[The role of ACTH in regulating dehydroepiandrosterone secretion in primates]

The effect of repeated administration of a prolonged ACTH agent on the secretion of glucocorticoids, dehydroepiandrosterone (DEA) and delta 4- and delta 5-precursors was studied in experiments on male hamadryas baboons. The administration of Sinacten-depot at a dose of 1 mg for 5 days caused a noticeable decrease in the basal levels of cortisol, 11-deoxycortisol, pregnenolone, 17-oxypregnenolone, and DEA. Response of the adrenal glands to additional ACTH stimulation against a background of lowered basal indicators was completely preserved and increased 2-3-fold for pregnenolone, 17-oxypregnenolone and DEA. The amplitude of a maximum increment of cortisol in response to stress before and after ACTH treatment did not differ significantly, and for DEA it increased three times. Immobilization stress after preliminary ACTH treatment caused a stable increase in the level of DEA during stress factor action as well as 3 days after drug action.

Delta 5-3 beta-hydroxysteroid dehydrogenase-isomerase activity in canine pancreas

Activity of delta 5-3 beta-hydroxysteroid dehydrogenase coupled with steroid-delta 5-4-isomerase was demonstrated for the first time in the pancreas. The enzyme complex was assayed by measuring the conversion of pregnenolone to progesterone as well as of dehydroepiandrosterone to androstenedione and found to be localized primarily in the mitochondrial fraction of dog pancreas homogenates. The delta 5-3 beta-hydroxysteroid dehydrogenase used either NAD+ or NADP+ as co-substrates, although maximal activity was observed with NAD+. In phosphate buffer, pH 7.0 and 37 degrees C, the apparent Km values of the dehydrogenase were 6.54 +/- 0.7 microM for pregnenolone and 9.61 +/- 0.8 microM for NAD+. The apparent Vmax was determined as 0.82 +/- 0.02 nmol min-1 mg-1. Under the same conditions the Km values for dehydroepiandrosterone and NAD+ were 3.3 +/- 0.2 microM and 9.63 +/- 1.6 microM, respectively, and the apparent Vmax was 0.62 +/- 0.01 nmol min-1 mg-1.

Inhibition of aflatoxin B1 binding to hepatic DNA by dehydroepiandrosterone in vivo

Dehydroepiandrosterone (DHEA) a naturally occurring steroid, has been reported to inhibit the binding of N-dimethylnitrosamine and 7,12-dimethylbenz[a]anthracene to DNA in vivo and to increase glutathione transferase activity. In this study, we have investigated if DHEA could protect hepatic DNA from damage by the potent hepatocarcinogen aflatoxin B1 (AFB1). Young male Fischer 344 (2-month-old) rats were fed a diet containing 0.8% DHEA for 14 days. Control rats were pair-fed the same diet without DHEA. The rats were then administered a single i.p. dose of [3H]AFB1 in dimethylsulfoxide (0.6 mg/kg body weight; 200 mCi/mmol) and killed after 3 h. Liver weight, mitochondrial, microsomal and cytosolic protein, cytochrome P450 content and glutathione transferase activity increased significantly (P less than 0.001) in DHEA-fed rats; however, the hepatic DNA content was not altered. DHEA feeding increased the total amount of AFB1 bound to hepatic protein but decreased the extent of DNA binding. In in vitro experiments, there was less total binding to DNA and protein by AFB1 when using microsomes from DHEA-fed rats. These results suggest that DHEA inhibits the binding of AFB1 to DNA by modifying the biotransformation of the carcinogen.

