Changes in meal pattern and endogenous feeding related substances following mazindol administration.

In order to ascertain direct central anorectic actions of mazindol (MZD), subtle changes in meal patterns and endogenous feeding related chemical substances were examined in rats following intra-third ventricle injection of 0.03 mumole MZD. In ad lib feeding, MZD decreased meal size and prolonged postprandial intermeal interval during a 4 hr period starting 2 hr after injection. The magnitude of anorectic actions of MZD was depressed by hunger. Although the action of MZD is short in duration, long duration anorexia was achieved by chronic infusion for 8 days. Infusion of MZD starting at 5:50 p.m. decreased plasma insulin, leaving glucose and glucagon unaffected, although no change in plasma glucose or insulin was observed following injection at 11:30 a.m. These findings, together with other reports, can be explained by MZD's direct effects on the hypothalamic hunger and satiation centers.