05) in subordinate than dominant follicles. IGFBP-5 mRNA in granulosa cells decreased (P < 0.05) 62% to 92%, between 2<em>4</em>h and <em>4</em>8 h post-PGF2 alpha. We conclude that decreased levels of IGFBP-2 and -5 mRNA in granulosa cells may contribute to the decrease in FFL IGFBP-2 and -5 protein levels of preovulatory dominant follicles, and that changes in granulosa cell IGFBP-3 and -<em>4</em> mRNA and PAPP-A mRNA levels do not occur during final preovulatory follicular development in cattle.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
August/28/1975
Abstract
ACTH dependency of plasma <em>androstenedione</em> (A) and testosterone (T) was determined in normal and hirsute women by measuring the magnitude of change of A and T between the time of the cortisol (F) peak and F nadir in a diurnal study. There was a significant diurnal rhythm of A synchronous with F in both normal and hirsute women (P less than 0.01). Five of 12 hirsute women had a greater than normal diurnal swing of A (P less than 0.05), but only 2 of the 12 had a greater than normal diurnal swing of T. Responsiveness of A and T to 1/2 unit of intravenous ACTH was determined after dexamethasone 1 mg was given the night before. Plasma A and T were elevated in most of the hirsute women during acute ACTH suppression by dexamethasone, indicating ACTH-independent hypersecretion of androgens. Nine of 17 hirsute women had a greater than normal A response to ACTH (P less than 0.05). Those who had an exaggerated diurnal swing of A also had hyper-responsiveness of A secretion to ACTH. Only 2 hirsute women had an exaggerated T response to ACTH. Some T levels were decreased by ACTH. Seven of the 9 hiruste women who had an exaggerated A response to ACTH had a normal maximum F response, but a greater than normal 17-hydroxy-progesterone (17-OHP) response to ACTH with a high 17-OHP to F ratio, suggesting they have a mild but compensated reduction in 21-hydroxylase or 11beta-hydroxylase activity. Two women with hyper-responsiveness of A secretion had low F and 17-OHP responses to ACTH suggesting reduced C21 but intact C19 3beta-hydroxysteroid dehydrogenase-delta-5,-<em>4</em> isomerase activity. These apparent reduced enzyme activity may not be congenital, but induced by an altered hormonal milieu such as an abnormal androgen-estrogen ratio. It is concluded that ACTH uniformly stimulated A secretion but not T secretion and that approximately 50% of the hirsute women had ACTH-dependent hypersecretion of A, but most of these also had concurrent ACTH-independent hypersecretion of androgens.
Publication
Journal: Biology of Reproduction
December/20/1999
Abstract
We have investigated the possible role of theca and granulosa cell interaction in the control of the hormone-producing activity and growth of granulosa and theca cells during bovine ovarian follicular development, using a coculture system in which granulosa and theca cells were grown on opposite sides of a collagen membrane. When follicular cells were isolated from small follicles (3-5 mm), theca cells reduced estradiol, progesterone, and inhibin production by granulosa cells to 1<em>4</em> +/- 5%, 6<em>4</em> +/- 6%, and 27 +/- <em>4</em>%, respectively, of the production by granulosa cells cultured alone. On the other hand, when the cells were isolated from large follicles (15-18 mm), theca cells increased these levels to 253 +/- 3<em>4</em>%, 156 +/- 2<em>4</em>%, and 287 +/- <em>4</em>5%, respectively. Theca cells did not affect the growth of granulosa cells. <em>Androstenedione</em> production by theca cells was augmented by granulosa cells to 861 +/- 190% (in small follicles) and 1298 +/- <em>4</em>1<em>4</em>% (in large follicles), respectively. The growth of theca cells was also augmented by granulosa cells (small follicle, 210 +/- <em>4</em>3%, and large follicle, 19<em>4</em> +/- 2<em>4</em>%, respectively). These results indicate that theca cells secrete factor(s) inhibiting the differentiation of immature while promoting that of matured granulosa cells; they also suggest that granulosa cells secrete factor(s) promoting both the differentiation and growth of theca cells throughout the follicular maturation process.
