Ecto-ATPase mRNA is regulated by FSH in Sertoli cells

A putative messenger RNA (mRNA) sequence, designated C8, that was up-regula ted in Sertoli cells prepared from hypophysectomized rats treated with test osterone, was isolated from a Sertoli cell complementary DNA (cDNA) library . The coding region of C8 exhibited 99% identity with rat brain ecto-ATPase and expressed a 60-kilodalton protein following in vitro transcription/tra nslation. Transfection of COS7 cells with C8 cDNA resulted in a marked incr ease in Ca2+- and Mg2+-dependent ATPase activity in both whole cells and ce ll homogenates, which is consistent with localization of this enzyme in the plasma membrane. C8 ecto-ATPase steady state mRNA levels were increased wi thin 6 hours and for 3 days by follicle-stimulating hormone (FSH) in Sertol i cells but not in peritubular cells. in contrast, dibutyryl-cyclic adenosi ne monophosphate (cAMP) increased ecto-ATPase in both Sertoli and peritubul ar cells. Testosterone had no significant effect under these conditions. Th ese data indicate that ecto-ATPase mRNA is positively regulated by FSH in S ertoli cells and by cAMP in both Sertoli and peritubular cells. This enzyme may play a role in the control of extracellular signaling by ATP, adenosin e, or both in the cells of the seminiferous epithelium.