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Results for “Cyproterone Acetate”

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At least 19 recordsLinked to original sources
PubMed1985

On the site of action of the anti-adrenal steroidogenic effect of cyproterone acetate.

Cyproterone acetate (CA) inhibited 1-24 ACTH (50 ng/l)-stimulated cortisol production by dispersed guinea-pig adrenal cells in a dose-related manner. Inhibition occurred over the range 10(-6) to 5 X 10(-5) moles/l. The concentration of drug which induced 50% inhibition was 4.6 X 10(-6) moles/l. The sites of action of this anti-steroidogenic effect have been established. Dispersed adrenal cells were challenged with the cortisol precursor steroids (all at 10(-5) moles/l) pregnenolone (Pe), 17 alpha hydroxypregnenolone (17-OH Pe), 17 alpha-hydroxyprogesterone (17-Po), and 11 deoxycortisol or 1-24 ACTH (100 ng/1) in the absence and presence of increasing concentrations of CA (10(-5) to 10(-4) moles/l). In the absence of drug, the steroid precursors or ACTH provoked cortisol secretion greater than 10-fold that secreted by cells incubated in their absence. ACTH-stimulated cortisol secretion was inhibited greater than 68% at concentrations of CA greater than 10(-5) moles/l. CA (10(-5) moles/l) had no significant effect on steroid-stimulated cortisol production when the delta 4, 3 ketosteroids 17-OH Po and 11-deoxycortisol were used, but depressed secretion by greater than 61% (P less than 0.001) when the delta 5 3 beta hydroxysteroids (Pe, 17-OH Pe) were employed. Increasing CA concentrations to 10(-4) moles/l had little effect on cortisol secretion provoked by 11-deoxycortisol, but significantly (P less than 0.05) depressed cortisol secretion stimulated by 17-OH Po. These results suggest that the major site of action of CA is delta 5, 3 beta hydroxysteroid dehydrogenase (3 beta-HSD) with a secondary effect on 21-hydroxylase activity. To confirm these findings cortisol secretion provoked by 17, 21, dihydroxypregnenolone (17, 21 diOH Pe) and 21 deoxycortisol (21-DOC) was measured in the absence and presence of increasing concentrations of CA. At the lowest concentration of CA (5 X 10(-6) moles/l), cortisol secretion provoked by 17, 21 diOH Pe was inhibited by 28% (P less than 0.01) whereas secretion provoked by 21-DOC was not significantly affected. At the highest concentration of CA (10(-4) moles/l), the relative inhibition was 80% for 17, 21 diOH Pe and 38% for 21-DOC. We conclude that cyproterone acetate inhibits adrenal steroidogenesis at both 3 beta-HSD and 21-hydroxylase, the degree of inhibition being more pronounced at 3 beta-HSD.

3-Hydroxysteroid Dehydrogenases↗
PubMed1979

Histological characteristics of the human testis after long-term treatment with cyproterone acetate.

Cyproterone acetate, an antiandrogen drug, is used to reduce mammalian fertility. Effects on the human testis are controversial. Findings in this study reveal that long-term treatment-7 months with 200 mg/day-leads to disappearance of the germinal cells and to Sertoli cells with either a normal or undifferentiated aspect as well as involution of the Leydig cell. Some pathogenetic hypotheses on the action of cyproterone acetate upon human spermatogenesis are discussed.

Cyproterone↗
PubMed1987

Post-heparin plasma hepatic lipase activity as predictor of high-density lipoprotein response to progestogen therapy: studies with cyproterone acetate.

Cyproterone acetate (CPA) was administered to 13 menstruating women from day 14 to day 27 of the cycle at a dose of 5 mg/day. Serum lipoprotein lipid levels and postheparin plasma lipase activity were determined on day 27 of the cycle before treatment and during two treatment cycles. No significant changes were observed in hepatic lipase activity or in very-low-density (VLDL) or low density lipoprotein (LDL) concentrations. However, analysis of high-density-lipoprotein (HDL) subfractions by precipitation demonstrated a significant reduction in HDL2 cholesterol (-24%, P less than 0.05) during cyproterone acetate treatment. It is suggested that this change is related to oestrogen deficiency induced by inhibition of luteinizing hormone (LH) secretion.