Publication
Journal: International Journal of Sport Nutrition and Exercise Metabolism
November/6/2000
Abstract
The effects of androgen precursors, combined with herbal extracts designed to enhance testosterone formation and reduce conversion of androgens to estrogens was studied in young men. Subjects performed 3 days of resistance training per week for 8 weeks. Each day during Weeks 1, 2, <em>4</em>, 5, 7, and 8, subjects consumed either placebo (PL; n = 10) or a supplement (ANDRO-6; n = 10), which contained daily doses of 300 mg <em>androstenedione</em>, 150 mg DHEA, 750 mg Tribulus terrestris, 625 mg Chrysin, 300 mg Indole-3-carbinol, and 5<em>4</em>0 mg Saw palmetto. Serum <em>androstenedione</em> concentrations were higher in ANDRO-6 after 2, 5, and 8 weeks (p <.05), while serum concentrations of free and total testosterone were unchanged in both groups. Serum estradiol was elevated at Weeks 2, 5, and 8 in ANDRO-6 (p <.05), and serum estrone was elevated at Weeks 5 and 8 (p <.05). Muscle strength increased (p <.05) similarly from Weeks 0 to <em>4</em>, and again from Weeks <em>4</em> to 8 in both treatment groups. The acute effect of one third of the daily dose of ANDRO-6 and PL was studied in 10 men (23 +/- <em>4</em> years). Serum <em>androstenedione</em> concentrations were elevated (p <.05) in ANDRO-6 from 150 to 360 min after ingestion, while serum free or total testosterone concentrations were unchanged. These data provide evidence that the addition of these herbal extracts to <em>androstenedione</em> does not result in increased serum testosterone concentrations, reduce the estrogenic effect of <em>androstenedione</em>, and does not augment the adaptations to resistance training.
Publication
Journal: Cancer Letters
March/20/1994
Abstract
The inhibition of estrogen biosynthesis by the use of aromatase inhibitors is emerging as a valuable approach to breast cancer therapy. Because smoking has a profound effect on estrogen-related processes we examined the ability of tobacco constituents to suppress estrogen production by breast cancer aromatase. N-n-octanoylnornicotine and N-(<em>4</em>-hydroxyundecanoyl) anabasine suppressed aromatase activity in culture of two human breast cancer cell lines, MDA-MB-231 (IC50 of 310 and 20 microM, respectively) and SK-BR-3 (IC50 of <em>4</em>50 and approximately 2 microM, respectively). MDA-MB-231 cells induced by 250 nM dexamethasone or 1 mM (Bt)2cAMP were slightly more sensitive to both inhibitors. Kinetic analyses showed that inhibition by N-(<em>4</em>-hydroxyundecanoyl)anabasine is competitive with respect to <em>androstenedione</em> as substrate, with apparent Ki values of 0.2 microM against microsomal aromatase activity derived from both (Bt)2cAMP-induced MDA-MB-231 cells and human breast tumor tissue. The corresponding apparent Ki against human placental microsomal aromatase activity was 0.<em>4</em> microM. These results indicate that acyl derivatives of nornicotine and anabasine block estrogen formation in breast tumor cells and tissue and could contribute to the decreased intra-tissue estrogen levels in women who smoke.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
August/27/1997
Abstract
The physiological importance and therapeutical interest of dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) are still controversial. Panhypopituitarism is characterized by the absence of secretion of adrenal and gonadal steroids and thus the production of their metabolites. The conversion of DHEA given orally into delta 5 derivatives, androgens, androgen metabolites, and estrogens was studied in ten patients with complete panhypopituitarism. Sex steroid therapy was withdrawn for at least 2 months. Each patient received, at 1-month intervals and in a random order, two single oral doses of DHEA (50 mg and 200 mg) and placebo. During each treatment, urine samples were collected for 2<em>4</em> h, and blood samples were drawn at hourly