Open AccessRegulation of protein kinase C by extracellular calcium in bovine parathyroid cells.
Author(s) -
Noritada Kobayashi,
J. Russell,
D Lettieri,
Louis M. Sherwood
Publication year - 1988
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.85.13.4857
Subject(s) - protein kinase c , diacylglycerol kinase , parathyroid hormone , extracellular , phospholipase c , protein kinase a , calcium , parathyroid chief cell , chemistry , medicine , endocrinology , cgmp dependent protein kinase , activator (genetics) , biology , biochemistry , kinase , mitogen activated protein kinase kinase , signal transduction , receptor
Regulation of protein kinase C in the parathyroid gland was investigated by testing the effects of phorbol ester, exogenous phospholipase C, and low and high calcium concentrations on enzyme activity. Treatment of bovine parathyroid cells with phorbol ester, which activates protein kinase C directly, and with phospholipase C, which produces diacylglycerol, an activator of protein kinase C, significantly stimulated protein kinase C activity. Both agents also enhanced the release of parathyroid hormone. Acute exposure of bovine parathyroid cells to low extracellular calcium (0.5 mM) caused a 5- to 6-fold increase in protein kinase C activity associated with the particulate fraction. In contrast, high extracellular calcium (1.75 mM and 2.5 mM) markedly decreased membrane protein kinase C activity. These data suggest that the effects of extracellular calcium on parathyroid hormone secretion are due, at least in part, to regulation of protein kinase C activity in the parathyroid-cell membrane.
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