Adult↗
PubMed1990

Determination of megestrol acetate and cyproterone acetate in serum of patients with advanced breast cancer by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method with ultraviolet detection of megestrol acetate and cyproterone acetate in human sera is described. The proposed assay is linear up to 1400 ng/ml (r = 0.999) and has a detection limit of 5 ng/ml. Recoveries of both compounds in spiked sera were ca. 95%; inter-assay coefficients of variation were 4.0 and 3.1% and intra-assay values were 1.3 and 1.4%, respectively. For validation of the method we also developed a gas chromatographic-mass spectrometric method for both steroids. The results obtained by the two methods showed good correlation: for megestrol acetate r = 0.98, n = 31, p less than 0.0001, and for cyproterone acetate r = 0.94, n = 0, p less than 0.0001. Large inter-individual differences in the serum concentrations of both substances were found in groups of patients with metastatic breast cancer receiving the same oral load of either steroid.

Antineoplastic Agents↗
PubMed1995

DNA repair synthesis and DNA fragmentation in primary cultures of human and rat hepatocytes exposed to cyproterone acetate.

Cyproterone acetate (CPA), a synthetic steroid used in human therapy, has recently been shown to cause DNA damage in cultured rat hepatocytes and in rat liver. In the present study we have investigated whether CPA also induces genotoxic effects in human hepatocytes. Genotoxicity of CPA was determined by measuring the capability of the compound for inducing DNA repair synthesis and for causing the formation of DNA single-strand breaks. Autoradiography and alkaline elution were used to quantitate DNA repair and DNA fragmentation, respectively. Exposure of hepatocytes to CPA for 20 h induced DNA repair synthesis in two hepatocyte preparations derived from males and in four of the five preparations derived from females. In cultures from some donors, induction of repair was detected at 1 microM CPA, the lowest concentration tested. The maximum effect generally occurred at 10-20 microM. Only a very slight increase in the frequency of DNA single-strand breaks was found following exposure of the hepatocytes to 50 microM CPA for 20 h. For comparative purposes, the effects of CPA on DNA repair and DNA fragmentation were also determined in cultured rat hepatocytes. A strong induction of DNA repair synthesis, but only a slight enhancement in DNA fragmentation was observed in CPA-treated hepatocytes derived from female rats. These results indicate that the measurement of repair is a more sensitive indicator for the genotoxicity of CPA than the measurement of DNA fragmentation. No genotoxic effects of CPA were detectable in hepatocyte cultures derived from male rats. The present findings show that CPA is genotoxic in human hepatocytes and that the striking sex difference in the genotoxicity of CPA in rat cells is not observed with human cells.

Aged↗
PubMed1984

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.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1992

A double-blind placebo controlled trial of medroxyprogesterone acetate and cyproterone acetate with seven pedophiles.

Seven of ten pedophiles in hospital completed a double-blind, placebo-controlled two-dose comparison of medroxyprogesterone acetate and cyproterone acetate. Sequential measures during the 28 week study were: patient self-reports, nurses' observations, phallometry, hormone levels and side-effects. The drugs, which performed equivalently, reduced sexual thoughts and fantasies, the frequency of early morning erections on awakening, the frequency and pleasure of masturbation, and level of sexual frustration. Penile responses were also reduced but to a lesser degree and were more variable. Serum testosterone FSH and LH all declined during drug administration, but by the end of the final placebo phase had essentially returned to (or exceeded) pre-drug values. Our experience suggests that only a minority of pedophiles are likely to accept libido-reducing drugs.

Adult↗
PubMed1980

Treatment of hirsutism, acne and alopecia with cyproterone acetate.

