Tumour‐promoting phorbol esters inhibit agonist‐induced phosphatidate formation and Ca2+flux in human platelets

Autor:	MacIntyre, D.E., McNicol, A., Drummond, A.H.
Zdroj:	FEBS Letters; January 1985, Vol. 180 Issue: 2 p160-164, 5p
Abstrakt:	Tumour‐promoting phorbol esters (phorbol‐12‐myristate‐13‐acetate, PMA; phorbol‐12,13‐dibutyrate, PDBu) but not 4β‐phorbol, activate protein kinase C. Using human platelets pre‐labelled with quin2 or 32PO4we examined the effects of these compounds on human platelet cytosolic free Ca2+([Ca2+]j) and on [32]phosphatidic acid ([32P]PtdOH). PMA and PDBu, but not 4β‐phorbol inhibited thrombin‐, PAF‐ and vasopressin‐induced elevation of [Ca2+], and [2+P]PtdOH formation. It is suggested that protein kinase C may act to terminate the transduction processes that link receptor occupancy to cellular activation.
Databáze:	Supplemental Index
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