Synergistic functions of phorbol ester and calcium in serotonin release from human platelets

Effects of growth factors on cytosolic free calcium concentration and DNA synthesis in cultured rat aortic smooth muscle cells.

“…Therefore, lacking of an inhibitory effect of nifedipine on PDGF-induced increase in DNA synthesis might be explained by the hypothesis that an activation of protein kinase C caused by PDGF is enough to promote DNA synthesis in SMCs. This idea is further supported by the evidence that activation of protein kinase C by synthetic diacylglyceride or phorbol ester elicites the biological response in human platelets without accompanying the calcium mobilization Yamanishi et al 1983 ;Nishizuka 1984). Moreover, Rink et al (1983) have directly confirmed that neither diacylglycerol nor phorbol ester evokes the increase in cytosolic free calcium concentration in human platelets.…”

The phorbol ester‐induced extracellular Ca2+‐independent release of LH is dependent on estradiol and de novo protein synthesis

“…Subsequent studies indicated an indirect role for CAMP [3], suggesting that the nucleotide interacts with some other intracellular mediator(s) which directly regulates this component of LH secretion. Interestingly, diacylglycerols (DAGs) and phorbol esters which can activate protein kinase C (PKC) without increases of intracellular Ca2+ [4,5], stimulated LH secretion in the absence of extracellular Ca2+ [6,7]. These observations suggest PKC as a possible direct mediator of the GnRHstimulated extracellular Ca2+-independent release of LH.…”

Inhibition of stimulus‐dependent epidermal growth factor receptor and transforming growth factor‐α mRNA accumulation by the protein kinase C inhibitor staurosporine

“…Protein kinase C is a CaZ+/phospholipiddependent enzyme that is activated directly by diacylglycerol generated during receptor-mediated inositol phospholipid turnover [1,2] or by tumor promoters such as 12-O-tetradecanoylphorbol-13-acetate (TPA) [3][4][5]. Activation of protein kinase C is known to have a variety of effects on cells (for review, see [6]) and is thought to play important roles in both signal transduction and cellular proliferation.…”