Françoise Wright

Androgen metabolism in hirsute patients treated with cyproterone acetate

Cyproterone acetate (CPA) in association with percutaneously administered estradiol has been used for the treatment of 150 hirsute patients for periods ranging from 6 months to 3 years. A spectacular clinical improvement ensued. Plasma testosterone (T) and androstenedione (A) fell from 69.0 +/- 24 to 33.0 +/- 8 and 210 +/- 103 to 119 +/- 25 ng/dl (mean +/- SD) respectively after 3 months of treatment and remained low thereafter. In contrast, T glucuronide (TG) and 3 alpha-androstanediol (Adiol) remained high during the whole course of treatment: 37 +/- 9 and 115 +/- 43 micrograms/24 h respectively. In vitro T 5 alpha-reductase activity (5 alpha-R) in pubic skin decreased from 147 +/- 34 to 79 +/- 17 fmol/mg skin after 1 year of treatment. To elucidate the discrepancy between plasma and urinary androgens levels, T production rate (PR) and metabolic clearance rate (MCR) were measured with the constant infusion technique in 7 patients before and after 6 months of treatment. PR decreased from 988 +/- 205 to 380 +/- 140 micrograms/24 h (mean +/- SD). In contrast MCRT increased from 1275 +/- 200 to 1632 +/- 360 1/24 h; this increase in MCRT explains the striking plasma T concentration fall and the high TG and Adiol excretion relative to the decrease in PR. Antipyrine clearance rate (n = 8) increased from 36.3 +/- 5.2 to 51.5 +/- 7.4 ml/min whereas 6 beta hydroxycortisol remained unchanged. In conclusion, CPA acts through several mechanisms: (1) it lowers the androgen input to the target cells by (a) depressing T production through its antigonadotropic effect and (b) accelerating T metabolic inactivation due to a partial enzymatic inducer effect on the liver; (2) at the target cell level it competes with any remaining T for the receptor binding sites; (3) the decrease in the androgen-dependent skin 5 alpha-R is a consequence of both actions of androgen suppression and androgen receptor blockade; it reinforces the antiandrogenic effect of CPA.

Control of sulfatase and sulfotransferase activities by medrogestone in the hormone-dependent MCF-7 and T-47D human breast cancer cell lines

In the present study, we explored the effect of the progestin medrogestone on the sulfatase and sulfotransferase activities in the hormone-dependent MCF-7 and T-47D human breast cancer cell lines. After 24 h incubation at 37 degrees C of physiological concentrations of estrone sulfate ([3H]-E1S: 5x10(-9) mol/l), it was observed that this estrogen was converted in a great proportion to E2 in both cell lines. Medrogestone significantly inhibits this transformation, at all the concentrations tested (5x10(-8) to 5x10(-5) mol/l), in both cell lines. The IC50 values were 1.93 micromol/l and 0.21 micromol/l in MCF-7 and T-47D cells, respectively. In another series of studies, after 24 h incubation at 37 degrees C of physiological concentrations of estrone ([3H]-E1: 5x10(-9) mol/l), the sulfotransferase activity was detectable in both cell lines. Estrogen sulfates (ES) are found exclusively in the culture medium, which suggests that as soon as they are formed they are excreted into the medium. Medrogestone has a biphasic effect on sulfotransferase activity in both cell lines. At low doses: 5x10(-8) and 5x10(-7) mol/l, this compound stimulates the enzyme by +73.5 and 52.7%, respectively, in MCF-7, and by 84.5 and 62.6% in T-47D cells. At high concentrations: 5x10(-6) and 5x10(-5) mol/l, medrogestone has no effect on MCF-7 cells, but inhibits the sulfotransferase activity in T-47D cells by -31.4% at 5x10(-5) mol/l. In conclusion, the inhibitory effect provoked by medrogestone on the enzyme involved in the biosynthesis of E2 (sulfatase pathway) in estrogen-dependent breast cancer, as well as the stimulatory effect on the formation of the inactive ES, support a probable anti-proliferative effect of this progestin in breast tissue. Clinical applications of these findings can open new therapeutic possibilities for this disease.

