Regulation of protein kinase C by extracellular calcium in bovine parathyroid cells.
AUTOR(ES)
Kobayashi, N
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=280535Documentos Relacionados
- Protein kinase C modulates hormone secretion regulated by extracellular polycations in bovine parathyroid cells.
- Regulation of parathyroid hormone release and cytosolic calcium by extracellular calcium in dispersed and cultured bovine and pathological human parathyroid cells.
- Cytosolic calcium homeostasis in bovine parathyroid cells and its modulation by protein kinase C.
- Unusual calcium-activated potassium channels of bovine parathyroid cells.
- Direct regulation by calcium of cytoplasmic messenger ribonucleic acid coding for pre-proparathyroid hormone in isolated bovine parathyroid cells.
