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At least 19 recordsLinked to original sources
PubMed1979

Effects of cyproterone and cyproterone acetate on the adrenal gland in the rat: studies in vivo and in vitro.

Male Wistar rats were treated for three weeks with cyproterone (1.7 or 5.1 mg/day) or cyproterone acetate (2 or 6 mg/day). The adrenal weights of animals treated with either dose of cyproterone acetate were significantly less (P less than 0.001) than those of untreated animals. In contrast, the adrenal weights of animals treated with cyproterone did not differ from those of the controls. The concentrations of corticosterone in the plasma were significantly less (P less than 0.001) in both groups treated with cyproterone acetate compared with those of the controls; only the higher dose of cyproterone reduced the plasma concentration of corticosterone (P less than 0.001). Cyproterone acetate inhibited the rat adrenal 3beta-hydroxysteroid dehydrogenase-5-ene,4-ene-isomerase complex in vitro, with both pregnenolone and dehydroepiandrosterone as substrates. Analysis of the reaction rates suggested an uncompetitive mode of inhibition. These results suggest that in rats the antiandrogens cyproterone and cyproterone acetate may provoke adrenal insufficiency by inhibition of steroid biosynthesis. Furthermore, indirect evidence from the mass and morphology of the adrenal suggests that cyproterone acetate may also suppress production or secretion of ACTH by the pituitary gland.

Adrenal Glands↗
PubMed1977

Some effects of cyproterone and cyproterone acetate on the reproductive physiology of the male rat.

Male rats were treated with 5 or 20 mg cyproterone acetate/kg/day or 20 mg cyproterone/rat/day for 1, 2, 3, 4, or 5 weeks. There was some reduction in fertility with both compounds, the maximum effect occurring after 5 weeks with the higher dose of cyproterone acetate and after 2 weeks with cyproterone. A significant increase in testosterone levels was found after treatment with the high dose of cyproterone acetate by 1 week and with cyproterone by 2 weeks. Dose-dependent atrophy of the seminal vesicles occurred after treatment with cyproterone acetate; with cyproterone atrophy occurred at 1 and 2 weeks but approximated to control values at 3, 4 and 5 weeks. Epididymal weights were reduced with the high dose of cyproterone acetate but the low dose had little effect. Reduction in the weight of the testes was only observed after 5 weeks of treatment with the high dose of cyproterone acetate. Since plasma testosterone levels were not depressed below normal values, accessory sex organ regression evidently resulted from the local antiandrogenic action of the drugs. There was some indication of interference with the secretory and absorptive activity of the lining cells of the epididymis but in general treatment with either steroid caused only relatively small and variable changes in the composition of epididymal plasma.

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↗
PubMedDate not supplied

Cyproterone acetate: I. Microquantity releasing device of cyproterone acetate and its failure in inducing functional sterility in male rats.

Prasad and his coworkers emphasized that microquantities of cyproterone acetate (CPA) when continuously available developed functional sterility in male rats by interfering the epididymal physiology. In our experimental rats either 2 or 3 capsules containing CPA as per the specification of Prasad were implanted subcutaneously and left for 300 and 250 days, respectively. Fertility test was made every month and it was observed that all the experimental animals were able to impregnate female rats throughout the experiment. Excepting the epididymis the weight of testes and other accessory glands did not differ from the controls in the animals which had 2 CPA capsules for 300 days; On the other hand, the animals which received 3 CPA capsules for 250 days showed significant reduction in weight of all the acessory glands including the testes.

Animals↗
PubMed1976

Cyproterone-mediated stimulation of delta-aminolevulinic acid synthetase in chick embryo liver cells.

In cultured chick embryo liver cells, cyproterone and cyproterone acetate, synthetic anti-androgenic steroids, were found to be potent inducers of mitochondrial delta-aminolevulinic acid (ALA) synthetase, the rate-limiting enzyme in the heme biosynthetic pathway. Both steroids produced a detectable increase in enzyme activity at 5 muM and a maximal stimulation, 36-fold for cyproterone and 29-fold for cyproterone acetate, at 55 muM. The dose-response curves of the steroids differed, however, in that cyproterone acetate produced a greater mean stimulation of the enzyme at concentrations less than approximately 25 muM, whereas, at higher concentrations, cyproterone was the more effective inducer. Increased activity of ALA synthetase was not apparent until about 12 hours after the addition of cyproterone, and maximal activity was not achieved until 20-24 hours. The induction of ALA synthetase by these anti-androgens was prevented by actinomycin D, cordycepin, anisomycin, cycloheximide, and puromycin. These results suggest that new RNA and protein synthesis are necessary for enzyme induction. The cyproterone-mediated induction of the enzyme was inhibited 50% by 2 muM heme, the putative physiological inhibitor of ALA synthetase. These antiandrogens, unlike other potent steroid inducers of this enzyme in chick embryo liver, do not possess either a 5beta-pregnane or 5beta-androstane nucleus. The stimulation of hepatic ALA synthetase represents the first example of a direct effect of these steroids on enzyme induction.

5-Aminolevulinate Synthetase↗
PubMed1976

[Bioavailability and pharmacokinetics of 14C-cyproterone acetate after administration as a 50-mg tablet (author's transl)].