Cyproterone acetate, combined with ethinyl estradiol, was administered to 60 women (mean age: 25 years) suffering from hirsutism, acne and alopecia for 3--39 months. The rate of success was 94% for acne, 85% for hirsutism and 55% for alopecia. These results are comparable to those already reported. No correlation was found between the degree of the disease or plasma levels of testosterone, androstenedione, respectively urinary 17-cetosteroids, and the effectiveness of the treatment. Side effects were rare and identical in frequency and nature to those encountered during treatment with estrogen-containing contraceptives.

17-Ketosteroids↗
PubMed1985

15-Hydroxycyproterone acetate and cyproterone acetate levels in plasma and urine.

15 beta-Hydroxycyproterone acetate (15HOCPA) and cyproterone acetate (CPA) have been quantitated in human plasma and urine by a selective high-performance liquid chromatographic assay. The levels of 15HOCPA in plasma are generally twice those of its precursor CPA, although both compounds appear to have similar clearance rates. Approximately 6% of the dose is excreted into the urine, predominantly (greater than 90%) as the free form of 15HOCPA and CPA.

Chromatography, High Pressure Liquid↗
PubMed1977

Changes in insulin receptor concentration in rat fat cells following treatment with the gestagens clomegestone acetate and cyproterone acetate.

Specific insulin receptors were measured in isolated fat cells of rats after treatment with clomegestone acetate. Under conditions when peripheral insulin insensitivity was observed, the number of insulin receptors was simultaneously reduced. A similar though smaller decrease in insulin receptor concentration was seen in rats after treatment with cyproterone acetate, a compound which did not cause insulin resistance. It is concluded that the gestagenic compounds tested decrease insulin receptor concentration. Only drastic reduction of the number of binding sites results in significant perturbations of carbohydrate metabolism.

Adipose Tissue↗
PubMed1995

Identification of 3 alpha-hydroxy-cyproterone acetate as a metabolite of cyproterone acetate in the bile of female rats and the potential of this and other already known or putative metabolites to form DNA adducts in vitro.

Cyproterone acetate (CPA) is a synthetic steroid hormone used in the therapy of prostate cancer in men and different forms of acne and hirsutism in women. CPA has been shown by 32P-postlabeling analysis to bind covalently to hepatic DNA of rats in vivo and in vitro. A prerequisite for DNA adduct formation of CPA is metabolic activation of the drug to a reactive intermediate. In the present study bile was collected from [3H]CPA-treated female rats and, following chromatographic separation of bile extracts, fractions of the eluate were examined for the presence of reactive metabolites which were able to form adducts with calf thymus DNA in vitro. The formation of adducts was detected by 32P-postlabeling analysis. One major metabolite of CPA present in the bile extracts was isolated and, following a thorough structural elucidation by mass spectrometry and 1H-NMR, this metabolite was identified as 3 alpha-hydroxy-cyproterone acetate (3 alpha-OH-CPA). This metabolite was able to form the same major adduct in vitro which has been observed before in CPA-treated rats in vivo and in rat hepatocytes in vitro. A number of already known or putative metabolites of CPA were available as authentic standards and these were also examined for their propensity to form adducts in vitro. A positive result was obtained for 3-O-acetyl-cyproterone acetate, which formed the same major adduct as 3 alpha-OH-CPA. However, the presence of this putative metabolite in rat bile could not be demonstrated. Besides 3 alpha-OH-CPA, additional reactive metabolites of CPA were present in the bile extracts, however, since these were only minor components, their chemical structures could not be elucidated.

Animals↗
PubMed1977

Isolation and identification of 15-beta-hydroxy cyproterone acetate as a new metabolite of cyproterone acetate in dog, monkey and man.

15-beta-hydroxy cyproterone acetate could be identified by thin layer chromatography, mass spectrum, NMR and IR spectrum as a major unconjugated metabolite of cyproterone acetate in plasma and urine of dog, monkey and man. This metabolite has been found to interferein the Mattingly method for the determination of 11-hydroxy-corticosteroids which suggests, that this method is inadequate in controling the adrenal function of subjects treated with cyproterone acetate.

Animals↗