Reversal of the desensitized state of pig ovarian follicular human choriogonadotropin-sensitive adenylylcyclase by guanosine 5'-O-(2-thiodiphosphate)

J Biol Chem. 1992 Nov 5;267(31):22183-9.

Abstract

We investigated the stability of the desensitized state of the human choriogonadotropin (hCG)-sensitive adenylylcyclase of the pig ovarian follicle. A 20,000 x g membrane preparation of pig follicular membranes was incubated under conditions which resulted in the hormone-induced desensitization of the hCG-responsive adenylylcyclase. The desensitized state was maintained upon subsequent incubation of the membranes with GTP, GDP, GMP, ATP, ADP, AMP, CTP, UTP, adenyl-5'-yl imidodiphosphate (AMP-P(NH)P), and adenyl (beta, gamma-methylene)-diphosphonate (AMP-P(CH2)P); however, the desensitized state was reverted to a fully active state upon incubation with guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) and guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S). The reversal effect of GDP beta S on hCG-responsive adenylylcyclase activity was time- and temperature-dependent, and showed a selectivity for GDP beta S over adenosine 5'-O-(2-thiodiphosphate) (ADP beta S) (half-maximal effective dose of 12 microM versus 260 microM, respectively). GDP beta S had no effect on the binding affinity or apparent number of luteinizing hormone (LH)/CG receptors or on the dissociation rate of 125I-hCG from the receptor. GDP beta S promoted an hCG- and time-dependent release of guanine nucleotides from the membranes. A model is proposed which accounts for the unique characteristics of LH/CG-sensitive adenylylcyclase desensitization and subsequent reactivation by GDP beta S.

MeSH terms

  • Adenylyl Cyclases / metabolism*
  • Animals
  • Cell Membrane / metabolism
  • Chorionic Gonadotropin / pharmacology*
  • Female
  • GTP-Binding Proteins / physiology
  • Guanine Nucleotides / metabolism
  • Guanosine Diphosphate / analogs & derivatives*
  • Guanosine Diphosphate / pharmacology
  • Guanosine Triphosphate / pharmacology
  • Nucleotides / pharmacology
  • Ovarian Follicle / enzymology*
  • Receptors, LH / physiology
  • Swine
  • Temperature
  • Thionucleotides / pharmacology*

Substances

  • Chorionic Gonadotropin
  • Guanine Nucleotides
  • Nucleotides
  • Receptors, LH
  • Thionucleotides
  • Guanosine Diphosphate
  • guanosine 5'-O-(2-thiodiphosphate)
  • Guanosine Triphosphate
  • GTP-Binding Proteins
  • Adenylyl Cyclases