The testes of moles (Talpa europaea) retain a considerable microsomal capacity for androgen synthesis during seasonal regression

Seasonal changes in testicular histology and steroidogenesis were investigated in the mole (Talpa europaea). Androgen synthesis was examined by incubating [4-14C]pregnenolone (P) and [4-14C]dehydroepiandrosterone (DHA) with testicular minces in a static incubation system. The metabolites formed were characterized by thin-layer chromatography. Morphological changes were studied by routine histological methods. During sexual quiescence spermatogenesis was arrested. The regressive seminiferous tubules consisted predominantly of Sertoli cells and spermatogonia. On the other hand, histological quantification suggested that season has no significant effects on the number or the nuclear dimensions of Leydig cells in this species. The capacity of the regressive testes (per unit weight) to metabolize P and DHA to testosterone (T) was somewhat greater in regressive (48.5%, 49.4%) than in active (33.2%, 41.6%) testes. The results also suggest that the greater in vitro T production encountered during reproductive quiescence is due possibly to an increase in the activity of 17 beta-hydroxysteroid dehydrogenase (per unit weight). Our data on Leydig cell numbers indicate, however, that the capacity of the individual Leydig cells to produce T is decreased during sexual regression. T. europaea appears to be quite exceptional among seasonally breeding small mammals exhibiting pronounced annual changes in spermatogenesis in that the testes retain a considerable enzymatic capacity to produce testosterone from pregnanes during sexual quiescence. The results suggest that pituitary as well as paracrine regulation of the annual testicular cycle in this species differs from that generally encountered in seasonal breeders.

Precursors of plasma androstanediol- and androgen-glucuronides in women

Although androstanediol (AD) and androstanediolglucuronide (ADG) are generally considered to be parameters of peripheral androgen action, their plasma levels do not always vary in parallel, suggesting that they may have different precursors. Few hard data being available concerning ADG precursors in women, we studied in postmenopausal women with absent or suppressed adrenal function, the blood conversion rates of testosterone (T), dihydrotestosterone (DHT), androstenedione (A) and dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) to AD and ADG respectively, as well as the conversion of AD to ADG. Moreover conversions of these precursors to testosteroneglucuronide (TG) and dihydrotestosteroneglucuronide (DHTG), respectively, were also studied. Our data show that, whereas plasma A and DHT are the major precursors of AD, plasma DHEAS and A are the major precursors of plasma ADG, accounting for 50 and 15%, respectively, of plasma ADG, A being the major precursor of plasma TG and DHTG, respectively. When the conversion rates, obtained in this study, were applied to the plasma concentration of precursors found in normal young and postmenopausal women, respectively, the calculated concentration of product steroids accounted for almost the totality of the actual plasma levels of ADG, TG and DHTG respectively. The difference in relative importance of their precursors, explains that plasma concentrations of AD and ADG do not always vary in parallel; moreover, the importance of DHEAS as precursor of ADG explains the suppression by dexamethasone and the increase after adrenocortical stimulation of plasma ADG levels.

Effect of placental factors on growth and function of the human fetal adrenal in vitro

Conditioned medium from human placental monolayer cultures (PM) had a marked stimulatory effect on proliferation (3H-thymidine uptake) of human fetal zone adrenal cells in primary monolayer culture, even in the absence of serum. Epidermal growth factor (EGF) and fibroblast growth factor (FGF) also significantly stimulated fetal adrenal cell growth. However, the effects of PM differed from those of EGF and FGF in several respects: 1) maximal response to PM was 2-5 times greater; 2) mitogenic effects of EGF and FGF were suppressed by adrenocorticotropic hormone (ACTH), whereas that of 50% PM was not; 3) PM inhibited ACTH-stimulated steroidogenesis (dehydroepiandrosterone sulfate and cortisol), but EGF and FGF did not. Preliminary characterization studies have indicated that approximately half of the placental growth-promoting activity is heat resistant and sensitive to bacterial proteases, and that 50-60% of the activity is lost after dialysis with membranes having a molecular weight cutoff of 3500. These findings suggest a role for the placenta in the growth and differentiated function of the human fetal adrenal gland.

