STIMULATION OF HAMSTER ADIPOCYTE CYCLIC 3'-5'-NUCLEOTIDE PHOSPHODIESTERASE ACTIVITY BY IONOPHORE A23187 AND CALCIUM

1 January 1978

journal article
research article

Vol. 4 (4) , 299-309

Abstract

Incubation of hamster isolated fat cells with the ionophore A23187 and Ca for 20 min caused 30-40% increases in the cyclic 3'':5''-nucleotide phosphodiesterase (EC 3.1.4.17) activity of adipocyte homogenates when either 0.6 .mu.M cyclic AMP or 0.6 .mu.M cyclic GMP was the enzyme substrate. The stimulation of adipocyte cyclic AMP phosphodiesterase activity by A23187 and Ca was not antagonized by the adrenergic receptor blocking agents phentolamine and propranolol. The changes in enzyme activity produced by the ionophore and Ca were not associated with elevated intracellular cyclic AMP levels. A23187 and Ca acted to enhance adipocyte phosphodiesterase activity before, but not after, homogenization of the fat cells. The phosphodiesterase activity of hamster isolated fat cells may, at least in part, be regulated by fluctuations in intracellular Ca concentrations.

This publication has 1 reference indexed in Scilit:

Regulation of the high Km cyclic nucleotide phosphodiesterase of adrenal medulla by the endogenous calcium-dependent-protein activator
Biochemical and Biophysical Research Communications, 1976