AJP - Cell Physiology, Vol 271, Issue 3 C895-C904, Copyright © 1996 by American Physiological Society

ARTICLES

Modulation of phospholipase C pathway and level of Gq alpha/G11 alpha in rat myometrium during gestation

S. Lajat, Z. Tanfin, G. Guillon and S. Harbon
Centre National de la Recherche Scientifique Unite de Recherche Associee 1131, Universite Paris Sud, Orsay, France.

The regulation of the receptor-G protein-phospholipase C (PLC) cascade was investigated in rat myometrium at midgestation (day 12) and at term (day 21) comparatively to the estrogen-treated tissue (day 0). Carbachol-mediated generation of [3H]inositol phosphates was insensitive to pertussis toxin and was enhanced at days 12 and 21 two- and threefold, respectively, with no alteration of muscarinic sites (M3 subtype). A similar increase could be detected in the production of inositol 1,4,5-trisphosphate, indicating the stimulation of a PLC degrading phosphatidylinositol 4,5-bisphosphate. AlF4- also enhanced PLC activation during gestation, suggesting pregnancy-related regulations that bypass receptor activation. Immunoreactive G proteins, Gq alpha and G11 alpha, and PLC-beta 3 were detected in all myometrial preparations. The amount of PLC-beta 3 was similar in day 0 and day 21 myometrium, although decreasing by 75% at midgestation. Of significance was the increased amount of Gq alpha in day 12 and day 21 myometrium (3- and 2-fold, respectively) which coincided with the enhanced phosphoinositide breakdown. The upregulation of Gq alpha may contribute to the enhanced PLC activity during pregnancy and at term.

This article has been cited by other articles:

				P. Robin, I. Boulven, C. Desmyter, S. Harbon, and D. Leiber ET-1 stimulates ERK signaling pathway through sequential activation of PKC and Src in rat myometrial cells Am J Physiol Cell Physiol, July 1, 2002; 283(1): C251 - C260. [Abstract] [Full Text] [PDF]

				S. Dogan, T. A. White, D. A. Deshpande, M. P. Murtaugh, T. F. Walseth, and M. S. Kannan Estrogen Increases CD38 Gene Expression and Leads to Differential Regulation of Adenosine Diphosphate (ADP)-Ribosyl Cyclase and Cyclic ADP-Ribose Hydrolase Activities in Rat Myometrium Biol Reprod, March 1, 2002; 66(3): 596 - 602. [Abstract] [Full Text] [PDF]

				I. Boulven, B. Palmier, P. Robin, M. Vacher, S. Harbon, and D. Leiber Platelet-Derived Growth Factor Stimulates Phospholipase C-{gamma}1, Extracellular Signal-Regulated Kinase, and Arachidonic Acid Release in Rat Myometrial Cells: Contribution to Cyclic 3',5'-Adenosine Monophosphate Production and Effect on Cell Proliferation Biol Reprod, August 1, 2001; 65(2): 496 - 506. [Abstract] [Full Text] [PDF]

				S. Lajat, S. Harbon, and Z. Tanfin Carbachol-induced desensitization of PLC-beta pathway in rat myometrium: downregulation of Gqalpha /G11alpha Am J Physiol Cell Physiol, September 1, 1998; 275(3): C636 - C645. [Abstract] [Full Text] [PDF]