Suppression of serum dehydroepiandrosterone sulfate levels by insulin: an evaluation of possible mechanisms

We previously demonstrated a progressive decline in serum dehydroepiandrosterone sulfate (DHEA-S) levels in women during a hyperinsulinemic-euglycemic clamp. To determine whether this fall in serum DHEA-S levels might have been due to insulin-stimulated 1) hydrolysis of DHEA-S to dehydroepiandrosterone (DHEA), 2) conversion of DHEA-S/DHEA to androstenedione, and/or 3) urinary excretion of these steroids, 10 additional men were studied by the hyperinsulinemic-euglycemic clamp technique. Each man received a 0.1 U/kg (0.72 nmol/kg) insulin bolus dose, followed by a 10 mU/kg.min (72 pmol/kg.min) insulin infusion for 4 h. An average insulin level of 12,390 +/- 259 (+/- SE) pmol/L (1,726.8 +/- 36 microU/mL) was achieved; serum glucose was maintained at 5.0 +/- 0.1 mmol/L (90.5 +/- 2.3 mg/dL). During the hyperinsulinemia, serum DHEA-S levels fell progressively and were significantly lower than baseline at 4 and 6 h of study (85.5 +/- 5.9% and 79.1 +/- 3.2% of baseline values, respectively; P less than 0.05). Serum DHEA levels fell concurrently and were significantly lower than baseline at 2, 4, and 6 h of study (66.2 +/- 12.3%, 61.6 +/- 11.2%, and 52.9 +/- 10.2% of baseline values, respectively; P less than 0.05). The percent fall in serum DHEA levels correlated positively with the percent fall in serum DHEA-S levels (r = 0.44; P less than 0.02). Serum androstenedione levels also fell progressively during hyperinsulinemia and were significantly lower than baseline at 2, 4, and 6 h of study (71.5 +/- 4.1%, 71.0 +/- 7.2%, and 48.1 +/- 3.3% of baseline values, respectively; P less than 0.05). No change in serum DHEA-S, DHEA, or androstenedione levels occurred in paired control studies, during which 0.45% saline was infused at rates matched exactly to the rates of the dextrose and insulin infusions during the hyperinsulinemic clamp studies. Despite decreasing serum DHEA-S and DHEA levels during hyperinsulinemia, urinary DHEA-S and DHEA glucuronide excretions were increased by 50% (P less than 0.05) and 86% (P = 0.05), respectively, compared to urinary excretion of these steroids during control studies. In contrast, urinary excretion of unconjugated DHEA was unchanged. Quantitatively, however, increased urinary excretion of conjugated DHEA during hyperinsulinemia accounted for only about 5% of the concomitant fall in serum DHEA-S concentrations.(ABSTRACT TRUNCATED AT 400 WORDS)

Development and fertility of ovaries in the B6.YDOM sex-reversed female mouse

When the Y chromosome of Mus musculus domesticus (YDOM) was introduced onto the C57BL/6 (B6) mouse background, half of the XY progeny (B6.YDOM) developed bilateral ovaries and female internal and external genitalia. We examined the fertility of the B6.YDOM sex-reversed female mouse. The chromosomal sex of the individual mouse was identified by dot hybridization with mouse Y chromosome-specific DNA probes. The results indicated that all XY females lacked regular estrous cyclicity although most were able to mate and ovulate after treatment with gonadotropins. When they had been ovariectomized and grafted with ovaries from the XX female litter mate, they initiated estrous cyclicity. Reciprocally, the XX female that had received XY ovarian grafts did not resume estrous cyclicity. Development of the XY ovary was morphologically comparable to the XX ovary until 16 day of gestation (d.g.), when most germ cells had reached the zygotene or pachytene stage of meiotic prophase. However, by the day of delivery (19 or 20 d.g.), no oocyte remained in the medullary cords of the XY ovary. In the control XX ovary, the first generation of follicles developed in the medullary region, and 5 delta-3 beta-hydroxysteroid dehydrogenase (3 beta-HSDH) activity appeared first in the stromal cells around growing follicles by 10 days after birth. In contrast, in the XY ovary, follicles were not formed in the medullary region, and 3 beta-HSDH activity appeared in epithelial cells of the oocyte-free medullary cords. Primordial follicles in the cortex region continued development in both the XX and XY ovaries. These results suggest that the XY female is infertile due to a defect inside the XY ovary. The prenatal loss of oocytes in the medullary cords may be a key event leading to abnormal endocrine function, and thereby, the absence of estrous cyclicity.