Selective venous catheterization in the evaluation of hyperandrogenism

Retrograde bilateral ovarian-adrenal vein catheterization was carried out in 16 patients with plasma testosterone levels exceeding 1.4 ng/ml (4.85 nmol/l). While pelvic ultrasonography and computerized axial tomographic scan failed to locate the androgen-producing ovarian tumors, catheterization led to a diagnosis of occult ovarian tumor in 5 patients, based on the observation of an abnormally-high and unilateral ovarian-peripheral vein testosterone gradient, which was subsequently confirmed histopathologically. In one case, unilateral elevation of the adrenal-peripheral vein testosterone gradient was found, complementing the ultrasonographic finding of an adrenal mass and confirming the diagnosis of a virilizing adrenal tumor. In the other 10 patients, gradient analysis ruled out an androgen-producing tumor, leading to the identification of nontumoral hyperandrogeny, such as a severe form of the polycystic ovary syndrome in the 6 premenopausal patients and of ovarian stromal and hilus cell hyperplasia in the 4 menopausal patients. In conclusion, appropriate indication of selective catheterization may considerably reduce the need for exploratory surgery and may help in selecting the adequate surgical approach.

DIFFERENT ASPECTS OF 5α‐REDUCTASE DEFICIENCY IN MALE PSEUDOHERMAPHRODITISM AND HYPOTHYROIDISM

The 5α‐reductase activity that mediates the transformation of testosterone to dihydrotestosterone in various anatomical sites of human beings, has been studied in different pathological conditions related to 5α‐reductase deficiency. We have studied two patients with male pseudohermaphroditism due to 5α‐reductase deficiency, four patients with the complete form of testicular feminization syndrome and four men with primary hypothyroidism. Results were compared with those obtained in seven normal men. In vivo: radioactive tracers of testosterone were administered to each subject by different routes: intravenous, oral and subcutaneous. The urinary metabolites of these labelled precursors were measured. The 5β: 5α ratios of 17‐ketosteroids (aetiocholanolone: 5α‐androsterone) and androstanediols (5β‐androstane‐3α, 17β‐diol: 5α‐androstane‐3α, 17β‐diol) were calculated in the urine recovered after each mode of administration of radioactive testosterone. When testosterone was administered subcutaneously these ratios were highly increased in one patient with male pseudohermaphroditism due to 5α‐reductase deficiency. In all the other patients, the ratios were found to be in the normal range for men. After oral administration of radioactive testosterone, both 5β: 5α ratios were very high in hypothyroid and in 5α‐reductase deficient patients. These results suggest that the defective 5α‐reductase activity observed in hypothyroid patients is only localized in the hepatic compartment. Conversely, in male pseudohermaphroditism, the 5α‐reductase defect might affect both hepatic and extra‐hepatic compartments. In vitro: the diagnosis of 5α‐reductase deficiency was confirmed in the two male pseudohermaphrodite patients after incubation with 3H testosterone of skin homogenates from the external genital area. No 5α‐reduction of testosterone occurred in the two skin specimens studied. In contrast, 5α‐reductase activity was normal in genital skin from hypothyroid and testicular feminization syndrome patients. In pubic skin, 5α‐reductase activity was absent in patients with testicular feminization syndrome. It was in the normal range in homogenates from hypothyroid patients and varied in the 5α‐reductase deficient patients. Based on these data, it may be postulated that the programming of hepatic and extrahepatic 5α‐reductase enzymes is fundamentally different. In addition, the enzyme that mediates the appearance of secondary sex characteristics seems to be androgen dependent, while the 5α‐reductases present in the external genital area and the liver are not androgen dependent.

Effect of medrogestone on 17β-hydroxysteroid dehydrogenase activity in the hormone-dependent MCF-7 and T-47D human breast cancer cell lines

Estradiol (E2) is one of the most important hormones supporting the growth and evolution of breast cancer. Consequently, to block this hormone before it enters the cancer cell, or in the cell itself, has been one of the main targets in recent years. In the present study we explored the effect of Medrogestone (Prothil) on 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activities of the hormone-dependent MCF-7 and T-47D human breast cancer cell lines. Using physiological doses of estrone ([3H]-E1: 5 x 10(-9) mol/l) this estrogen is converted in a great proportion to E2 in both cell lines. After 24 h of the cell culture, Medrogestone significantly inhibits this transformation in a dose-dependent manner by 39% and 80% at 5 x 10(-8) M and 5 x 10(-5) M, respectively in T-47D cells; the effect is less intense in MCF-7 cells: 25% and 55% respectively. The IC50 values are 0.45 micromol/l in T-47D and 17.36 micromol/l in MCF-7 cells. It is concluded that the inhibition provoked by Medrogestone on the reductive 17beta-HSD activity involved in the local biosynthesis of the biologically active estrogen estradiol, may constitute a new therapeutic approach for the treatment of breast cancer.

