PT  - JOURNAL ARTICLE
AU  - M. J. PETERSON
AU  - C. C. HILLMAN
AU  - J. ASHMORE
TI  - Nicotinic Acid: Studies on the Mechanism of Its Antilipolytic Action
DP  - 1968 Jan 01
TA  - Molecular Pharmacology
PG  - 1--9
VI  - 4
IP  - 1
4099  - http://molpharm.aspetjournals.org/content/4/1/1.short
4100  - http://molpharm.aspetjournals.org/content/4/1/1.full
SO  - Mol Pharmacol1968 Jan 01; 4
AB  - Nicotinic acid in vitro is known to depress basal lipolytic rates in adipose tissue and also to inhibit the action of a number of agents which stimulate adipose tissue lipolysis. Three possible mechanisms by which nicotinic acid could exert this antilipolytic effect have been examined. The rat epididymal fat pad was used as an adipose tissue source. In vitro nicotinic acid was found to have no effect on fat pad phosphodiesterase activity. Similarly, no direct effect of this drug on lipase activity could be demonstrated. Nicotinic acid in vitro was observed to inhibit, by about 50%, the increased lipolytic rates induced in isolated fat pad sections with theophylline. This inhibitory action, however, was antagonized by the further in vitro addition of the β-adrenergic blocking agent, nethalide, (pronethalol). Also, this antagonism appeared to be a direct one. It is suggested from these results that nicotinic acid does not exert its antilipolytic action by either increasing the degradation of cyclic 3',5'-AMP or by inhibiting directly the activity of lipase. It would appear, however, that nicotinic acid acts at a site that is either identical with the receptor for nethalide or is closely associated to it. Thus, it seems possible that nicotinic acid may exert its antilipolytic action by depressing the production of cyclic 3',5'-AMP. ACKNOWLEDGMENT These studies were supported in paid by Public Health Service grants AM 07211 and GM 953.