Effect of estrogen on pituitary peptide-induced dehydroepiandrosterone secretion in the baboon fetus at midgestation

We have previously shown that ACTH and PRL stimulate baboon fetal adrenal dehydroepiandrosterone (DHA) production both in vitro and in vivo and that estrogen diminishes the responsivity of the adrenal to tropic peptides in vitro. In the present study we determined the effects of increasing placental estrogen production by the administration of androstenedione at midgestation on DHA production by the baboon fetus in vivo. Pregnant baboons were untreated (n = 8) or treated (n = 9) with increasing numbers of androstenedione implants inserted in the mother at 8-day intervals between days 70-100 of gestation (term = day 184). On day 100, the fetuses were exteriorized, and a constant infusion of saline (0.1 ml/min) was initiated via a catheter inserted into a femoral vein of the fetus. At 40 min, a bolus injection of either 30 nmol ACTH or 40 nmol ovine PRL was administered to fetuses. ACTH or PRL (0.2 nmol/min.0.1 ml saline) were then infused for an additional 25 min. The concentrations of serum estradiol (E2) in the uterine vein (20.2 +/- 1.5 ng/ml; mean +/- SE) and estrone (E1) in umbilical vein (11.9 +/- 3.1 ng/ml) of androstenedione-treated baboons were 2-fold greater (P less than 0.05) than respective values in untreated baboons. Baseline concentrations of DHA in the femoral vein of the fetus were similar in all treatment groups (overall mean, 120 +/- 20 ng/ml) and greater (P less than 0.05) than values (27 +/- 3) in the mother. In untreated control baboons, basal DHA concentrations in the fetus were increased (P less than 0.05) by 69 +/- 17% and 94 +/- 29% after fetal injection of ACTH (n = 4) or PRL (n = 4), respectively. In contrast, neither PRL (n = 5) nor ACTH (n = 4) had any effect on serum DHA when injected into androstenedione-treated baboons. Regardless of treatment, injection of ACTH or PRL into the fetus had no effect on DHA concentrations in the mother. Collectively, these findings indicate that the ability of the fetal adrenal to increase DHA production in response to an acute infusion of ACTH or PRL was abolished in baboons in which placental estrogen production was increased prematurely at midgestation. Therefore, we suggest that during the second half of gestation in the baboon a regulatory system may exist in utero, in which there is feedback control of the placental product estrogen on the formation of the fetal adrenal precursor DHA.

Prolactin secretion and dehydroepiandrosterone sulphate plasma levels in women with benign breast disease

The purpose of the present investigation was to verify possible positive correlations between prolactin secretion and dehydroepiandrosterone sulphate levels in plasma of women with benign breast disease. Prolactin secretion was evaluated in terms of basal levels, maximum peak, percent increase above baseline levels, total integrated area, response area after TRH stimulation. No correlation was found between the parameters of prolactin secretion and dehydroepiandrosterone sulphate levels.

Steroid secretion by a virilizing lipoid cell ovarian tumor: origins of dehydroepiandrosterone sulfate

A 78-year-old woman had a 3-year history of severe virilization caused by a lipoid cell ovarian tumor localized by pelvic ultrasound examination and NP-59 scan. Steroid secretion was evaluated by the following: 1) peripheral plasma levels before and after hormonal stimulation with ACTH or hCG, 2) venous catheterization and measurement of steroid levels in the left and right ovarian veins during surgery, 3) measurements of enzymatic activities in the tumor tissue compared with those in normal ovarian tissue, and 4) steroid secretion studies in vitro of the tumor tissue, surrounding tissue, and contralateral ovarian tissue. The tumor tissue secreted both delta 5 and delta 4 androgens, including dehydroepiandrosterone sulfate. Dehydroepiandrosterone sulfate was also secreted by the surrounding and contralateral ovarian tissue.

