Mechanism of action of 17 alpha-propyltestosterone in inhibiting hamster flank organ development.

Win 17,665 [topterone, (17 beta)-17-hydroxy-17-propylandrost-4-en-3-one] inhibited stimulation of flank organ development of castrated immature male hamsters by both testosterone and dihydrotestosterone, whereas progesterone inhibited the stimulation by only testosterone. Topical application of Win 17,665 on the flank organs of the male hamster did not cause any significant effect on testosterone metabolism of this tissue. In addition, there was no decrease in the lipogenic capacity of the flank organ. The evidence presented indicates that Win 17,665 exerts its antiandrogenic action by binding with the cytosolic androgen receptor(s) in the flank organ thus inhibiting the action of dihydrotestosterone.

Nivazol: a glucocorticoid in rats with only hypothalamic-pituitary-adrenal-inhibiting activity in primates.

The synthetic steroid nivazol lacks three of the substituents considered to be important for glucocorticoid activity, i.e. the 3-keto, the 11-hydroxy, and the 20-keto groups. Nevertheless, in the rat, nivazol has the activity profile of a glucocorticoid. After treatment of intact female rats with nivazol , the mean weights of the adrenals and thymus were lower than those in the vehicle-treated control group. The results were qualitatively and quantitatively similar to those obtained with methylprednisolone. Thymolysis as well as liver glycogen deposition were seen in adrenalectomized rats treated with nivazol , and eosinopenia and inhibition of carrageenan edema were noted in intact rats. In the rhesus monkey, treatment with nivazol resulted in a marked reduction in circulating cortisol levels and elimination of the diurnal pattern, although a dose 10 times that needed to reduce circulating cortisol levels did not produce eosinopenia or increase fasting blood glucose levels. Both eosinopenia and higher fasting blood glucose levels were seen after treatment with methylprednisolone. Nivazol did not prevent the ACTH-induced increase in circulating cortisol levels nor did it alter circulating aldosterone levels. Therefore, suppression of ACTH is the predominant if not the sole action of nivazol in the primate. Preliminary results in clinical trials suggest a similar activity profile in humans. Therefore, nivazol elicits numerous glucocorticoid activities in the rodent, but only the inhibition of the hypothalamic-pituitary-adrenal axis was observed in the primate. It is of special interest that the inhibition of the hypothalamic-pituitary-adrenal axis occurs without altering circulating aldosterone levels and without evidence of debilitating catabolic activity.

Oral progestational activity of spironolactone.

Spironolactone has progestational activity in the rabbit and rhesus monkey. It produced glandular development in the endometrium of the estrogen-primed immature female rabbit over the dosage range of 50 to 200 mg/kg and, at 400 mg/monkey, it delayed estrogen-withdrawal bleeding in ovariectomized monkeys and it inhibited menstruation in regularly cycling monkeys. These data are consistent with the menstrual irregularity and amenorrhea seen in women during treatment with spironolactone.

Isolation, synthesis, and biological activity of five metabolites of danazol.

Metabolites of danazol (17 alpha-pregna-2,4-dien-20-yno[2,3-d]isoxazol-17-ol), an orally effective pituitary gonadotropin inhibitory agent devoid of estrogenic and progestational activites, were isolated from urine of a female subject who had taken danzol orally at a dose of 800 mg/day for 7 days, The metabolites isolated were 17-hydroxy-17alpha-pregn-4-en-20-yn-3-one (11), 17-hydroxy-2alpha-(hydroxymethyl)-17alpha-pregn-4-3n-20-yn-3-one (5), 17-hydroxy-2-(hydroxymethyl)-17alpha-pregna-1,4-dien-20-yn-3-one(7), 6beta,17-dihydroxy-2alpha-(hydroxymethyl)-17alphapregn-4-en-20-yn-3-one(8), and 6beta, 17-dihydroxy-2(hydroxymethyl)-17alphapregna-1,4-dien-20yn-3-one(10). None of these metabolites exhibited pituitary inhibiting activity comparable to danazol.

PIP: Urinary metabolites of danazol (17alpha-pregna-2,4-dien-20-yno (2,3-delta)isoxazol-17-01), and inhibitor of pituitary gonadotropins, were isolated from a woman who had been taking the drug orally at a dose of 800 mg/day for 7 days. The isolated metabolites were 17-hydroxy-17alpha-pregn-4-en-20-yn-3-one, 17-hydroxy-2alpha-(hydroxymethyl)-17alpha-pregn-4-en-20-yn-3-one, 47-hydroxy-2-(hydroxymethyl)-17alpha-pregna-1,4-dien-20-yn-3-one, 6beta,17-dihydroxy-2alpha-(hydroxymethyl)-17alpha-pregn-4-en-20-yn-3-one and 6beta,17-dihydroxy-2-(hydroxymethyl)-17alpha-pregna-1,4-dien-20-yn-3-one. The pituitary inhibiting activity of these metabolites was less than that of danazol.