intervals for 8 h. In patients with pituitary deficiency, plasma DHEA and DHEAS were not detectable and increased, with the 50 mg dose, up to levels observed in young adults. The administration of 200 mg of DHEA induced an increase of both steroids to supraphysiological plasma levels. A small increase of delta 5-androstenediol was observed. In contrast, the increase of plasma delta <em>4</em>-<em>androstenedione</em> was important and dose dependent. DHEA was also converted into the potent sex steroid testosterone (T). The administration of a 50 mg dose of DHEA restored plasma T to levels similar to those observed in young women. The 200 mg dose induced an important increase of plasma T, slightly below the levels observed in normal men. The increase of plasma dihydrotestosterone levels was small at both doses of DHEA, in contrast with the large conversion of DHEA into androsterone glucuronide and androstanediol glucuronide. Finally, DHEA administration induced a significant and dose dependent increase of plasma estrogens and particularly of estradiol. In conclusion, this short term study demonstrates that: 1) panhypopituitarism is a model of interest to study the metabolism of DHEA; 2) in the absence of pituitary hormones and of adrenal and gonadal steroids, DHEA given orally is mainly converted into delta <em>4</em> derivatives, which in turn are strongly metabolized into 5 alpha-3keto-reduced steroids; 3) a significant increase of sex active hormones was observed in plasma after 200 and even 50 mg of DHEA. Thus, biotransformation of DHEA into potent androgens and estrogens may explain several of the reported beneficial actions of this steroid in aging people.
Publication
Journal: Breast Cancer Research and Treatment
December/3/1995
Abstract
One hundred and twelve post menopausal or post oophorectomy women with advanced breast cancer (BC) who had all previously had aminoglutethimide (AG) were treated with the potent aromatase inhibitor <em>4</em>-hydroxy <em>androstenedione</em> (<em>4</em>-OHA). Twenty three women (21%) had a partial response to <em>4</em>-OHA while another twenty five patients (22%) had stabilization of previously progressing disease. Patients responded to <em>4</em>-OHA both after previously responding to then relapsing on, and after failing to respond to aminoglutethimide. Toxicity was minimal. This study shows that potent aromatase inhibition with <em>4</em>-OHA is effective in women with advanced BC who have already been treated with a less potent aromatase inhibitor, and suggests that relative changes in oestrogen levels may be more important than absolute levels.
Publication
Journal: Fertility and Sterility
February/28/2005
Abstract
OBJECTIVE
Assessment of ovarian responses to metformin treatment in obese women with polycystic ovary syndrome (PCOS).
METHODS
Prospective treatment with randomization to two doses of metformin.
METHODS
University teaching hospital.
METHODS
Obese women (n = 82) with PCOS.
METHODS
Markers of ovarian function were assessed after <em>4</em> and 8 months.
METHODS
Hormone (androgens and mullerian-inhibiting substance [MIS]) changes over time.
RESULTS
There was no difference in the reproductive hormone changes between the doses of metformin, and data were combined for further analyses. Significant responses to treatment were recorded for menstrual frequency and androstenedione (A) (reduction) within the first <em>4</em> months of treatment. However, suppression of the elevated circulating MIS concentrations required protracted treatment, because no change was observed in the first <em>4</em> months-only in the second <em>4</em>-month assessment period.
CONCLUSIONS
Metformin treatment of PCOS leads to rapid suppression of A and improved menstrual frequency. Suppression of MIS is a delayed response that may be secondary to the development of a cohort of follicles that underwent initial recruitment in an environment of reduced insulin stimulation.