The concentration of 16x-hydroxy androgens in serum and cyst fluid of women with gross cystic disease of the breast

The concentrations of 16 alpha-hydroxydehydroepi-androsterone sulfate (16 alpha-OHDHAS) and androst-5-ene-3 beta, 16 alpha-, 17 beta-triol-3-sulfate (A-TriolS) were measured in the plasma and breast cyst fluid (BCF) of women with gross cystic disease of the breast. In the 19 BCF samples analyzed, the 16 alpha-OHDHAS and A-TriolS concentrations ranged from 15 to 1130 ng/mL, and 12 to 871 ng/mL, respectively. However the concentrations of these steroids in the sera of these women were lower (15-179 ng/mL, 8-80 ng/mL, respectively). Estriol-3-sulfate (E3-3S) concentrations in the BCF samples ranged from barely detectable (0.2 ng/mL) to 3 micrograms/mL. In BCF or serum a positive linear correlation was observed in the concentration of 16 alpha-OHDHAS and A-TriolS (p less than 0.001 and 0.05, respectively). However, in the same patients no statistical significance was observed in the BCF vs serum concentrations of these two steroids. When the specimens from this and previous studies were combined, positive correlation was found between potassium ion concentration and E3-3S or 16 alpha-OHDHAS. The origin of the high concentration of E3-3S is still obscure. Although no linear correlation between 16 alpha-OHDHAS and E3-3S was observed, the possibility of a precursor-product relationship between the two is not elimnated.

[Changes in 13,14-dihydro-15-keto-prostaglandin F2 alpha and dehydroepiandrosterone-sulfate (DHA-S) levels in amniotic fluid and maternal peripheral venous blood in late pregnancy and during labor]

To study the role of prostaglandin (PG) and steroids on the mechanism of parturition, levels of 13,14-dihydro-15-keto-prostaglandin F2 alpha (dhk.PGF2 alpha) and dehydroepiandrosterone-sulfate (DHA-S) in amniotic fluid and plasma during late pregnancy, labor, and puerperium, were measured by radioimmunoassay and gas chromatography-mass spectrometry. Seven patients at term were selected for this study and labor was induced by amniotomy. Amniotic fluid and maternal peripheral blood were obtained simultaneously from each individual at A) the artificial rupture of the membranes before the onset of labor, B) the onset of labor, C) the second stage of labor, D) the delivery, and E) 2 hours postpartum. No increase in either amniotic fluid or plasma dhk-PGF2 alpha was noticed when compared before and at the onset labor. However, there was a steady increase during labor and the maximum was reached at delivery. The dhk-PGF2 alpha concentration in amniotic fluid correlated well with that in maternal plasma. A similar pattern was observed in the DHA-S levels both in amniotic fluid and plasma. No apparent change was observed before the onset of labor, but there was a tendency to increase during labor. A significant correlation between the levels of dhk.PGF2 alpha and DHA-S in amniotic fluid was noticed. From the results obtained above, it is suggested that PG and DHA-S may be involved not in the initiation of labor but in the promotion of parturition. The biological significance of DHA-S on PG levels remains to be clarified.

Extensive esterification of adrenal C19-delta 5-sex steroids to long-chain fatty acids in the ZR-75-1 human breast cancer cell line

Estrogen-sensitive human breast cancer cells (ZR-75-1) were incubated with the 3H-labeled adrenal C19-delta 5-steroids dehydroepiandrosterone (DHEA) and its fully estrogenic derivative, androst-5-ene-3 beta,17 beta-diol (delta 5-diol) for various time intervals. When fractionated by solvent partition, Sephadex LH-20 column chromatography and silica gel TLC, the labeled cell components were largely present (40-75%) in three highly nonpolar, lipoidal fractions. Mild alkaline hydrolysis of these lipoidal derivatives yielded either free 3H-labeled DHEA or delta 5-diol. The three lipoidal fractions cochromatographed with the synthetic DHEA 3 beta-esters, delta 5-diol 3 beta (or 17 beta)-monoesters and delta 5-diol 3 beta,17 beta-diesters of long-chain fatty acids. DHEA and delta 5-diol were mainly esterified to saturated and mono-unsaturated fatty acids. For delta 5-diol, the preferred site of esterification of the fatty acids is the 3 beta-position while some esterification also takes place at the 17 beta-position. Time course studies show that ZR-75-1 cells accumulate delta 5-diol mostly (greater than 95%) as fatty acid mono- and diesters while DHEA is converted to delta 5-diol essentially as the esterified form. Furthermore, while free C19-delta 5-steroids rapidly diffuse out of the cells after removal of the precursor [3H]delta 5-diol, the fatty acid ester derivatives are progressively hydrolyzed, and DHEA and delta 5-diol thus formed are then sulfurylated prior to their release into the culture medium. The latter process however is rate-limited, since new steady-state levels of free steroids and fatty acid esters are rapidly reached and maintained for extended periods of time after removal of precursor, thus maintaining minimal concentrations of intracellular steroids. The rapid rate and large extent of esterification of DHEA and delta 5-diol to long-chain fatty acids in breast cancer cells indicate that this reaction could constitute an important regulatory step in the estrogenic action of DHEA and delta 5-diol in these cells.

