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PubMedDate not supplied

Drug interactions with fluconazole.

Fluconazole, a water-soluble bis-triazole antifungal agent that effectively penetrates the cerebrospinal fluid, is a highly selective inhibitor of the fungal cytochrome P450 system. In single-dose studies, coadministration of cimetidine and fluconazole (100 mg) resulted in an insignificant decrease in the absorption of fluconazole. The coadministration of rifampin and fluconazole (200 mg) decreased both the half-life and the area under the plasma concentration-time curve (AUC) of fluconazole. In multiple-dose studies, fluconazole (50 mg) did not significantly alter the pharmacokinetics of the two steroid components of an oral contraceptive. Coadministration of tolbutamide with fluconazole (100 mg) increased both the maximal plasma concentration and the AUC of tolbutamide without changing levels of blood glucose. The coadministration of cyclosporin A with a low dose of fluconazole (100 mg) was not associated with significant changes in the minimal and the maximal plasma concentrations of cyclosporin A. While higher doses of fluconazole (200 mg) did not affect endogenous steroids, coadministration resulted in changes in the pharmacodynamics of warfarin and the pharmacokinetics of phenytoin and cyclosporin A.

Adrenal Glands↗
PubMed1990

Vasectomy and the risk of prostate cancer.

An unexpected association between history of vasectomy and increased risk of prostate cancer emerged when multiple comparisons were carried out in data collected from 1976-1988 in a US hospital-based case-control study of many diseases and exposures. The association was assessed in detail in these data, in a comparison of 220 men with first episodes of prostate cancer with 571 noncancer controls and 960 cancer controls. The age-adjusted relative risk of prostate cancer was 5.3 (95% confidence interval 2.7-10) when noncancer controls were used and 3.5 (95 percent confidence interval 2.1-6.0) when cancer controls were used. The magnitude of the relative risk estimate appeared to be unrelated to the length of the interval after vasectomy. Allowance for several factors did not alter the estimates, but we did not have information on testosterone level or sexual activity, which may have been confounding factors. The association was stronger among men most likely to have been under more intensive medical surveillance; selective detection of asymptomatic cancer in such men would have led to an excess of cases. Further studies are needed to rule out chance, bias from medical surveillance, and uncontrolled confounding as explanations for the finding.

Adult↗
PubMed1990

Relationship between hormone profiles and the restoration of spermatogenesis in men treated with gossypol.

Gossypol acetic acid was administered orally to 35 male volunteers at a dose of 20 mg once a day for 52-70 days in the loading phase and twice a week for 22 months in the maintenance phase. Sperm counts and the serum concentrations of LH, FSH, prolactin, testosterone and oestradiol were monitored regularly during treatment and for a follow-up period of 12 months. At around 90 days after treatment, all treated participants approached or attained azoospermia and remained at this level throughout the maintenance phase. By the end of the follow-up phase, eight treated men were still azoospermic, while sperm counts in the other 27 men were restored to normal levels. The only hormone that changed significantly during and after the treatment was FSH. From the 6th month of the treatment to the end of the follow-up phase, serum concentrations of FSH in the eight participants that reached irreversible azoospermia were significantly higher than in the other 27 men or in controls. It is suggested that monitoring of FSH levels might be of diagnostic use for identifying those participants with irreversible azoospermia during gossypol treatment.

Administration, Oral↗
PubMed1991

Reversible azoospermia induced by an androgen-progestin combination regimen in Indonesian men.

The suppression of spermatogenesis by a combination of depot medroxyprogesterone acetate (DMPA) and testosterone enanthate (TE) was studied in Indonesian men. Twenty healthy, fertile volunteers were allocated randomly to either of two treatments each consisting of four intramuscular injections at monthly intervals. Group I (n = 10 men) received 100 mg DMPA plus 100 mg TE monthly while group II (n = 10 men) received 200 mg DMPA plus 250 mg TE monthly. Sperm concentration was suppressed markedly, with all men attaining azoospermia between the third and fourth month after the start of treatment. There was no significant difference in the suppression of spermatogenesis between the two dosage regimens. The median time to reaching azoospermia was 2.5 months from the onset of injections and the median time to recovery of sperm in the ejaculate was 2.0 months after cessation of treatment. Both steroid regimens were equally effective in suppressing LH, FSH and testosterone levels. Testosterone levels returned to baseline by the fourth post-treatment month while LH and FSH demonstrated significant rebound above baseline levels from 3 to 5 months after cessation of treatment. No serious clinical side effects were observed. Weight gain and increases in libido were reported during treatment by most volunteers. A transient decrease in libido was noted in 5/20 (25%) men between 1-2 months after cessation of injections, presumably due to the prolonged effects of DMPA relative to TE. These results indicate that uniform induction of reversible azoospermia with minimal side effects can be achieved in a non-Caucasian population.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1976

Vasectomy: a long-term study of its effects on testicular endocrine function in man.

Plasma testosterone, luteinizing hormone (L.H.) and follicle stimulating (F.S.H.) were measured before operation in 39 males, aged 26 to 53 years with 2 to 5 children, seeking vasectomy for contraceptive purposes. These measurements were repeated at 3 and 12 months after vasectomy. Levels of L.H. at 12 months were significantly higher than pre-vasectomy levels, suggesting some degree of decreased Leydig cell function. However, testosterone and F.S.H. levels were similar at the three sampling times. Continuing yearly measurements for at least 5 years are planned.

Adult↗
PubMedDate not supplied

Preliminary observations on steroid metabolism in isolated epithelum of guinea pig seminal vesicle.