Non-steroidal glucocorticoid-like substances: receptor binding and in vivo activity.

Compounds of general structure I, prepared by a Diels-Alder reaction with diene 3, are relatives of the known potent glucocorticoid II but possess a markedly modified C- and D-ring environment. Despite these structural changes, 4, 5, 9, 10, 12a, 13, and 14 bound to the glucocorticoid receptor with an affinity which approximated that of the reference standard, 6-alpha-methylprednisolone. Four of these compounds not only exhibited antiinflammatory activity in the alpha-tocopherol pouch test but also exhibited marked adrenal suppression and other typical glucocorticoid properties at doses in the same range as the effective antiinflammatory doses.

Steroidogenesis inhibitors. 1. Adrenal inhibitory and interceptive activity of trilostane and related compounds.

Several methylated derivatives of trilostane were prepared. Methylation of C-4 or C-4 and C-17 changes this relatively selective adrenal inhibitor to compounds with increased ovarian/placental inhibitory activity with decreased adrenal inhibitory activity.

Fertility in the rhesus monkey following long-term inhibition of ovarian function with danazol.

Danazol was previously reported to be an oral contraceptive in the rhesus monkey at doses of 200 and 400 mg/monkey/day for 90 days. The drug is now shown to be an effective long-term inhibitor of ovarian function in the monkey. In the final 3 months of a 27-month period of treatment at a dose of 400 mg/monkey/day, the drug continued to be an effective oral contraceptive. During the 27-month treatment period, three of seven monkeys were amenorrheic and the remaining had only 16 of the 109 expected menstrual cycles. Following the discontinuation of medication, all seven monkeys conceived within 2 to 6 weeks. One monkey aborted early in pregnancy and the remaining six delivered normal, healthy infants at term. Therefore, following the discontinuation of long-term treatment with danazol in the monkey, there was rapid and complete return of normal ovarian function.

Inhibition of ovarian, placental, and adrenal steroidogenesis in the rhesus monkey by trilostane.

Trilostane inhibits adrenal, ovarian, and placental steroidogenesis when administered orally to rhesus monkeys. By inhibiting 3 beta-hydroxysteroid dehydrogenase activity, it causes an increase in circulating levels of pregnenolone. Trilostane reverses the stimulation of luteal progesterone production and the delay in onset on menstruation induced by human chorionic gonadotropin. In pregnant monkeys it reduces circulating progesterone levels and is an effective interceptive agent if given for 5 days beginning on day 16, 25, or 50 of gestation. Concurrent administration of progesterone prevents this interceptive effect. Trilostane reduces plasma cortisol levels at doses lower than those necessary to terminate pregnancy.

Interruption of pregnancy in rats by azastene, an inhibitor of ovarian and adrenal steroidogenesis.

Azastene (4,4,17alpha-trimethylandrost-5-eno[2,3-d]isoxazol-17-ol), when given orally to rats at a dose of 12 mg/kg once on day 10 of pregnancy, induced resorption of all fetuses and a precipitous decline of circulating progesterone levels in all test animals. The disruption of pregnancy was prevented by a single, concurrent, subcutaneous injection of progesterone (4 mg/rat). Thus, the interruption of pregnancy occurs via an acute, short-term, reversible progesterone withdrawal. The reduction of progesterone levels is brought about by competitive inhibition of ovarian 3beta-hydroxysteroid dehydrogenase activity. Despite its potency as an interceptive agent, azastene exhibited only moderate endocrine-related effects if given daily for 2 weeks to female rats at doses as high as 1000 mg/kg. Those effects were an increase in the number of vaginal estrous days and a dose-related increase in adrenal weight. The latter effect is consistent with the known adrenal inhibitory properties of this drug.

Interceptive activity of azastene in rhesus monkeys.

Azastene is an orally effective "luteolytic" agent in rhesus monkeys. In nonpregnant monkeys it reverses the human chorionic gonadotropin-stimulated increase in progesterone production and delay in the onset of menstruation, and, in inseminated monkeys, it prevents pregnancy if given for 5 days beginning on day 24 of the menstrual cycle. The drug is also effective in terminating pregnancy if given for 5 days beginning on approximately day 26, day 50, or day 80 of gestation. Concurrent progesterone administration prevents the interceptive action of the drug. Although azastene inhibits gonadal and placental progesterone production, it has no effect on cortisol production in monkeys and is devoid of apparent hormonal activity.