Recovery of hormone secretion after chronic gonadotropin-releasing hormone agonist administration in women with polycystic ovarian disease

Persistent suppression of gonadotropin and ovarian steroid production can be achieved in women with polycystic ovarian disease (PCO) by daily administration of a long-acting GnRH agonist (GnRHa). This study was designed to determine the patterns of recovery of clinical responses and hormonal secretion after chronic GnRHa administration in women with PCO. Six women with PCO were treated with daily sc injections of [D-His6(imBzl),Pro9-NEt]GnRHa (100 micrograms) for 6 months. Blood samples were obtained at the time of and three times weakly for 90 days after discontinuation of agonist therapy. In five women who did not ovulate, the suppressed serum FSH levels rose to pretreatment values within 10 days. In contrast, a gradual and progressive increase in serum LH (as measured by bioassay and immunoassay) was apparent by day 18. The LH increase coincided with progressive increases in serum estrone (E1), androstenedione, and testosterone. Serum estradiol (E2) began to rise on day 28. All hormones returned to their pretreatment baseline values within the 90-day recovery interval, with the exception of E2. Trend analysis of the slopes of recovery revealed that the incremental secretion patterns of E1, E2, androstenedione, and testosterone differed significantly from that of FSH, but not from those of bioactive or immunoactive LH. Serum progesterone, dehydroepiandrosterone sulfate, and cortisol did not change after withdrawal of GnRHa. One woman ovulated spontaneously on day 52 before which her hormone secretion patterns were indistinguishable from those of the other women. In summary, 1) during recovery after discontinuation of chronic GnRH agonist therapy the patterns of FSH and LH release suggested resumption of endogenous GnRH action on the pituitary with greater release of FSH than LH, a pattern that would be expected in the absence of ovarian steroid influence; 2) the lack of early estrogen production despite the increase in serum FSH concentrations suggests inadequate FSH secretion, abnormal ovarian responsiveness to FSH, or impaired FSH bioactivity; 3) androgen secretion was provoked by the increase in LH secretion; 4) per unit LH measured by bioassay, greater ovarian androgen secretion was stimulated in PCO than ovulatory women; and 5) the likelihood of spontaneous ovulation during recovery was minimal.

Effect of tamoxifen on the activity of enzymes of testicular steroidogenesis

Testicular homogenates of tamoxifen-treated rats were incubated with labeled steroid precursors (progesterone, 17 alpha-hydroxyprogesterone, dehydroepiandrosterone, androstenedione or testosterone) in order to study the effect of tamoxifen on testicular steroidogenesis. The results indicate that a 9 day treatment with a daily dose of 1 mg tamoxifen produces a reduction of the synthesis of testosterone. Inhibition of the 17 alpha-hydroxylase and C17,20-desmolase enzyme systems was observed together with an increased 20 alpha-hydroxysteroid dehydrogenase activity.

