The effects of zinc sulphate on hypercholesterolaemia induced by cholesterol-choleate in rats

The effects of zinc sulphate on cholesterol-choleate-induced hypercholesterolaemia were studied in rats. Zinc sulphate (20 or 40 mg/kg, p.o. once daily for 5 days) administration, which raised serum zinc levels, significantly increased bile acid secretion and lowered high-density lipoprotein-cholesterol (HDL-C) levels in the serum. Cholesterol-choleate, given by the same route and schedule, markedly elevated serum total cholesterol level, but decreased serum HDL-C concentration. Bile acid in serum and in bile was also increased, but these changes were inhibited by zinc sulphate pretreatment. Zinc sulphate also worsened the decrease in HDL-C and slightly prolonged the elevation in total cholesterol produced by cholesterol-choleate administration. It is concluded that the moderate increase in serum total cholesterol level by zinc sulphate could be due to inhibition of hepatic metabolism of cholesterol to bile acid. The specific action of zinc ions on HDL-C metabolism is discussed.