Microinjected GTP-gamma-S inhibits progesterone-induced maturation of Xenopus oocytes |
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Authors: | R J Cork M Taylor R L Varnold L D Smith K R Robinson |
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Institution: | Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907. |
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Abstract: | 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. |
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