Metabolism of 5 alpha-androstane-3 beta,17 beta-diol to 17 beta-hydroxy-5 alpha-androstan-3-one and 5 alpha-androstan-3 alpha,17 beta-diol in the rat

Establishment and characterization of an immortalized but non-transformed human prostate epithelial cell line: BPH-1

This report describes the development and characterization of an epithelial cell line (BPH-1) from human prostate tissue obtained by transurethral resection. Primary epithelial cell cultures were immortalized with SV40 large T antigen. One of the isolated clones was designated BPH-1. These cells have a cobblestone appearance in monolayer culture and are non-tumorigenic in nude mice following subcutaneous injection or subrenal capsule grafting. They express the SV40 large T antigen and exhibit increased levels of p53, as determined by immunocytochemistry. Cytogenetic analysis by G-banding demonstrated an aneuploid karyotype with a modal chromosome number of 76 (range 71 to 79, n = 28) and 6 to 8 marker chromosomes. Some structurally rearranged chromosomes were observed, but the Y chromosome was normal. The expressed cytokeratin profile was consistent with a prostatic luminal epithelial cell. This profile was the same as that of primary prostatic epithelial cultures from which the BPH-1 cells were derived. In serum-free culture in plastic dishes epidermal growth factor (EGF), transforming growth factor (TGF)-alpha, fibroblast growth factor (FGF) 1 (aFGF), and FGF 7 (KGF) induced increased proliferation in these cells whereas FGF 2 (bFGF), TGF-beta 1, and TGF-beta 2 inhibited proliferative activity. Testosterone had no direct effect on the proliferative rate of BPH-1 cells. 5 alpha-Reductase, 3 alpha-hydroxysteroid oxidoreductase, and 17 beta-hydroxy-steroid oxidoreductase activities were detected in BPH-1 cells. Expression of androgen receptors and the secretory markers, prostate specific antigen and prostatic acid phosphatase, were not detectable by immunocytochemistry, biochemical assay, or RT-PCR analysis.

Androgen metabolism in the different lobes of the prostate gland of intact, gonadectomized or hypophysectomized rats with or without androgen substitution

The effect of gonadectomy or hypophysectomy and the effect of substitution with testosterone, upon the reductive and oxidative metabolic transformations of testosterone, 4-androstene-3,17-dione, 17 beta-hydroxy-5 alpha-androstane-3-one, 5 alpha-androstane-3 alpha, 17 beta-diol and 5 alpha-androstane-3 beta, 17 beta-diol using NAD(H) and NADP(H) as added cofactors were examined in homogenates from the ventral (VP), lateral (LP) and dorsal prostate (DP), and coagulating gland (CG) of adult Wistar rats. The fall in serum testosterone induced by gonadectomy or hypophysectomy led to reduced activity of 5 alpha-reductase, NADP(H)-dependent 3 alpha-hydroxysteroid oxidoreductase (3 alpha-HSOR), NAD-dependent 3 alpha-HSOR, 3 beta-HSOR and 17 beta-HSOR, indicating that these enzymes are androgen dependent. The NADP dependent oxidation of 5 alpha-androstane-3 alpha, 17 beta-diol in LP increased upon hypophysectomy and gonadectomy. Testosterone substitution of gonadectomized or hypophysectomized rats generally maintained enzymatic activity at the level of the control group, except for the 5 alpha-reductase activity which fell in spite of this treatment. Hypophysectomy or gonadectomy had different effects on the activity of several androgen metabolizing enzymes; 5 alpha-reductase activity in DP and CG, NAD(H) dependent 3 alpha-HSOR in VP and NADPH dependent 3 beta-HSOR activity in LP, DP and CG. There were marked differences between the rat prostatic lobes, both concerning the activity of the androgen metabolizing enzymes and the responses to the different treatment modalities.

Effects of chronic ethanol intake on aromatization of androgens and concentration of estrogen and androgen receptors in rat liver

The present study was carried out to investigate if ethanol alters aromatization of androgens and concentrations of hepatic estrogen and androgen receptors. Hepatic aromatization of androgen to estrogen was significantly increased by ethanol administration. There was a significant increase in serum estrogen level but a decreased circulating testosterone level in alcohol-fed rats. Furthermore, the concentration of estrogen receptors in liver cytosol was significantly higher in alcohol-fed rats (37 +/- 5.3 fmol/mg protein), as compared to the intact control value (21 +/- 4.8 fmol/mg protein). However, hepatic androgen receptor levels were much lower (4.4 +/- 0.5) in alcohol-fed rats than those (10.2 +/- 1.4 fmol/mg protein) in control animals. Similarly, castration increased hepatic aromatization of androgens and concentrations of serum estrogen and hepatic estrogen receptors, but it decreased contents of circulating androgen and hepatic androgen receptors. These findings indicate that alcohol administration is considered a chemical form of castration, altering the hepatic steroid metabolism and sex hormone receptor contents and contributing to the pathogenesis of feminization. A combination of alcohol-feeding and castration has no synergistic effect on the hepatic steroid receptors and aromatization, but this combination does have a more profound effect in lowering the concentration of circulating androgen.