Lack of effect of insulin or insulin-like growth factor I on the steroid sulfatase activity of human placental cytotrophoblasts

Hyperinsulinemia is known to reduce serum dehydroepiandrosterone sulfate (DHEA-S) levels in normal females. A possible mechanism for this phenomenon would be an insulin-mediated increase in steroid sulfatase activity, with insulin acting either via activation of the insulin receptor or via cross-reaction with the insulin-like growth factor I (IGF-I) receptor. Using a well characterized human cytotrophoblast system, the presence of steroid sulfatase activity in isolated cytotrophoblasts was documented. Half maximal cellular hydrolysis of DHEA-S was observed at a substrate concentration of 9.6-14.5 microM, and maximal hydrolysis at a concentration of 75-100 microM. The hypothesis that insulin increases steroid sulfatase activity was examined by exposing cytotrophoblasts to supraphysiological concentrations of either insulin (2 micrograms/ml) or IGF-I (20 ng/ml) for 24 h and then measuring the rate of DHEA-S hydrolysis. Insulin failed to affect cytotrophoblastic steroid sulfatase activity, irrespective of whether the substrate concentration was 20 microM or 100 microM. IGF-I also exerted no effect on steroid sulfatase activity. These data indicate that neither insulin nor IGF-I affect the steroid sulfatase activity of human cytotrophoblasts. An effect of insulin or IGF-I on the steroid-sulfatase activity of other tissues has not been excluded. These observations suggest that the decline in serum DHEA-S levels during hyperinsulinemia is not mediated via an insulin-induced increase in steroid sulfatase activity.

Aromatase inhibition in hypophysectomised female rats: a novel animal model for in vivo screening

An experimental model for in vivo screening of aromatase inhibitors was developed which overcomes the interference of compounds centrally active via the pituitary-gonad axis. Mature female surgically or chemically hypophysectomised (hypx) rats were treated with the oestrogen precursor dehydroepiandrosterone sulphate (DHEAS), immediately followed by administration of the test compound. During the treatment period vaginal smears were prepared daily. In the hypx rats DHEAS was metabolised to oestrogens, which induced vaginal cornification. By determining oestradiol levels it was shown that the aromatase inhibitors tested antagonised oestrogen synthesis and, as a result, cornification was counteracted. 4-Hydroxyandrostenedione and SH 489 showed equipotent aromatase inhibition, whereas 19-mercapto-androstenedione (ORG 30365) was at least twice as potent as the former compounds. By using various oestrogen precursors the inhibition of the enzyme aromatase was demonstrated. For in vivo screening of compounds on their aromatase inhibiting activity the assay in hypx rats appeared to be very suitable and selective but, because anti-oestrogens also antagonise vaginal cornification, anti-oestrogenic activity has to be excluded.

Partial characterization of steroid sulfohydrolase and steroid sulfotransferase activities in purified porcine Leydig cells

Subcellular fractions of purified pig Leydig cells from 7 different animals have been investigated with respect to their abilities to catalyze the sulfation of several steroids and the hydrolysis of the sulfated forms of these same steroids. Considerable estrone sulfate sulfohydrolase of pH optimum 7.5 and high apparent Km was found to be concentrated in the 105,000 g pellet but no evidence was obtained, in any subcellular fraction, for the presence of any activity toward the 3-sulfate of pregnenolone, dehydroepiandrosterone (DHA) or delta 5-androstene-3 beta,17 beta-diol (androstenediol). Cytosolic sulfotransferase activity toward estrone, pregnenolone, DHA and androstenediol was present in each animal. The activity toward these 4 substrates was eluted from a gel filtration column as a single peak of apparent molecular weight 43 KDa. Upon chromatofocusing, a sharp estrogen sulfotransferase peak of apparent pI 6.1 and pH optimum 9.5, was clearly separated from the neutral steroid sulfotransferase which eluted over a more acidic pH range in a manner suggestive of the presence of several isozymes. This latter, which exhibited a wide pH optimum range between 6 and 8.5, was most active toward androstenediol, and least active toward pregnenolone. The estrogen sulfotransferase exhibited Michaelis-Menten kinetics (apparent Km = 4 microM). The neutral steroid sulfotransferase activity increased in velocity with increasing androstenediol or DHA concentration up to 1 microM beyond which considerable substrate inhibition occurred. It appears from these data that neutral steroid sulfates synthesized in the pig Leydig cell are not subject to enzymic desulfation in the same cells.

