STEROIDOGENIC ENZYME-ACTIVITIES IN RAT POLYCYSTIC OVARIES

Ovaries containing multiple follicular cysts occur in a variety of ano vulatory conditions. A macrocystic condition occurs spontaneously in r ats following a single injection of estradiol valerate. The ovaries ar e small, and exhibit scant stromal tissue, few healthy follicles, and numerous large cystic and precystic follicles. We have also generated a microcystic condition by means of subcutaneous estradiol-containing silastic implants. These ovaries are large, and exhibit a stroma of hy pertrophied lipid-filled cells, and numerous small cysts encircled by hypertrophied thecal cells. The macrocystic condition is associated wi th a uniformly attenuated plasma luteinizing hormone (LH) pattern, whe reas large LH episodes characterize the microcystic condition. The mar ked dissimilarities between these two methods suggest that there may b e corresponding differences in ovarian steroidogenic activity. We have measured the activity of enzymes involved in progestin and androgen b iosynthesis in the two types of multicystic ovaries before and after L H - human chorionic gonadotropin (hCG) stimulation. Control ovaries we re obtained at late proestrus from age-matched cycling animals. Radiom etric enzyme assays for 3beta-hydroxysteroid dehydrogenase (3beta-HSD) , 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD), C-17, C-20-lyase (lyase), and aromatase were conducted on die microsomal fraction of o varian homogenates. 3beta-HSD activity was reduced by > 50% in both ty pes of cystic ovaries compared with controls. There was a slight eleva tion in the 3beta-HSD activity of macrocystic ovaries in response to h CG. 20alpha-HSD activity was similar in controls and macrocystic ovari es but significantly lower (< 20% of control) in the microcystic ovari es. Lyase and aromatase activities were undetectable in cystic ovaries . Although these results are consistent with the morphology and plasma LH patterns characterizing the macrocystic condition, the microcystic ovary presents an unexpected paradox. These results underscore the co mplexity and multidimensional nature of cystic ovarian disease.