Influence of doxazosin on lipid transport in rats and hamsters.

A variety of nutritional conditions were investigated to identify those most responsive in terms of selective alpha 1-adrenergic inhibition (alpha 1-inhibition) on the serum lipid concentrations in rats and hamsters. In rats fasted for 24 h and then refed a lipogenic diet for the same period, serum triglycerides were markedly elevated. Inclusion of the selective alpha 1-adrenergic inhibitor (alpha 1-inhibitor) doxazosin in the diet decreased the intensity of this response. Serum cholesterol was not appreciably altered by the drug in these animals. Although dietary doxazosin did not affect serum lipids in rats fed chow ad libitum, in chow-fed hamsters (which have much higher serum lipid levels than rats) consumption of the drug for 4 days substantially decreased serum levels of both triglyceride and cholesterol. Very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol were all decreased by doxazosin. It is suggested that selective alpha 1-inhibition influences lipoprotein metabolism at several sites, including both formation and removal processes. The hamster may be especially useful in studies designed to define these sites and the underlying mechanisms involved.