Cholesterol and apolipoprotein distribution in plasma high-density-lipoprotein subclasses from zinc-deficient rats

Effect of zinc deficiency on the composition of plasma high-density-lipoprotein (HDL) subclasses was investigated in adult male rats (ZD) fed a diet containing 2.8 micrograms of Zn/g as compared with pair-fed (PF) and ad libitum-fed (CT) controls given 30.8 micrograms of Zn/g. Three HDL subclasses were isolated by heparin-affinity chromatography: HDL containing no apo E (HDL-E0), HDL with a moderate amount of apo E (HDL-E1), and HDL highly enriched in apo E (HDL-E2). The plasma levels of total HDL cholesterol and protein were markedly decreased in ZD. The decreases were due primarily to a significant decline in circulating HDL-E0 particles. The percent content of free cholesterol in HDL-E2 was increased in ZD compared with PF and CT. Zn deficiency decreased the plasma concentrations of apo A-I and apo C of HDL-E0 and total apo E associated with HDL-E1 and HDL-E2. The mechanisms for such changes await further investigation.