Greater importance of Ca2+-calmodulin in maintenance of ang II-and K+-mediated aldosterone secretion: Lesser role of protein kinase C

Arunabha Ganguly, Shirley Chiou, Naomi S. Fineberg, John S. Davis

Research output: Contribution to journalArticle

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Abstract

In this study we have investigated various components of the stimulus-secretion coupling process leading to aldosterone secretion from the calf adrenal glomerulosa cells as evoked by angiotensin II (AII) and potassium (K+). The roles of Ca2+, calmodulin and protein kinase C in the sustained phase rather than initiation of aldosterone secretion were of special interest. Our investigations revealed that the reduction of extracellular Ca2+ by EGTA or interruption of Ca2+ influx by nitrendipine at various time points after stimulation with either AII or K+ markedly compromised aldosterone secretion. Calmodulin inhibitors, calmidazolium and W-7 reduced aldosterone secretion profoundly. Agonists of protein kinase C, phorbol ester or diacylglycerol analogues failed to stimulate aldosterone secretion while the protein kinase C inhibitor, H-7, only partially inhibited aldosterone secretion at a concentration which completely inhibited protein kinase C activity. Calmodulin inhibitors produced significantly greater inhibition of aldosterone secretion than inhibitors of protein kinase C.

Original languageEnglish (US)
Pages (from-to)254-261
Number of pages8
JournalBiochemical and Biophysical Research Communications
Volume182
Issue number1
DOIs
StatePublished - Jan 15 1992

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ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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