Ethanol directly increases dihydrotestosterone conversion primarily to 5 alpha-androstan-3 beta, 17 beta-diol in rat Leydig cells

Our studies demonstrate that direct stimulation of dihydrotestosterone metabolism by ethanol (2.2 - 65 mM) in rat Leydig cells primarily involves an increase in 5 alpha-androstan-3 beta, 17 beta-diol. Although the enzyme catalyzing this conversion, 5 alpha-androstane-3 beta-hydroxysteroid dehydrogenase, is localized in the microsomal fraction of Leydig cells, ethanol does not increase 5 alpha-androstan-3 beta, 17 beta-diol formation in isolated microsomes, presumably because of the removal of soluble alcohol dehydrogenase activity, which we propose mediates this action. Because 5 alpha-androstan-3 beta, 17 beta-diol is generally considered a weak or inactive androgen, this effect may function to decrease dihydrotestosterone secretion by Leydig cells and/or to reduce the availability of this androgen in responsive tissues.

Metabolism of androgens in the seminal vesicles and the different lobes of the prostate in young mature rats

Oxidation and reduction of 4-androstene-3,17-dione (androstenedione), 17 beta-hydroxy-4-androsten-3-one (testosterone), 17 beta-hydroxy-5 alpha-androstan-3-one (DHT), 5 alpha-androstan-3 alpha,17 beta-diol (3 alpha-A'diol) and 5 alpha-androstane-3 beta,17 beta-diol (3 beta-A'diol) were measured in homogenates from ventral (VP), dorsal (DP) and lateral prostate (LP), the coagulating gland (CG) and seminal vesicle (SV) of the intact sexually mature rat using NAD(H) or NADP(H) as cofactors. The specific activity of the various enzymes varied significantly between the different organs. 5 alpha-Reductase activity was highest in the DP and the CG, and undetectable in the LP. 17 beta-Hydroxysteroid oxidoreductase (17 beta-HSOR) activity was mainly confined to the LP. 3 alpha-Hydroxysteroid oxidoreductase (3 alpha-HSOR) activity was also highest in the LP. In the VP the highest 3 alpha-HSOR activity was recorded using NAD(H) as cofactor. In the other organs, similar or higher enzymatic activities were measured using NADP(H) as added cofactor. 3 beta-Hydroxysteroid oxidoreductase (3 beta-HSOR) activity was high in the LP and low or undetectable in the other tissues. Our results indicate that isoenzymes of 3 alpha-HSOR, 3 beta-HSOR and 17 beta-HSOR are present in the accessory sex organs of the rat.

Age dependent changes in androgen metabolism in the rat prostate

Oxidation and reduction of androstenedione, testosterone, dihydrotestosterone (DHT), 5 alpha-androstan-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol (3 alpha- and 3 beta-A'diol) were measured in homogenates from the ventral prostate (VP), dorsal prostate (DP), lateral prostate (LP), the coagulating gland (CG) and seminal vesicles (SV) in intact rats of different ages from young mature (3-6 months) to senescent rats (20-30 months). Some very old intact rats (30-32 months) were treated with testosterone in order to rule out the effect of this hormone on androgen metabolism. The enzymatic activities for young mature rats were significantly altered by increasing age, both with regard to differences between the various organs as well as differences in cofactor requirement. With increasing age, the specific activity of most enzymes gradually decreased. With testosterone as substrate, 5 alpha-reductase activity was significantly reduced in the old rats in all tissues studied and was undetectable in the oldest animals in the VP and the SV. On the other hand, 5 alpha-reductase could not be recorded in any tissue in any tissue in old rats when androstenedione was the substrate. 3 alpha-Hydroxysteroid oxidoreductase (3 alpha-HSOR) in the VP was the only enzyme which did not decrease in activity by increasing age. In the other lobes this enzyme activity decreased similar to 3 beta-hydroxysteroid oxidoreductase (3 beta-HSOR) and the 17 beta-hydroxysteroid oxidoreductase (17 beta-HSOR) activity. Administration of testosterone to old rats increased the specific activity of most of the enzymes studied.

Ethanol directly increases dihydrotestosterone conversion to 5 alpha-androstan-3 beta,17 beta-diol and 5 alpha-androstan-3 alpha,17 beta-diol in rat Leydig cells

The direct effect of ethanol on dihydrotestosterone (DHT) conversion to 5 alpha-androstan-3 beta,17 beta-diol (3 beta-diol) and 5 alpha-androstan-3 alpha,17 beta-diol (3 alpha-diol) by adult rat Leydig cells was examined. Concentrations of ethanol comparable to blood levels of alcoholic men (2.2 - 65 mM) increased DHT conversion to 3 beta - and 3 alpha-diol, in direct relation to the dose of ethanol added; a 2-fold or greater stimulation was observed. Because this effect was blocked by 4-methylpyrazole or a saturating NADH concentration, these results suggest that this action is mediated by Leydig cell alcohol dehydrogenase activity. These results may have significant impact in the testis and/or other DHT sensitive tissues because ethanol may decrease the availability of the proposed active androgen.

