In vitro inactivation of gonadotropin receptors, a membrane-associated action?

Under in vitro conditions the time-dependent inactivation process of LH/HCG receptors is nearly identical in ovarian and testicular homogenates but different in gonadal membrane preparations. In the ovarian membranes the loss of binding sites during the first preincubation time is faster than in testicular membranes, especially in membranes of luteinized rat ovaries. Compared with the homogenates, however, the receptor-inactivation in the membranes is generally delayed. The inhibitory effect of metabolic agents on receptor inactivation indicates that membrane-associated actions are involved in this process.