Hormone-induced redistribution of calcium-activated phospholipid-dependent protein kinase in pituitary gonadotrophs.
The distribution of calcium-activated, phospholipid-dependent protein kinase (protein kinase C) between cytosol and membrane fractions was analyzed in cultured pituitary gonadotrophs during treatment with gonadotropin-releasing hormone (GnRH). In pituitary cells purified by centrifugal elutriation, the extent of protein kinase C redistribution during GnRH stimulation was correlated with the enrichment of gonadotrophs. GnRH-stimulated release of luteinizing hormone (LH) from gonadotroph-enriched cells was accompanied by a rapid and dose-dependent decrease in cytosolic protein kinase C and by a corresponding increase in protein kinase C activity in the particulate fraction. Retinal directly inhibited the activity of cytosolic protein kinase C and also attenuated the release of LH from GnRH-stimulated gonadotrophs. These findings, and the ability of GnRH to cause rapid translocation of cytosolic protein kinase C to a membrane-associated form, suggest that hormonal activation of protein kinase C is an intermediate step in the stimulation of pituitary LH secretion by GnRH.
Hirota
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Hirota
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Aguilera
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D000818:Animals; D002852:Chromatography, Ion Exchange; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000201:enzymology*; D011493:Protein Kinase C; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012172:Retinaldehyde / Q000494:pharmacology; D013997:Time Factors; D014018:Tissue Distribution
D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D011494:Protein Kinases; D011493:Protein Kinase C; D012172:Retinaldehyde