Compositional changes in plasma high-density lipoprotein particles in marginally zinc-deficient male rats

This study investigated the effect of zinc status on the lipid and apolipoprotein composition of high-density lipoproteins (HDL) in adult male rats fed a semipurified diet containing a marginal level (2.8 mg/kg) of Zn as compared with the pair-fed and ad libitum-fed controls given an adequate level (30.8 mg/kg) of Zn for 7-10 wk. Compositional and chromatographic analysis of HDL fraction showed that Zn deficiency significantly lowered the total amount of circulating HDL particles with no effect on the concentrations of total protein, triglyceride, phospholipid, and cholesterol. The ratios of free: esterified cholesterol remained the same for the three groups. Electrophoretic analysis of the apolipoprotein profile showed marked decreases in the relative contents of apolipoproteins E and C and an increase in apolipoprotein (apo) A-I with no significant change in apo A-VI. No apparent morphologic aberrations of HDL particles were observed. Such changes may significantly influence the transport and metabolism of cholesterol and may provide an explanation for altered cholesterol homeostasis in Zn deficiency.