The present study examined the effect of protein kinase C (PKC) on cyclic AMP metabolism in PC18 cells, a recently developed model of the adrenal medullary chromaffin cell. Activation of PKC with phorbol 12-myristate 13-acetate (PMA) significantly potentiated cAMP accumulation in response to the adenosine analog N6-R-phenyl-isopropyl adenosine (PIA) and to forskolin. The degree of potentiation of both PIA and forskolin-stimulated cAMP levels was significantly reduced but not completely eliminated when cells were incubated in the presence of the cAMP-phosphodiesterase (cAMP-PDE) inhibitor Ro20-1724. PMA pretreatment had no detectable effect on either cytosolic or membrane-bound low Km cAMP-PDE activity, but did significantly potentiate PIA-dependent adenylate cyclase activity. We conclude that the potentiation of agonist-dependent cAMP accumulation by PKC in intact PC18 cells is due to both an enhancement of cAMP biosynthetic capacity, as well as a suppression of cAMP catabolic activity.
|Number of pages||4|
|State||Published - Jan 31 1994|
Bibliographical noteFunding Information:
The authors thank Dr. A.W. Tank for providing the PC18 cells, and Mr. Kevin Krause for assistance with figure preparation. These studies were supported by the American Heart Association, Kentucky Affiliate, and by a University of Kentucky Medical Center Research Grant #93 648.
- Adenylate cyclase
- Adrenal medulla
- Phorbol ester
ASJC Scopus subject areas
- Neuroscience (all)