The effect of protein kinases on desensitization of the porcine follicular membrane luteinizing hormone/chorionic gonadotropin-sensitive adenylyl cyclase

Marilyn L.G. Lamm, Richard C. Ekstrom, Evelyn T. Maizels, Rajsree M. Rajagopalan, Mary Hunzicker-Dunn*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Because the acute homologous phase of desensitization of the LH/CG-sensitive adenylyl cyclase in porcine follicles is readily demonstrated in a cell-free membrane preparation, it follows that any enzyme(s) required to achieve desensitization must be present in the membranes and must be activated upon LH/CG receptor activation. The purpose of the following studies was to determine whether modulation of endogenous membrane protein kinases, with activators or inhibitors, or addition of exogenous protein kinases affected desensitization of the LH/CG-sensitive adenylyl cyclase. The effects of these potential modulators were evaluated in both the presence and absence of ligand (hCG)-stimulated receptor activation. To this end, membranes were incubated in the presence or absence of hCG (stage 1) and then assayed for adenylyl cyclase activity in the presence or absence of hCG (stage 2). The results showed that although porcine follicular membranes rich in LH/CG-sensitive adenylyl cyclase activity also exhibited cAMP-dependent [protein kinase-A (PKA)], cGMP-dependent (PKG), lipid-dependent (PKC), Ca2+/calmodulin, and casein kinase-I and -II activities, only full hCG-stimulated adenylyl cyclase activity (measured with BSA in stage 1 and hCG in stage 2) was reduced upon addition of exogenous PKC (to the stage 1 incubation). hCG-dependent desensitization of cAMP synthesis (measured with hCG in stages 1 and 2) was unaffected by activators or inhibitors of endogenous PKA, PKC, or PKG, by an inhibitor of casein kinases and kinases in the beta-adrenergic receptor kinase family, or by the addition of exogenous active PKA, PKC, or rhodopsin kinase to the stage 1 incubation. These results suggest that the acute homologous phase of hCG-dependent desensitization of adenylyl cyclase activity in follicular membranes is not regulated by PKA, PKC, PKG, or messenger-independent heparin-sensitive protein kinases.

Original languageEnglish (US)
Pages (from-to)1745-1754
Number of pages10
JournalEndocrinology
Volume134
Issue number4
DOIs
StatePublished - Apr 1994

ASJC Scopus subject areas

  • Endocrinology

Fingerprint Dive into the research topics of 'The effect of protein kinases on desensitization of the porcine follicular membrane luteinizing hormone/chorionic gonadotropin-sensitive adenylyl cyclase'. Together they form a unique fingerprint.

Cite this