Hormonal effects of a 5 alpha-reductase inhibitor (finasteride) on hormonal levels in normal men and in patients with benign prostatic hyperplasia.
Finasteride is a potent competitive 5 alpha-reductase inhibitor, active at a dose as low as 1 mg/day. After a single dose, the effects on 5 alpha-reductase last as long as 7 days. Both hepatic and target tissue 5 alpha-reductase are inhibited. Plasma testosterone and estradiol are unaffected and luteinizing hormone levels do not change. During chronic treatment with finasteride 5 mg/day, the effects on 5 alpha-reductase are maintained. Since the only significant effect of chronic finasteride therapy appears to be 5 alpha-reductase inhibition, and testosterone or estradiol levels are not affected, neither libido nor potency is lost. Testosterone is the active androgen at the muscular level; therefore, muscular catabolism is not expected.
Vermeulen
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Department of Endocrinology, University Hospital Ghent, Belgium.
Giagulli
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VA
De Schepper
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Buntinx
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D058891:5-alpha Reductase Inhibitors; D000728:Androgens / Q000097:blood; D000736:Androstenes / Q000008:administration & dosage / Q000627:therapeutic use*; D001378:Azasteroids / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004341:Drug Evaluation; D004958:Estradiol / Q000097:blood; D018120:Finasteride; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D011470:Prostatic Hyperplasia / Q000097:blood / Q000188:drug therapy*; D013739:Testosterone / Q000097:blood
D058891:5-alpha Reductase Inhibitors; D000728:Androgens; D000736:Androstenes; D001378:Azasteroids; D013739:Testosterone; D004958:Estradiol; D018120:Finasteride; D007986:Luteinizing Hormone