Pregnenolone synthesis in immature rat Sertoli cells

It has been reported that testicular Sertoli cells can be induced to synthe size the steroidogenic acute regulatory (StAR) protein. StAR mediates the r ate-limiting step of steroidogenesis, which is the transfer of cholesterol to the inner mitochondrial membrane. Since Sertoli cells are thought to be unable to utilize cholesterol for the synthesis of steroids the role of StA R in these cells was questioned. In the present studies we have corroborate d the induction of StAR protein in immature cultured Sertoli cells in respo nse to either trophic hormone or cAMP analog stimulation. Further, we have shown that long term stimulation of Sertoli cells with cAMP analog results in the induction of P450sec enzyme and increased pregnenolone production. I n this manner, the Sertoli cell may resemble its ovarian homolog, the granu losa cell, more closely than previously thought with regards to its steroid ogenic capacity. Thus, StAR may play the same role in Sertoli cells as it d oes in other steroidogenic tissues. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.