Chorionic Gonadotropin-Sensitive Adenylate Cyclase in Human Term Placenta

Abstract

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.