Cork R J, Taylor M, Varnold R L, Smith L D, Robinson K R
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
Dev Biol. 1990 Oct;141(2):447-50. doi: 10.1016/0012-1606(90)90399-4.
GTP-gamma-S inhibits progesterone-induced maturation of Xenopus laevis oocytes and induces a rise in their cAMP levels. GTP-gamma-S does not inhibit MPF-induced maturation. Although GTP-gamma-S prevents the progesterone-induced increases in protein synthesis and phosphorylation, it has no effect on the basal rates of either. GTP-gamma-S also prevents the initial DAG drop induced by progesterone. GDP-beta-S effects are ambiguous, but it seems not to affect progesterone-induced maturation. These results suggest that although G-proteins are associated with the pathways affected by progesterone, the effects of progesterone are not mediated by a typical receptor/G-protein/effector interaction.