Publication
Journal: Rapid Communications in Mass Spectrometry
March/7/2005
Abstract
A function of concentrations of three ketosteroids, [(<em>androstenedione</em> + 17alpha-hydroxyprogesterone)/cortisol], has been shown to provide better discrimination than the concentration of 17alpha-hydroxyprogesterone alone, for the diagnosis of the inherited disease congenital adrenal hyperplasia (CAH). A rapid, direct infusion electrospray ionization tandem mass spectrometry (ESI-MS/MS) method has been developed to measure this ratio in plasma (100 microL). Sensitivity and specificity result from the preparation of mono-Girard T derivatives. <em>Androstenedione</em>, 17alpha-hydroxyprogesterone and cortisol are individually quantitated by isotope dilution. Excellent statistical correlation with radioimmunoassay (RIA) results for the analysis of 17alpha-hydroxyprogesterone is demonstrated. The value of the ratio function of the three ketosteroids is 0.01-0.16 for normal controls (n=26) and 1.83-18.7 for patients with severe CAH (n=<em>4</em>). Profiles of ketosteroids derivatized with Girard T from the plasma of a child with severe CAH, generated by ESI-MS/MS analysis, are shown. Neutral loss scans for 29.5 and 59 Da assist in the identification of the ketosteroids.
Publication
Journal: Human Reproduction
September/20/1999
Abstract
The aim of this study was to examine the echocardiographic profiles of patients with polycystic ovarian syndrome (PCOS). Serum concentrations of follicle stimulating hormone, luteinizing hormone, <em>androstenedione</em>, free testosterone, prolactin, DHEA-SO(<em>4</em>) and 17-OH-progesterone, lipid profile (high and low density lipoproteins, triglyceride and total cholesterol) and basal and total insulin after a glucose tolerance test were measured in 35 patients with PCOS and 35 healthy controls matched for body mass index. Doppler, two dimensional M mode echocardiography was performed for the following indices: isovolumetric relaxation time (IVRT), E wave duration time (EVT), A wave duration time (AVT), E wave deceleration time (DT), peak early diastolic flow velocity (PEV), peak late diastolic flow velocity (PAV), E wave velocity time integral (FVI-E), A wave velocity time integral (FVI-A), atrial filling fraction (AFF), ejection fraction (EF), pre-ejection time (PEP), ejection time (ET) and aortic flow velocity time integral (FVI). <em>Androstenedione</em>, free testosterone, low density lipoproteins and cholesterol concentrations were significantly higher in patients with PCOS. There was no difference in basal and total insulin concentrations. IVRT, AVT, FVI-A, AFF, and PEP were higher in patients with PCOS, while PEV, FVI-E, EF, ET, EVT and EVT/AVT were higher in the control group. There was a positive correlation between basal insulin values and IVRT, and between total insulin values and EF. These changes are consistent with a non-restrictive type of diastolic dysfunction and left ventricular stiffness. PCOS may lead to diastolic dysfunction via hyperinsulinaemia and male type dyslipidaemia.
Publication
Journal: Toxicology
January/6/1999
Abstract
Methapyrilene (MP) is an unusual hepatotoxin in that it causes periportal necrosis in rats. The mechanism of acute methapyrilene hepatotoxicity has, therefore, been investigated in cultured male rat hepatocytes. Addition of methapyrilene to rat hepatocytes resulted in a time- and dose-dependent loss in cell viability between <em>4</em> and 8 h of incubation as judged by cellular enzyme leakage. The cytochrome P<em>4</em>50 (CYP) inhibitor metyrapone protected against methapyrilene-mediated toxicity suggesting that MP is metabolised by CYP for toxicity. The concentration-dependent protection from methapyrilene toxicity afforded by metyrapone correlated with an inhibition of microsomal CYP2C11-associated <em>androstenedione</em> 16alpha hydroxylase activity, and hepatocytes prepared from hypophysectomised rats (containing reduced levels of microsomal immunodetectable CYP2C11 and associated <em>androstenedione</em> 16alpha hydroxylase activity) showed resistance to the toxic effects of methapyrilene. These data suggest that the toxicity of methapyrilene is predominantly dependent on the CYP2C11 isoform. Treatment