Molecular Pharmacology, Vol 2, 237-247, Copyright © 1966 by the American Society for Pharmacology and Experimental Therapeutics

Effect of Drugs on the Lipolytic Action of Hormones in Isolated Fat Cells

¹ National Institute of Arthritis and Metabolic Diseases, National Institutes of Health, Bethesda, Maryland, and Division of Biological and Medical Sciences, Brown University, Providence, Rhode Island

The effect of various drugs on the lipolytic action of growth hormone plus dexamethasone was compared with that on the action of ACTH and epinephrine in isolated fat cells from starved rats. Phenoxybenzamine reduced the acceleration of lipolysis by growth hormone plus dexamethasone but had no significant effect on that of either ACTH or epinephrine. Butoxamine inhibited the effect of growth hormone plus dexamethasone and of ACTH on lipolysis.

dl--hydroxy-N-tert-butyl-2,4-dichlorophenethylamine (DCB) stimulated lipolysis and did not prevent the acceleration of lipolysis by growth hormone and dexamethasone. There was no lipolytic effect of epinephrine and ACTH in the presence of DCB. Propranolol, which is a beta adrenergic blocking agent with little sympathomimetic activity, completely blocked the lipolytic effect of epinephrine. Propranolol did not inhibit the lipolytic action of either ACTH or growth hormone plus dexamethasone.

Nicotinic acid blocked the lipolytic effect of growth hormone plus dexamethasone, and theophylline potentiated their lipolytic action. Actinomycin D blocked the lipolytic effect of growth hormone and dexamethasone, but not of epinephrine.

Note:
ACKNOWLEDGMENTS The authors would like to thank Professor R. E. Parks, Jr., for his comments (during the preparation of this manuscript and Miss Nancy Davis for her technical assistance in some of the experiments.