Four male volunteers were each given a 50 mg oral dose of methylene-14C-labelled cyproterone acetate in a formulation largely identical to the commercial preparation Androcur Tablets. A further 3 volunteers were each given 10 mg of the 14C-labelled compound by intramuscular injection. Plasma samples were obtained and urine and faeces collected quantitatively from each volunteer up to 10 days post administration. 1. Absorption of the 50 mg of cyproterone acetate administered in the form of Androcur Tablets was largely complete. 2. The maximal plasma level of 400 +/- 40 ng cyproterone acetate equivalents/ml of plasma, calculated from the 14C activity, was found 3,8 +/- 0,5 hours after oral administration. By 10 hours post administration the plasma level had declined with a half-life of 7,9 +/- 2,5 hours (distribution and elimination). The fictitious distribution volume assignable to this process amounted to 140 +/- 40% of body weight. Plasma 14C-activity then decreased with a half-life of 1,8 +/- 0,2 days, which was consistent with elimination. 3. The labelled substance was almost completely extractable from plasma and could be separated by chromatography into 2 fractions of about equal size: cyproterone acetate and one metabolite. 4. Orally administered cyproterone acetate was eliminated with a half-life of 1,6 +/- 0,1 days. By 10 days post administration 33 +/- 6% of the dose had been detected in urine and 60 +/- 8% in faeces. Up to this time total elimination amounted to 93 +/- 5% of the dose. 5. After intramuscular injection of 10 mg of cyproterone acetate the half-life for absorption from the muscular depot was 7,0 +/- 0,2 hours. Between 2 and 10 days post administration there was a uniform decrease in plasma level and urinary elimination with half-life of 2,3 +/- 0,1 days and 2,1 +/- 0,2 days respectively. By the end of the trial 34 +/- 5% of the dose had been eliminated with urine and 57 +/- 6% with faeces.

Administration, Oral↗
PubMed1975

Metabolism and mode of action of androgens in target tissues of male rats. V. Uptake and metabolism of cyproterone acetate and its influence on the uptake and metabolism of testosterone and 5alpha-dihydrotestosterone in target organs and peripheral tissues.

In order to get more information on the mode of action of anti-androgens, two series with low but biologically active doses of cyproterone acetate were started. In the first experiments 12 mug of [3H]cyproterone acetate was injected intravenously into adult rats castrated 3 days before treatment. Thirty min after injection the radioactivity uptake in the target organs and other tissues was measured. The metabolites were separated by thin layer chromatography. A large pool of radioactivity could be shown in the liver. Thin layer chromatography revealed that in this pool cyproterone acetate had been converted by more than 80% to one metabolite. In blood plasma, too, the metabolite accounted for the major part of radioactivity. When compared to skeletal muscle, the prostate, seminal vesicles, and m. bulbocavernosus and m. levator ani accumulated more radioactivity. Within 30 min unchanged cyproterone acetate was retained selectively thus showing its relative high affinity to target organs. In a second experimental series, adult castrated male rats were given 10 mug of cyproterone acetate intravenously 30 min before the injection of [3H]testosterone or [3H]5alpha-dihydrotestosterone. Under this condition androgen uptake in target tissues was reduced to about 70% of the control values. The data parallel the results of in vivo studies on cytosol receptor displacement of androgens by cyproterone acetate. In agreement with previous investigators no significant influence of the anti-androgen on androgen metabolism was observed. The importance of the findings concerning the mode of anti-androgen action is discussed.

Adipose Tissue↗
PubMed1991

Use of cyproterone acetate in prostate cancer.

Cyproterone acetate is a progestational antiandrogen with potent antigonadotropic activity that results in rapid suppression of serum testosterone. Used as a single agent, cyproterone acetate yields a total androgen blockade. It may be combined with low-dose diethylstilbestrol, orchiectomy, or LHRH agonists to improve, in theory, the results of such therapy. In clinical testing, cyproterone acetate has proved equivalent to diethylstilbestrol with markedly less toxicity. It is useful in conjunction with LHRH agonists, either transiently to block the flare phenomenon, or continuously to block peripheral androgen receptors; the necessity for this latter action has not yet been proved. Cyproterone acetate may afford transient objective improvement in patients not responding to other forms of hormone deprivation. Experience in this role is limited. The drug may be used to suppress the hot flushes associated with orchiectomy or LHRH agonist therapy. Cyproterone acetate induces local tumor regression; owing to its reversible effects, it is useful as neoadjuvant or adjuvant androgen withdrawal therapy in patients with lower-stage disease undergoing radical surgery or radiotherapy. Adverse effects are mostly those related to hormone withdrawal, namely, impotence, infertility, and lassitude. Gynecomastia and breast tenderness occur in less than 18% and cardiovascular complications in approximately 10% of treated men.

Androgen Antagonists↗
PubMed1979

Plasma levels of active ingredients after single and repeated administration of a new oral contraceptive containing 2 mg of cyproterone acetate and 50 micrograms of ethinyl estradiol (DIANE) to five young women.