Specificity of the dexamethasone-induced steroid receptor in Tetrahymena

The dexamethasone-induced steroid receptor of Tetrahymena pyriformis specifically binds triamcinolone, which is itself a fluorinated glucocorticoid. It also binds dihydro-epi-androsterone (DHEA) but no or very little testosterone, digoxin or ouabain. It follows that the specificity of the induced steroid receptor of Tetrahymena may only partially be comparable with that of the mammalian steroid receptor.

Hormone status in patients with slipped capital femoral epiphysis

In 15 consecutive patients with slipped capital femoral epiphysis we recorded height, weight and skeletal maturity. Sexual maturity was assessed clinically and biochemically, and Harris's hypothesis that there is an increased ratio of serum growth hormone to oestrogen was tested in comparison with 15 age and sex matched controls. We found no difference in skeletal or sexual maturity between the groups, or any overt endocrine abnormality in the patients. However almost half the patients with slipped epiphysis were over the 90th weight percentile, suggesting that mechanical factors such as obesity are more important aetiologically than endocrine abnormalities.

Biosynthetic pathways of testosterone and estradiol-17 beta in slices of the embryonic ovary and testis of the chicken (Gallus domesticus)

To elucidate synthetic pathways of testosterone and estradiol-17 beta in embryonic gonads of the chicken, metabolism of various 14C-labeled steroids in slices of the left ovaries and paired testes of 15- and 9-day-old chicken embryos was examined. (1) Fifteen-day-old chicken embryos: From pregnenolone, more 17 alpha-hydroxypregnenolone was produced than progesterone in the ovary, while more progesterone was produced than 17 alpha-hydroxypregnenolone in the testis. From 17 alpha-hydroxypregnenolone, however, only dehydroepiandrosterone was detected as a product in both gonads. Dehydroepiandrosterone was converted mainly into androstenedione and its 5 beta-reduced derivatives by both gonads. Progesterone was converted into 5 beta-pregnane-3,20-dione more than into 17 alpha-hydroxyprogesterone by both gonads. Both gonads metabolized 17 alpha-hydroxyprogesterone, androstenedione, and testosterone predominantly into their corresponding 5 beta-reduced steroids, while production of androstenedione from 17 alpha-hydroxyprogesterone and of testosterone from androstenedione was limited. Estradiol-17 beta was produced from androstenedione and testosterone only by the ovary. (2) Nine-day-old chicken embryos: From pregnenolone, production of progesterone and 17 alpha-hydroxypregnenolone was similar in the ovary. On the other hand, in the testis, more progesterone was produced than 17 alpha-hydroxypregnenolone from pregnenolone. For delta 4-3-oxo steroids, strong activity of 5 beta-reductase was demonstrated in both gonads. From these results, both delta 4- and delta 5-pathways are involved in the formation of testosterone and then finally of estradiol-17 beta by the embryonic gonads of the chicken, and relative preference for the pathway seems to depend on sexes and embryonic ages. In addition, it is suggested that steroidogenesis in these embryonic gonads is characterized by marked activity of 5 beta-reductase, irrespective of sexes or ages.

Porcine brain natriuretic peptide receptor in bovine adrenal cortex

The action of porcine brain natriuretic peptide (pBNP) on the steroidogenesis was investigated in cultured bovine adrenocortical cells. Porcine BNP induced a significant dose-dependent inhibition of both ACTH- and A II-stimulated aldosterone secretion. 10(-8) M and 10(-7) M pBNP also significantly inhibited ACTH-stimulated cortisol and dehydroepiandrosterone (DHEA) secretions. Binding studies of [125I]-pBNP to bovine adrenocortical membrane fractions showed that adrenal cortex had high-affinity and low-capacity pBNP binding sites, with a dissociation constant (Kd) of 1.70 x 10(-10) M and a maximal binding capacity (Bmax) of 19.9 fmol/mg protein. Finally, the 135 Kd radioactive band was specially visualized in the affinity labeling of bovine adrenal cortex with disuccinimidyl suberate (DSS). These results suggest that pBNP may have receptor-mediated suppressive actions on bovine adrenal steroidogenesis, similar to that in atrial natriuretic peptide (ANP).