The interaction of nivazol with the glucocorticoid receptor from rat and rhesus monkey target tissues.

Steroid hormone receptor competition techniques were used to evaluate the glucocorticoid receptor binding properties of nivazol and its 11 beta-hydroxy derivative, Win 44577 in rat and monkey target tissues. These agents competitively inhibited the binding of 3H-dexamethasone to the glucocorticoid receptor from the liver and anterior pituitary from both rat and monkey with relative binding affinities of Win 44577 greater than dexamethasone greater than nivazol greater than cortisol in all cases. However, nivazol and Win 44577 had approximately twice the affinity for the anterior pituitary glucocorticoid receptor from both species. Neither compound demonstrated any significant binding to rat estrogen, progestin or androgen receptors. These results are consistent with a glucocorticoid receptor mediated mechanism of action for nivazol and Win 44577; however, the difference in the endocrine profile of nivazol in the rhesus monkey versus the rat does not appear to be due to a species selectivity in the affinity of nivazol for the glucocorticoid receptor from central or peripheral target tissue.

Trilostane, an orally active inhibitor of steroid biosynthesis.

Trilostane is a competitive inhibitor of 3beta-hydroxysteroid dehydrogenase. In vitro, the drug inhibits conversion of pregnenolone to progesterone but does not alter conversion of cholesterol to pregnenolone nor progesterone to corticoid hormones. When given orally to rats, trilostane inhibits corticosterone and aldosterone production and elevates circulating levels of pregnenolone at doses lower than those that produce adrenal hypertrophy or inhibit gonadal steroidogenesis.

Glucocorticoid/antiinflammatory activities of nonsteroidal phenylpyrazoles in the rat.

Six nonsteroidal phenylpyrazoles are described that have significant glucocorticoid and antiinflammatory activities. These agents competed with dexamethasone for the glucocorticoid receptor from the rat thymus, suppressed adrenal weight when administered orally to intact female rats, produced liver glycogen deposition and thymolysis when administered orally to adrenalectomized male rats, and reduced cotton granuloma formation when administered in the cotton pellet. In addition, in the latter model, no systemic activity (thymolysis or reduced body weight gain) was seen with doses up to 500 to 5000 times the dose which reduced granuloma formation. At least one compound was more potent than methylprednisolone in three of the four rat assay systems used. The compounds described are structurally different from conventional steroidal glucocorticoids but possessed potent glucocorticoid activities. However, they exhibited antiinflammatory activity without evidence of systemic activity when administered locally.

Inhibition of luteal phase progesterone levels in the rhesus monkey by epostane.

This study examined the effect of epostane, a new antifertility drug, on normal and hCG-stimulated progesterone production during the luteal phase of the menstrual cycle in rhesus monkeys. When administered once each day for five days, epostane inhibited normal luteal phase progesterone levels in a dose-related fashion. Epostane also reduced the elevated luteal phase progesterone levels of animals treated with hCG indicating that the drug acts directly on the corpus luteum. These data suggest that epostane interferes with corpus luteum function in a primate and that the drug would be effective as an interceptive agent during early pregnancy.

Win 32,729, a new, potent interceptive agent in rats and rhesus monkeys.

Win 32,729 [(2 alpha, 4 alpha, 5 alpha, 17 beta)-4,5-epoxy-17-hydroxy-4,17-dimethyl-3-oxoandrostane-2-carbonitrile] is an orally active interceptive agent in rats and rhesus monkeys (M mulatta). A single oral dose of 48 mg/kg terminated gestation when given on Day 10 of pregnancy. When given orally for up to 5 days to pregnant monkeys, it terminated pregnancy in 26 of 34 animals at a dose of 50 mg/monkey (ca 7 mg/kg), in 18 of 24 at a dose of 100 mg/monkey (ca 14 mg/kg) and in all 6 at 250 mg/monkey (ca 35 mg/kg). It did not inhibit ACTH-stimulated glucocorticoid production at 50 mg/monkey but did at a dose of 250 mg/monkey. This preferential gonadal inhibition was not evident in rodents. While in most cases five oral medications of 50-100 mg were required to terminate gestation in 50-day pregnant monkeys, a single subcutaneous medication with 250 mg was also effective, terminating pregnancy in 7 of 7 monkeys.

Endocrine profile of topterone, a topical antiandrogen, in three species of laboratory animals.

Topterone, 17 alpha-propyltestosterone, was administered parenterally or topically to rats, rabbits or hamsters to determine its endocrine profile. Systemic administration demonstrated that topterone was both antiandrogenic and progestational. Topical application failed to elicit a systemic antiandrogenic response at 1 g/kg/day and only a minimal progestational response was seen at 32 mg/kg/day. No other endocrine activities were detected.