EFFECT OF SELENIUM DEFICIENCY ON HEPATIC LIPID AND LIPOPROTEIN METABOLISM IN THE RAT

Since experimental Se deficiency results in a significant increase in plasma cholesterol concentration the present investigation was underta ken to assess further the influence of this deficiency on the expressi on of proteins involved in hepatic lipid metabolism. Se deficiency was induced by feeding weanling male Wistar rats on a deficient diet for 6 weeks. Hypercholesterolaemia associated with Se deficiency was relat ed to increased 3-hydroxy-3-methylglutaryl-coA (HMG-CoA) reductase (EC 1.1.1.34) activity in liver microsomes as compared with control anima ls. Hepatic lipoprotein receptor levels (LDL-receptor and HDL-binding proteins, HB1 and HB2) were not significantly affected by Se deficienc y, as assessed by immunoblotting. Plasma triacylglycerol concentration s tended to decrease in Se-deficient rats in concert with their reduce d post-Triton secretion. There was no significant effect of Se deficie ncy on the hepatic synthesis of apolipoproteins. These results point t o the need for further investigations into the mechanism related to th e increased activity of HMG-CoA reductase and the enhanced choiesterog enesis in the liver of Se-deficient rats likely to result from this.