Sphingosine Derivatives, Calmodulin Inhibitors, and TMB-8: Inhibitors of Adenylate Cyclase Activity in Rat Luteal Membranes

Prostaglandin F2α (PGF) plays a major role in the initiation of luteal regression in many mammalian species (1). In luteal preparations incubated in vitro, PGF inhibited cAMP accumulation (2, 3). When adenylate cyclase activity was measured in luteal membranes, PGF added directly to the reaction mixture had no effect; however, exposure to PGF of intact corpora lutea in vitro or in vivo resulted in impaired adenylate cyclase activity in subsequently prepared luteal membranes (4).