Gonadotropin-Releasing Hormone-Stimulated Phosphoinositide Hydrolysis in the Anterior Pituitary
作者:
Maria A. Sortino,
William S. Evans,
Carmela Speciale,
Michael O. Thorner,
Umberto Scapagnini,
Robert M. MacLeod,
Pier L. Canonico,
期刊:
Neuroendocrinology
(Karger Available online 1988)
卷期:
Volume 48,
issue 5
页码: 544-550
ISSN:0028-3835
年代: 1988
DOI:10.1159/000125061
出版商: S. Karger AG
关键词: GnRH;Phosphoinositides;Protein kinase C;Cyclic AMP;Cyclic GMP;PMA;Gonadotroph;LH;Diacylglycerol analogs
数据来源: Karger
摘要:
Gonadotropin-releasing hormone (GnRH) produces a rapid and concentration-dependent hydrolysis of polyphosphoinositides in rat anterior pituitary cells in culture. Evaluation of the action of the decapeptide by measurement of [3H]-inositol phosphates and of prelabeled phosphoinositides demonstrated an effect on phosphatidylinositol-4,5-bis-phosphate and phosphatidylinositol-4-phosphate earlier than on phosphatidylinositol. The receptor antagonist [D-pGlul, D-Phe2, D-Trp3,6]-luteinizing hormone-releasing hormone blocked the effect of GnRH on [3H]-inositol phosphate production. Protein kinase C activators attenuated GnRH-induced phosphoinositide hydrolysis, while neither cyclic AMP analogs nor cyclic GMP analogs were effective. These results indicate that phosphoinositide hydrolysis represents an important postreceptor transducing mechanism for GnRH action at the gonadotroph and that protein kinase C (but not cyclic nucleotides) may exert a negative feedback control on GnRH receptor-coupling mechanisms.
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