Peripheral plasma from five young women was analyzed for cyproterone acetate and ethinyl estradiol during a period of 96 hours duration after single oral intake of a coated tablet of DIANE (2 mg of cyproterone acetate + 50 micrograms of ethinyl estradiol), and during a treatment cycle of 21 days during which the formulation was given daily. Radioimmunoassays were utilized for quantifications. A maximum concentration of 11.0 +/- 3.4 ng of cyproterone acetate/ml plasma was found 1.6 +/- 0.6 hours after a single administration of DIANE. Postmaximal disposition took place in two phases with half-lives of 1.9 +/- 0.6 hours and 2.2 +/- 0.2 days. The maximum level of 0.08 +/- 0.03 ng of ethinyl estradiol/ml plasma was found 1.6 +/- 0.6 hours after such single administration. Following commencement of a daily oral intake of DIANE a steady state was reached by the 5th to 8th days, during which 24 hours after each dose cyproterone acetate concentrations were found to be 2.4 +/- 0.7 times higher than at the corresponding time after a single administration. Accordingly, after the first third of the 21 day treatment cycle an almost constant plasma level was reached indicating an equilibrium of intake and elimination. Except for a change in the mean terminal half life after multiple dosing, there was evidently no change in the kinetics of cyproterone acetate. No pointers to an accumulation of ethinyl estradiol upon daily administration of DIANE could be found.

Adult↗
PubMed1979

Effect of cyproterone acetate on the genital organs of female rats.

Effects of cyproterone acetate, a synthetic steroidal compound, on the reproductive organs of female rats have been investigated. This agent causes reduction in ovarian weights indicative of suppression of pituitary gonadotrophins. Oestrogenic nature of cyproterone acetate was investigated in intact and ovariectomized animals taking uterine weight, vaginal keratinization and other oestrogen sensitive biochemical parameters. Cyproterone acetate in ovariectomized animals induced vaginal keratinization, increase in uterine weight and uterine protein, RNA, glycogen and sialic acid contents. These effects were parallel to the effect of oestradiol dipropionate in ovariectomized animals, thus indicating oestrogenic activity cyproterone acetate. The histological and biochemical parameters lead to the conclusion that cyproterone acetate possessed antifertility property due to its inherent oestrogenic nature.

Adrenal Glands↗
PubMed1979

Effect of cyproterone acetate on the reproductive system of the female rat. A histological review.

Effects of cyproterone acetate, a synthetic steroidal compound, on the reproductive organs of female rats have been investigated. This agent caused reduction of ovarian weights indicative of suppression of pituitary gonadotrophins. Oestrogenic nature of cyproterone acetate was investigated in intact and ovariectomized rats taking uterine weight and vaginal keratinization as an index of oestrogenicity. Cyproterone acetate in ovariectomized animals induced vaginal keratinization and increased the uterine weights. These effects were parallel to the effect of oestradiol dipropionate in ovariectomized animals, thus indicating oestrogenic activity of cyproterone acetate. We may conclude that the above compound caused antifertility effects due to its oestrogenic nature at the dose level of 2 mg/alternate day in rats when the compound was administered subcutaneously.

Animals↗
PubMed1975

Effect of antiandrogen cyproterone acetate on the action of testosterone on mouse kidney.

The loss of endogenous testosterone in castrated male mice leads to a marked decrease in seminal vesicle and kidney tissue weight. 21 days' administration of exogenous testosterone abolished the effect of castration on the seminal vesicles and kidney tissue. The antiandrogen cyproterone acetate produced significant changes in the target tissue for androgens, i.e. in the seminal vesicles. In every case it blocked the action of both exogenous and endogenous testosterone on the seminal vesicles, but failed to block the "renotropic" action of testosterone, expressed as relative kidney weight. Contrary to its effect on the seminal vesicles, it did not influence relative kidney weight in normal animals. It likewise did not block the effect of exogenous testosterone on kidney tissue. The mechanism of the action of cyproterone acetate in androgen-dependent tissues is known to consist in inhibition of androgen binding to specific cell receptors in the target tissues. Some of the specific androgen receptors in mouse kidney are evidently different in character from those in the accessary sex glands, that being the reason why cyproterone acetate has an antiandrogenic, but not an antirenotropic effect. In agreement with experiments on rats, adrenal weight also decreases in mice after the administration of cyproterone acetate.

Animals↗
PubMed1977

Estrogenic and antifertility effect of cyproterone acetate in female gerbils, meriones hurriane Jerdon.

Effects of cyproterone acetate, a steroidal synthetic compound, on the reproductive organs of female gerbils have been investigated. This agent causes reduction of ovarian weights indicative of suppression of pituitary gonadotrophins. Estrogenic nature of cyproterone acetate was investigated in intact and ovariectomized gerbils taking uterine weight, vaginal keratinization and glycogen contents are parameters of estrogenic action. Cyproterone acetate in ovariectomized gerbils induced vaginal keratinization, increase in uterine weight, protein, RNA, glycogen and sialic acid contents of uterus, thus indicating an estrogenic activity. The histological and biochemical parameters lead to the conclusion that cyproterone acetate possesses estrogenic properties.

Animals↗