Insulin sensitizes b-agonist and forskolin-stimulated lipolysis to
inhibition by 2'5'-dideoxyadenosine.
Gokmen-Polar, Yesim, Elizabeth C. Coronel, Suleiman W. Bahouth, and
John N. Fain.
The University of Tennessee, Memphis, Departments of Biochemistry
and Pharmacology, 858 Madison Avenue, Memphis, TN 38163
APStracts 2:0312C, 1995.
In isolated rat adipocytes incubated in the absence of insulin, 2'5'
-dideoxyadenosine blocked the increase in total cyclic AMP
accumulation due to [beta]1 or [beta]3 catecholamine agonists and
forskolin without affecting their stimulation of lipolysis. The
inhibition of cyclic AMP accumulation by 2'5'-dideoxyadenosine was
not reflected in the total cytosolic cyclic AMP dependent protein
kinase A activity, suggesting that the inhibition of cyclic AMP
occurred in cellular compartments distinct from those involved in the
regulation of bulk protein kinase A activity. However, there was a
good correlation between effects of lipolytic agents on cytosolic
protein kinase A activity in fat cell extracts and lipolysis.
Furthermore, it was possible to see an inhibition of the increase due
to [beta]-agonists in cyclic AMP accumulation, protein kinase A
activity and lipolysis by 2'5'-dideoxyadenosine in the presence of
insulin. These data suggest that the readily measurable accumulation
of cyclic AMP seen with catecholamines in the absence of insulin is
in a compartment separate from that involved in protein kinase A
activation.
Received 27 April 1995; accepted in final form 15 August 1995.
APS Manuscript Number C233-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 15 September 1995.