Disparate effects of prazosin and propranolol on lipid metabolism in a rat model.

Rats treated with high (3.0 mg/kg) or low (0.3 mg/kg) doses of prazosin had significantly lower (p less than 0.01) plasma triglyceride levels and a lower triglyceride secretion rate than control rats. Propranolol had no effect on triglyceride levels when compared with controls. There was a significant elevation of plasma cholesterol concentrations in propranolol-treated rats when compared with animals given prazosin. The ratio of high-density lipoprotein cholesterol to total cholesterol was significantly greater in prazosin-treated rats than in controls and propranolol-treated rats. Free fatty acid levels were significantly lower in the prazosin-treated group, a finding that may explain reduced very low-density lipoprotein and triglyceride secretion. These data demonstrate that the disparate effects on lipid metabolism of the alpha- and beta-receptor antagonists studied, previously shown to occur in hypertensive man, can be duplicated in the normal rat. This animal model may prove useful for the study of adrenergic mechanisms in lipid metabolism.