Expression of 11-hydroxysteroid dehydrogenase (11HSD) proteins in luteinizing human granulosa–lutein cells

In a range of tissues, cortisol is inter-converted with cortisone by 11-hydroxysteroid dehydrogenase (11HSD). To date, two isoforms of 11HSD have been cloned. Previous studies have shown that human granulosa cells express type 2 11HSD mRNA during the follicular phase of the ovarian cycle, switching to type 1 11HSD mRNA expression as luteinization occurs. However, it is not known whether protein expression, and 11HSD enzyme activities reflect this reported pattern of mRNA expression. Hence, the aims of the current study were to investigate the expression and activities of 11HSD pro-teins in luteinizing human granulosa–lutein (hGL) cells. Luteinizing hGL cells were cultured for up to 3 days with enzyme activities (11-dehydrogenase (11DH) and 11-ketosteroid reductase (11 KSR)) and protein expression (type 1 and type 2 11HSD) assessed on each day of culture. In Western blots, an immunopurified type 1 11HSD antibody recognized a band of 38 kDa in hGL cells and in human embryonic kidney (HEK) cells stably transfected with human type 1 11HSD. The type 2 11HSD antibody recognized a band of 48 kDa in HEK cells transfected with human type 2 11HSD cDNA but the type 2 protein was not expressed in hGL cells throughout the 3 days of culture. While the expression of type 1 11HSD protein increased progressively by 2·7-fold over 3 days as hGL cells luteinized, both 11DH and reductase activities declined (by 52·9 % and 34·2%; P,0·05) over this same period. Changes in enzyme expression and activity were unaffected by the suppression of ovarian steroid synthesis. Journal of Endocrinology (2003) 178, 127–13