Enhancement of cyclic AMP modulated salivary amylase secretion by protein kinase C activators.

The effect of protein kinase C activators on isoproterenol-induced amylase secretion were investigated in isolated rat parotid cells. Pretreatment with phorbol dibutyrate potentiated isoproterenol-induced amylase secretion. This effect of phorbol dibutyrate was mimicked by dioctanoylglycerol or carbachol. Phorbol dibutyrate also potentiated secretion evoked by the adenylate cyclase activator forskolin and by dibutyryl cAMP. Neither phorbol dibutyrate nor carbachol enhanced isoproterenol-induced cAMP accumulation. The present study reveals a coordinate interaction between cAMP and protein kinase C at a step in the secretory mechanism distal to cAMP generation.