The metabolism of nine radioactively labeled steroids in the epithelium of the seminal vesicle of the mature guinea pig has been studied. The rapid assimilation and metabolism of these steroids demostrate the very active biochemical nature of this tissue. Based on the use of several thin-layer chromatography systems and comparison with the locations of known standards, the following have been disclosed. Testosterone was rapidly converted to dihydrostestosterone and androstanediol. The latter was the major metablolite of dihydrotestosterone and of androsterone. Androstenedione was readily converted to androstanedione, testosterone, and dihydrostestosterone, although it formed little androstanediol. Dehydroepiandrosterone was converted to small amounts of androstenediol and androstanediol. Pregnenolone was rapidly converted to an unidentified highly polar compound only. Progesterone was converted to 5alpha-pregnane-3beta-ol-20-one and its 3alpha-isomer. Dehydroepiandrosterone and progesterone were also significantly converted to unidentified highly polar compounds. The major metabolites of 17-hydroxyprogesterone co-chromatographed with standard androstanediol, testosterone, and unidentified metabolite possessing intermediate chromatographic mobility. In addition, 17-hydroxyprogesterone was converted to small amounts of compounds possessing identical Rf values as standard androstenedione and dihydrostestosterone. The identification of the products of 17-hydroxyprogesterone metabolism and their physiologic significance must await critical evaluation. Because of its homogeneity, isolated epithelium of guinea pig seminal vesicle shows promise as a tissue preparation for use in future studies that might elucidate the role(s) of individual androgens in secretory tissues of the male accessory sex organs. Our demonstration of extensive steroid interconversions in this tissue is a logical prerequisite to such studies.

Androgens↗
PubMed1975

The pituitary-testicular response to luteinising hormone releasing hormone administration to normal men.

The response of the pituitary and testis in normal men to the injection of LH-RH has been studied using single intravenous doses of either 25 mug or 100 mug. Serum LH levels rose with both doses but significant elevation of plasma testosterone was evident only following 100 mug of LH-RH. Though testosterone levels were elevated within 60 minutes, peak responses occurred from 4-12 hours post-injection. The rise in serum FSH levels was small or absent at 25 mug but was clearly present following 100 mug LH-RH, in general rising more slowly than LH levels but persisting for a longer period.

Adult↗
PubMed1975

Anti-inflammatory steroids, lysosomal stabilization and parachor.

Parachor is an additive constitutive property of a molecule and is related to the molar volume and the surface tension. The parachor of a steroid can be calculated from its constituent atoms and bonds. The parachor of a biologically active molecule is related to the ability of that molecule to permeate hydrophobic regions of cells, especially cellular membranes. An examination of the parachor values of a large number of steroids shows that these values are correlated with a number of different biological activities, from independent sources. The ability of steroids to release lysosomal enzymes from isolated lysosomes in vitro is inversely related to the parachor of the steroid. A similar relationship holds for the release of lysosomal beta-glucoronidase (EC 3.2.1.31) from isolated lysosomes of rat preputial gland following in vivo administration of steroids. The relative anti-inflammatory potencies of steroids by several assay methods are directly proportional to their parachors. The relative ability of corticosteroids to uncouple oxidative phosphorylation and to swell isolated mitochondria in vitro show a direct proportionality with the steroidal parachor. The percutaneous absorptions of steroids show good correlation with parachors, stratum corneum-water partition coefficients and amylcaproate-water partition coefficients; but not with hexadecane-water partition coefficients. The application of parachor as a structure-activity correlation parameter in drug design is likely to yield useful information. The advantages and limitations of the calculated parachor method are discussed.

Androgens↗
PubMed1975

Changes in gonadotropin secretion following complete or hemicastration in the adult rat.

The effect of sham castration, hemicastration or complete castration on gonadotropin and testosterone secretion was studied in adult male rats. Untreated control rats were autopsied 1, 10, 20, 30 and 40 days following assignment to treatment groups. Sham-castrated controls were autopsied 1, 2 and 3 days after surgery. Complete and hemicastrates were autopsied 1, 2, 3, 10, 20, 30 and 40 days after surgery. Serum levels of both FSH and LH were elevated by 24 h postcastration and the levels of both gonadotropins continued to rise throughout the course of the experiment. Serum levels of LH rose following hemicastration and remained above control values through day 30. Serum FSH levels were not significantly affected by hemicastration. Compensatory testicular hypertrophy was not observed in hemicastrated rats.

Animals↗
PubMed1976

Effect of a new LH-RH analogue (D-Ser(TBU)6-EA10-LH-RH) on gonadotrophin and gonadal steroid secretion in men.

The effect of a new analogue of the gonadotrophin-releasing hormone LH-RH, D-Ser(TBU)6-EA10-LH-RH, on the secretion of LH, FSH, as well as testosterone, oestradiol, HGH, prolactin, TSH, and cortisol was studied in normal men. The same subjects were injected intravenously in 4-day intervals with 1.0, 2.5, 5.0, and 10.0 mug of this substance. A significant LH but no FSH release was seen after doses of 1.0 and 2.5 mug LH-RH analogue, while after 5.0 and 10.0 mug dose-dependent increases of LH and imposed elevations of FSH were observed. Peak levels of LH were reached after 30 min, those of FSH after intravenous injection after 120 min. LH and FSH remained elevated for 8-10 h. LH peak levels after 5 mug of LH-RH analogue were comparable to those seen after injection of 100 mug of the decapeptide LH-RH. Following the release of LH and FSH after doses of 5.0 and 10.0 mug LH-RH analogue, there was a late stimulating effect in testosterone and oestradiol secretion. HGH, TSH, prolactin, and cortisol were not influenced by the LH-RH analogue.

Adult↗