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Effect of finasteride on human testicular steroidogenesis.

We studied the testicular function and some androgen-mediated events in 22 males (16-30 years of age) with male pattern baldness that was treated with finasteride (10 mg once daily) for 2 years. Patients were evaluated every 3 months. Prostatic volume was determined in six subjects by endorectal ultrasound scans. Serum gonadotropin, prostate-specific antigen (PSA), and sex hormone levels were determined basally and periodically during the treatment period. Fourteen subjects underwent gonadal stimulation with human chorionic gonadotropin (hCG), and the gonadotropin response to gonadotropin releasing hormone (GnRH) was determined in eight subjects, prior to and after 2 years of therapy. Finasteride treatment resulted in an improvement in the male pattern baldness and prostatic shrinkage that was associated with an increase in serum testosterone levels (17.2 +/- 2.5 vs. 26.3 +/- 1.7 nmol/L) and a decrease in dihydrotestosterone (DHT) levels (1.45 +/- 0.41 vs. 0.38 +/- 0.10 nmol/L), causing a marked increase in that testosterone/DHT ratio. A significant increase in the serum levels of androstenedione (3.67 +/- 0.49 vs. 7.05 +/- 0.70 nmol/L) and estradiol (132 +/- 44 vs. 187 +/- 26 pmol/L) was also noted, whereas androstanediol glucoronide (33.3 +/- 6.4 vs. 10.7 +/- 4.5 pmol) and PSA (1.6 +/- 0.6 vs. 0.4 +/- 0.1 ng/ml) were significantly decreased. No changes in basal or stimulated levels of gonadotropin were observed. There was a significant increase in the testosterone response to hCG during finasteride therapy (delta: 16.7 vs. 35.5 nmol/L) that could be explained, at least in part, by the reduction of testosterone metabolism resulting from the blockage induced by finasteride. The decrease in the androstenedione to testosterone and estrone to estradiol ratios observed after hCG treatment, however, strongly suggests increased activity of the 17-ketosteroid reductase enzyme and an improvement of the testicular capacity for testosterone production.

Adult↗

PubMedDate not supplied

Diaryl chalcogenides as selective inhibitors of thioredoxin reductase and potential antitumor agents.

Thioredoxin reductase is a selenocysteine containing flavoenzyme that catalyzes the NADPH dependent reduction of the redox protein thioredoxin. Thioredoxin is over-expressed by a number of human tumors. Experimental studies have shown that thioredoxin is responsible for the growth and transformed phenotype of some human cancer cells. Thus, thioredoxin reductase presents an attractive target for anticancer drug development to regulate the activity of the thioredoxin system. We have examined a series of 12 organoselenium compounds and 16 organotellurium compounds, mostly of the diaryl chalcogenide type, as inhibitors of human thioredoxin reductase and have investigated the cytotoxicity and antitumor activity of some of the compounds. The organoselenium compound Ebselen was found to be a competitive inhibitor of human thioredoxin reductase (Ki 2.8 microM), while a number of organotellurium compounds were found to be noncompetitive inhibitors (Kis 2.3 to 35.2 microM). Human glutathione reductase was not appreciably inhibited by any of the compounds, except for one dinitro organotellurium compound that caused inhibition with an IC50 of 0.5 microM and an over 20-fold selectivity compared to thioredoxin reductase. The compounds inhibited the growth of human cancer cells in culture with IC50s as low as 2 microM Some organotellurium compounds when administered daily by intraperitoneal injection to mice caused up to 50% inhibition of the growth of MCF-7 human breast cancer xenografts but the relative insolubility of the compounds was a limiting factor in their use.

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