Androgen receptor in sexual differentiation

Androgens play an essential role in sexual differentiation and their action is mediated by the androgen receptor (AR). The normal AR is a soluble protein, highly thermolabile, with a mol. wt of 90 kDa and a pI of 5.2 as determined by 2 dimensional (2D) gel electrophoresis. It is regulated by androgens in culture conditions but the physiological relevance of this regulation remains controversial. The presence of a functional AR is an absolute requirement for male sexual differentiation and its absence results in complete insensitivity. However, androgen insensitivity (complete or partial) can develop in the presence of a normal androgen binding capacity and there is no correlation between the clinical and the biochemical findings. A number of qualitative abnormalities have been described to explain the failure of androgen action in these cases: they all emphasize the extreme instability of the abnormal AR. It is difficult at the present time to determine whether these abnormalities result from structural mutations of the AR gene, transcriptional or post-transcriptional abnormalities. Further elucidation of these defects awaits for an antibody and/or a cDNA probe for the AR.

A simple and reliable technique for separating the androgen receptor from testosterone-binding globulin in human tissues.

Abstract Ammonium sulfate precipitation, followed by Sepharose 4B column chromatography is used to separate the androgen receptor from contaminating testosterone-binding globulin in human foreskin cytosol. The binding specificity is checked by dihydrotestosterone and cyproterone acetate displacement. In addition, after the column, the tubes corresponding to the peak of receptor can be pooled and used in an assay. This simple and reliable technique should allow the study of the androgen receptor in human target tissues.

Androgen receptors in human skin cytosol: physiological and pathological variations

The androgen binding capacity has been measured in thé cytosol of genital and pubic skin of normal men and women and patients with disorders of androgen sensitivity. The binding capacity was highest in genital skin, but no differences were observed with age or sex. This, and the presence of a normal binding capacity in some patients with patent clinical insensitivity, suggests that the androgen receptor in human skin cytosol is not regulated by androgens.

Isoelectric focusing and 2D electrophoresis of the human androgen receptor.

Nuclear androgen receptors from cultured genital skin fibroblasts were analyzed by non-denaturing isoelectric focusing (IEF) in ultrathin polyacrylamide gels before and after photoaffinity labeling with [3H]methyltrienolone. Both reversibly and covalently labeled receptors focused at pH 5.28 +/- 0.20 when extracted from nuclei with high salt. Lowering of the salt concentration yielded, in both cases, a second species which focused at pH 7.16. This species became predominant when nuclei were sonicated in IEF sample buffer containing no salt, even after extensive nucleic acid digestion. Low salt cytosols from both prostate and foreskin focused as a single peak of pI: 4.93 +/- 0.31 which remained unchanged when KCl was added to the cytosol up to a concentration of 0.6 M. SDS-polyacrylamide gel electrophoresis of photoaffinity labeled receptors revealed labeled proteins with Mw 90-95 kDa. Two-dimensional electrophoresis of photoaffinity labeled nuclear receptors, extracted in low or high salt, showed that the two isoforms (pI 5.28 and 7.16) contain the same steroid-binding subunit with Mw 90-95 kDa. Nuclear receptors from 4 patients with the receptor positive form of the Complete Androgen Insensitivity Syndrome (CAIS, Rc+) were analyzed by non-denaturing IEF: a single species was observed, focusing at pH 6.0 whether in high or low salt conditions. These results indicate that the nuclear androgen receptor is an acidic protein with pI 5.28 and Mw 90-95 kDa under maximum protein dissociation conditions. When extracted under low salt conditions, it can be isolated in a neutral form (pI 7.16) suggesting its association with a nuclear protein. Receptors of (CAIS, Rc+) patients have an abnormal charge and show no pI shift upon lowering of the salt concentration suggesting that this shift could be a significant step in the mechanism of action of androgens.