Chorionic gonadotropin sensitive adenylate cyclase in human term placenta.

Adenylate cyclase activity in a homogenate and washed particles of human term placenta proceeded maximally in the presence of 17 mM Mg2+ and 7.0 mM F− ion. The requirements for Mg2+ can be substituted by Mn2+, but not by other metal ions. Adenylate cyclase activity was not stimulated in vitro in a homogenate preparation by the addition of hCG. However, using a minced placental preparation, hCG stimulated the incorporation of 14C-adenine into 14C-cyclic AMP. The stimulatory effect of hCG on placental cyclic AMP formation was concentration dependent and specific. These experiments suggest that hCG may have a cyclic AMP-mediated role in placental function.