of hepatocytes with a toxic concentration of MP caused oxidative stress as indicated by increases in NADP+ levels within 2 h and cellular thiol oxidation as evidenced by a reduction--but not complete loss--in glutathione levels. Methapyrilene hepatotoxicity was associated with an early loss in mitochondrial function, as indicated by mitochondrial swelling and significant losses in cellular ATP within 2 h. Co-incubation of methapyrilene-treated hepatocytes with inhibitors of inner mitochondrial transition permeability pore opening--cyclosporin A or the thiol reductant dithiothreitol--abrogated cell death suggesting that pore opening and loss of mitochondrial Ca2+ homeostasis play a significant role in methapyrilene-mediated cell death. Co-incubation of methapyrilene-treated hepatocytes with the phenylalkylamine calcium channel blocker verapamil--but not by treating cells in a nominally calcium-free medium--also abrogated cell death, suggesting that if Ca2+ is involved in cell killing then it is dependent on an intracellular Ca2+ pool. Pre-treatment of hepatocytes for 1 h with verapamil--to inhibit intracellular Ca2+ pool filling--increased the potency of verapamil protection against methapyrilene toxicity by approximately 100-fold. Taken together, these data indicate that methapyrilene intoxication leads to mitochondrial disfunction and suggest a critical role for a loss of mitochondrial Ca2+ homeostasis in this model of hepatocyte death.
Publication
Journal: Acta Endocrinologica
January/28/1981
Abstract
Three healthy males (18, 22 and 30 years of age; 85 kg/177 cm, 82 kg/181 cm and 75 kg/168 cm, respectively), synchronized with a diurnal activity (06.00 to 23.00 h) and nocturnal rest, volunteered for this study. Blood was sampled (venous catheter) hourly during a 2<em>4</em> h span. A radiocompetition method was used for cortisol determinations. Other steroids were first extracted (ethyl-ether) from each plasma sample, then chromatographed on a celite column to isolate 3 fractions: 1) delta <em>4</em>-<em>androstenedione</em> (delta-<em>4</em>); 2) dihydrotestosterone (DHT) and dehydroepiandrosterone (DHA); 3) testosterone (T). A radioimmunological assay was used thereafter for the determination of androgenic steroids. Statistically significant (both conventional and cosinor methods) circadian rhythms were detected (P>> 0.005). Acrophases (peak times) occurred in the following order: cortisol (07.28), DHA (08.<em>4</em>3), delta-<em>4</em> (09.5<em>4</em>), T (11.15) and DHT (16.37). The respective circadian amplitudes of DHA and delta-<em>4</em> were smaller than those of cortisol while the amplitudes T and DHT did not show differences statistically significant from each other.
Publication
Journal: Biology of Reproduction
February/17/1994
Abstract
Progesterone induces maturation of the amphibian oocyte through its action on the plasma membrane. However, whether or not this action requires high-affinity binding to a specific receptor is unclear. In this study, the binding activity of progesterone was characterized in plasma membranes from whole ovaries or defolliculated oocytes of Xenopus laevis. Membrane-bound, radiolabeled progesterone was isolated by filtration of membrane suspensions and quantified by liquid scintillation. The association of progesterone to membrane preparations reached equilibrium within 15 min. Progesterone binding activity was directly proportional to the sample concentration, was significantly reduced by trypsin digestion, and was pH-dependent and temperature-sensitive. Also, binding activity was observed in membrane preparations from whole ovaries and defolliculated oocytes but not in those from somatic cells, indicating that progesterone binding is restricted to the oocyte membrane. Scatchard analysis indicated a single class of high-affinity (average KD, 10(-9) M), low-capacity (average concentration, 10(-12) mol/mg protein) binding sites for progesterone in all oocyte membrane preparations tested. Progesterone binding activity was also detected in preparations from albino frog ovaries, indicating that the binding activity is not an artifact of melanin contamination. Competition studies showed the following order of affinities: progesterone>> pregnenolone>> 17 alpha, 20 beta, 21-trihydroxy-<em>4</em>-pregnen-3-one>> 11-deoxycorticosterone>> 17 alpha, 20 beta-dihydroxy-<em>4</em>-pregnen-3-one>> 11-deoxycortisol>> estradiol>> R5020>> corticosterone>> aldosterone>> cortisol>> <em>androstenedione</em>>> ouabain.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication
