Allopregnanolone and pregnanolone are produced by the human corpus luteum

Using a dispersed human luteal cell culture model, progesterone, allopregnanolone, and pregnanolone release following treatment by incremental doses of human chorionic gonadotrophin (hCG) were evaluated. Corpus luteum tissues, obtained from 48 healthy women scheduled for benign surgery, were grouped according to luteal age and tissue concentration of allopregnanolone and pregnanolone was determined. The mRNA expression of 5 alpha-, and 5 beta-reductase and 3 alpha-HSOR mRNA expressions were evaluated in corpora lutea from the late luteal phase. Allopregnanolone concentrations in corpus luteum tissue were consistently about three- to four-fold higher than pregnanolone levels. Allopregnanolone tissue concentrations significantly decreased between early- and late-luteal phase, p < 0.05. When exposed to hCG, progesterone output from freshly obtained human corpora lutea cells was two- three-fold increased compared to control levels. With 0.1 U/ml hCG a two-fold increase in allopregnanolone levels were noted, whereas pregnanolone levels were increased by approximately 40%. Furthermore, the mRNA of 5 alpha-, 5 beta-reductase and 3 alpha-HSOR mRNA were all expressed in human corpus luteum. In conclusion, the neurosteroids allopregnanolone and pregnanolone are produced in the human corpus luteum and their release is stimulated by trophic hormone. (c) 2005 Elsevier Ireland Ltd. All rights reserved.