Progesterone metabolism in human endometrial stromal and gland cells in culture

Metabolism of progesterone by human endometrium has been described, but the rapidity and extent of progesterone metabolism is incompletely documented in cellular fractions of normal endometrium. Therefore, we evaluated proges terone metabolism in separated stromal and gland cells in culture obtained from normal human endometrium by thin-layer chromatography. We rind that in both cell types, the most abundant metabolite is 3 beta-hydroxy-5 alpha-pr egnan-20-one (70%), followed by 5 alpha-pregnane-3,20-dione (15%), and 3 al pha-hydroxy-5 alpha-pregnan-20-one (10%). A small amount is metabolized to 5 alpha-pregnane-3 alpha/3 beta,20 alpha-diols and to 3 beta,6 alpha-dihydr oxy-5 alpha-pregnan-20-one. The metabolism of progesterone in cultured endo metrial cells occurs rapidly; 70% of progesterone is metabolised in 8 h, an d 90% by 24 h. We conclude that when in vitro experiments are conducted uti lizing progesterone treatment, the rapidity and the extent of the metabolis m of this steroid should be taken into account. (C) 1999 Elsevier Science I nc. All rights reserved.