Journal: Steroids
February/14/1980
Abstract
The ability of granulosa and theca cells of the human ovarian follicle at different stages of development, as well as stromal and luteal tissues from human ovaries to metabolize <em>androstenedione</em> (delta <em>4</em>) to testosterone (T), dihydrotestosterone (DHT), estrone (E1) and estradiol (E2) with or without exposure to additional amounts of folicle-stimulating hormone was investigated by in vitro experiments. The results show that all the aforementioned ovarian tissues metabolized delta <em>4</em> to DHT. Indeed, with the exception of estrogen-secreting granulosa cells from large antral follicle (greater than 10 mm diameter) and possibly also luteal tissue from mid-luteal phase ovaries, the various ovarian tissues preferentially metabolized delta <em>4</em> to DHT instead of E (E1 + E2). Although thecal tissue is a major source of delta <em>4</em> in human ovaries it is concluded that the granulosa cells do not interact with the theca for the synthesis of E as the follicle enlarges from 1 to 10 mm in diameter. Indeed, excessive thecal delta <em>4</em> during this growth phase probably inhibits normal follicular development. However, as the follicle enlarges beyond 10 mm in diameter, and as the granulosa cells begin to preferentially metabolize delta <em>4</em> to E, the two cell-types of the follicle may increasingly interact to enhance the follicular output of E.
Publication
Journal: Journal of steroid biochemistry
December/17/1979
Authors
Publication
Journal: Journal of Steroid Biochemistry and Molecular Biology
October/30/2003
Abstract
Estrogens play a crucial role in multiple functions of the brain and the proper balance of inactive estrone and active estradiol-17beta might be very important for their cerebral effects. The interconversion of estrone and estradiol-17beta in target tissues is known to be catalysed by a number of human 17beta-hydroxysteroid dehydrogenase (17beta-HSD) isoforms. The present study shows that enzyme catalysed interconversion of estrone and estradiol-17beta occurs in the human temporal lobe. The oxidative cerebral pathway preferred estradiol-17beta to Delta(5)-androstenediol and testosterone, whereas the reductive pathway preferred dehydroepiandrosterone (DHEA) to Delta(<em>4</em>)-<em>androstenedione</em> and estrone. An allosteric Hill kinetic for NAD-dependent oxidation of estradiol-17beta was observed, whereas a typical Michaelis-Menten kinetic was shown for NADPH-dependent reduction of estrone. Investigations of the interconversion of estrogens in cerebral neocortex (CX) and subcortical white matter (SC) preparations of brain tissue from 12 women and 10 men revealed no sex-differences, but provide striking evidence for the presence of at least one oxidative membrane-associated 17beta-HSD and one cytosolic enzyme that catalyses both the reductive and the oxidative pathway. Membrane-associated oxidation of estradiol-17beta was shown to be significantly higher in CX than in SC (P<0.05), whereas the cytosolic enzyme activities were significantly higher in SC than in CX (P<0.0005). Finally, real-time RT-PCR analyses revealed that besides 17beta-HSD types <em>4</em> and 5 also the isozymes type 7, 8, 10 and 11 show substantial expression in the human temporal lobe. The characteristics of the isozymes lead us to the conclusion that cytosolic 17beta-HSD type 5 is the best candidate for the observed cytosolic enzyme activities, whereas the data gave no clear answer to the question, which enzyme is responsible for the membrane-associated oxidation of estradiol-17beta. In conclusion, the study strongly suggests that different cell types and different isozymes are involved in the cerebral interconversion of estrogens, which might play a pivotal role in maintaining the functions of the central nervous system.
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