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Signal pathways mediating oxytocin stimulation of prostaglandin synthesis in select target cells
Author(s) -
Soloff Melvyn S.,
Jeng YowJiun,
Copland John A.,
Strakova Zuzana,
Hoare Sarasija
Publication year - 2000
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1111/j.1469-445x.2000.tb00007.x
Subject(s) - microbiology and biotechnology , intracellular , oxytocin , prostaglandin , biology , second messenger system , cytosol , signal transduction , biochemistry , endocrinology , enzyme
A major action of oxytocin is to stimulate prostaglandin production in reproductive tissues. The two major enzyme systems involved are cytosolic phospholipase A 2 (cPLA 2 ), which catalyses the formation of arachidonic acid from membrane glycerophospholipids, and prostaglandin endoperoxide‐H synthases‐1 and ‐2, which allow conversion of arachidonic acid to prostaglandins. During gestation, the concentrations of all three enzymes rise in the rabbit amnion. Agonists, including oxytocin, increase cPLA 2 activity, in part, by elevating intracellular Ca 2+ concentration, which causes cPLA 2 to be translocated from the cytosol to intracellular membrane binding sites. Cytosolic PLA 2 is then activated by a mitogen‐activated protein kinase (MAPK)‐dependent step. Our studies have elucidated signal pathways involved in oxytocin‐stimulated prostaglandin output in both rabbit amnion cells and Chinese hamster ovary cells stably transfected with the rat oxytocin receptor. The two cell types are alike with respect to oxytocin‐stimulated intracellular Ca 2+ transients, mediation via G q , and the specific MAPK that catalyses the phosphorylation of cPLA 2 . However, they differ with respect to the mechanisms of upregulation of key enzymes involved in prostaglandin E 2 synthesis. These findings illustrate the tiers of complementary mechanisms involved in oxytocin stimulation of prostaglandin E 2 , and the extent of the diversity in the cellular signalling pathways involved.