Influence of pregnancy on G-protein coupling to adenylate cyclase activation in guinea-pig myometrium

To assess the functional activity of the stimulatory GTP-binding protein G s we have measured adenylate cyclase activation by GTP, its non-hydrolysable analogue guanosine 5'-(β-γ-imido) triphosphate (Gpp(NH)p), fluoride, forskolin and manganese in a 50000g membrane fraction prepared from the myometrium of non-pregnant, mid-pregnant and latepregnant guinea-pigs