Send to

Choose Destination
J Clin Endocrinol Metab. 1999 Jul;84(7):2414-8.

5alpha-reductase activity in women with polycystic ovary syndrome.

Author information

Department of Obstetrics and Gynecology, Second Clinic of Surgical Gynecology, University School of Medicine, Lublin, Poland.


The recent demonstration of high concentrations of 5alpha-androstane-3,17-dione in the follicular fluid of polycystic ovaries suggests a potential role for 5alpha-reduced androgens in the etiology of polycystic ovary syndrome (PCOS). The purpose of the present study was to determine whether there is increased 5alpha-reductase activity or messenger ribonucleic acid (mRNA) expression in polycystic ovaries. 5alpha-Reductase 1 and 5alpha-reductase 2 mRNAs were measured in thecal (TC) and granulosa (GC) cells from individual follicles of 18 women with PCOS and 26 regularly cycling control women. Both 5alpha-reductase 1 and 2 mRNA expression was higher in GC than in TC, and 5alpha-reductase 2 mRNA levels were approximately 3-fold higher than 5alpha-reductase 1 mRNA. 5alpha-Reductase 1 and 2 mRNA expression were similar in GC from PCOS and control women, but 5alpha-reductase mRNA was decreased in TC from PCOS follicles. In control women, 5alpha-reductase 2 mRNA was highest in GC from 3- to 5-mm follicles and decreased to undetectable levels in GC from 7-mm follicles. A similar pattern of expression was present in GC from PCOS follicles, but detectable levels of 5alpha-reductase 2 mRNA were present in GC from 7-mm follicles. 5alpha-Reductase activity was measured in whole follicles by measuring the conversion of radiolabeled testosterone to dihydrotestosterone. Kinetic analysis of total 5alpha-reductase activity at physiological pH revealed a Km of 1.46 micromol/L and a maximal velocity of 0.31 nmol/min x mg protein, indicating predominantly type 1 activity. The total 5alpha-reductase activity was approximately 4-fold higher in PCOS follicles than in control follicles. These data demonstrate elevated 5alpha-reductase activity in polycystic ovaries and support the hypothesis that 5alpha-reduced androgens may play a role in the pathogenesis of PCOS.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center