Effects in vitro of medroxyprogesterone acetate on steroid metabolizing enzymes in the rat: selective inhibition of 3 alpha-hydroxysteroid oxidoreductase activity

The effects of 6 alpha-methyl-17 alpha-acetoxy-4-pregnene 3,20-dione (MPA) on the activity of different steroid metabolizing enzymes in vitro were investigated in several organs in the rat. MPA seems to be a potent inhibitor of 3 alpha-reduction of 17 beta-hydroxy-5 alpha-androstan-3-one (Dht) in homogenates of the testis, ovary, epididymis, prostate, kidney and the adrenal glands. In testicular homogenates MPA acts like a competitive inhibitor of the 3 alpha-reduction of Dht, with Ki of 0.42 [microM]. MPA seems to be a selective inhibitor of 3 alpha-hydroxysteroid oxidoreductase in numerous organs. Steroid metabolizing enzymes like 5 alpha-reductase, 7 alpha-hydroxylase, 3 beta-hydroxysteroid oxidoreductase and 17 beta-hydroxysteroid oxidoreductase were not inhibited by MPA under the conditions of incubation employed in these studies.

C-19-steroid 7 alpha-hydroxylation by rat testes. Isolation and identification of: 7 alpha, 17 beta-dihydroxy-5 alpha-androstan-3-one, 5 alpha-androstan-3 alpha, 7 alpha, 17 beta-triol and 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol

From incubations of testosterone with rat testicular homogenates in the presence of a NADPH-generating system, the following 7 alpha-hydroxylated metabolites could be isolated and identified: 7 alpha, 17 beta-dihydroxy-4-androsten-3-one (7 alpha-hydroxy-testosterone), 7 alpha-17 beta-dihydroxy-5 alpha-androstan-3-one (7 alpha-hydroxy-Dht), 5 alpha-androstan-3 alpha, 7 alpha, 17 beta-triol (7 alpha-hydroxy-3 alpha-A'DIOL) and 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol (7 alpha-hydroxy-3 beta-A'DIOL). To our knowledge this is the first demonstration of the formation of 5 alpha-reduced-7 alpha-hydroxylated metabolites of testosterone in the male gonad. These 5 alpha-reduced-7 alpha-hydroxylated metabolites could also be isolated after incubations of 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-A'DIOL) with testicular homogenates in the presence of A NADPH-generating system. Measured as the sum of 7 alpha-hydroxy-testosterone, 7 alpha-hydroxy-Dht. 7 alpha-hydroxy-3 alpha-A'DIOL and 7 alpha-hydroxy-3 beta-A'DIOL formed using testosterone as substrate, total 7 alpha-hydroxylase activity was six times higher in testes of mature rats than in testes from animals 23 days old. With 3 alpha-A'DIOL as substrate total 7 alpha-hydroxylase in the mature testis was about three times greater than in the sexually immature testis.

Synthesis and androgen effects of 7 alpha,17 beta-dihydroxy-5 alpha-androstan-3-one, 5 alpha-androstan-3 alpha,7 alpha,17 beta-triol and 5 alpha-androstane-3 beta,7 alpha,17 beta-triol

The steroids 7 alpha,17 beta-dihydroxy-5 alpha-androstan-3-one (7 alpha-hydroxy-Dht), 5 alpha-androstan-3 alpha,7 alpha,17 beta-triol (7 alpha-hydroxy-3 alpha-A'DIOL) and 5 alpha-androstane-3 beta,7 alpha,17 beta-triol (7 alpha-hydroxy-3 beta-A'DIOL) have been synthetized from 7 alpha,17 beta-dihydroxy-4-androsten-3-one (7 alpha-hydroxy-testosterone). The effect of administering 7 alpha-hydroxy-Dht, 7 alpha-hydroxy-3 alpha-A'DIOL or 7 alpha-hydroxy-3 beta-A'DIOL on serum levels of LH, FSH and on ventral prostate and seminal vesicle weight were investigated in gonadectomized adult male rats. Each steroid was administered for seven days in a dose of 300 micrograms per day. No suppression of serum LH or FSH levels was recorded following injections of these 7 alpha-hydroxylated steroids to castrated rats, compared to castrated control rats receiving vehicle only. Administration of 7 alpha-hydroxy-Dht or 7 alpha-hydroxy-3 alpha-A'DIOL to castrated mature rats could maintain ventral prostate and seminal vesicle weights above that of castrated control rats. Administration of 7 alpha-hydroxy-3 beta-A'DIOL to castrated mature rats resulted in ventral prostate weights slightly above castrate control levels, while seminal vesicle weight in such rats were in the same range as castrated control rats. Intraperitoneal administration of testosterone or of 5 alpha-androstane-3 beta,17 beta-diol (3 beta-A'DIOL) to castrated rats maintained activity of the androgen dependent isoenzyme of acid phosphatase in the ventral prostate; 7 alpha-hydroxy-testosterone or 7 alpha-hydroxy-3 beta-A'DIOL showed, however, no effect on this enzymic activity.