Amphibian oocyte: a model of a possible regulatory mechanism for prostaglandin E2 and prostaglandin F synthesis

in Journal of Endocrinology
Authors:
A Gobbetti
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M Zerani
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Abstract

To clarify the possible mechanisms regulating prostaglandin E2 (PGE2) and prostaglandin F (PGF) synthesis, the effects of gonadotropin-releasing hormone (GnRH) and substance P (SP) on the release of these two prostaglandins were studied in the oocytes of the crested newt, Triturus carnifex. Full-grown oocytes of T. carnifex, freed from follicular cells, were incubated in the presence of GnRH or SP and of the inhibitors of several enzymes involved in the release of arachidonic acid (AA) and in the conversion of AA into PGE2 and PGF. In parallel, the same experiments were performed on oocytes with membrane phospholipids labelled with [3H] AA. In addition, the PGE2-9-ketoreductase activity was evaluated through the conversion of [3H]PGE2 into [3H]PGF. The results showed that GnRH and SP could regulate prostaglandin synthesis through the activation of phospholipase C and diacylglycerol lipase, and through the modulation of PGE2-9-ketoreductase in the oocytes of T. carnifex. In particular, GnRH enhances the activty of PGE2-9-ketoreductase with a consequent increase in PGF, while SP inhibits the enzyme which leads to an increase in PGE2. A similar mechanism could also be hypothesized for other vertebrate species.

Journal of Endocrinology (1995) 145, 235–241

 

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