Effect of sucrose feeding upon intestinal and hepatic lipid synthesis

Abstract

Sucrose induces hypertriglyceridemia and increases intestinal triacylglycerol (TG), cholesterol (C), and very low density lipoprotein (VLDL) secretion in the rat. The effect of feeding a sucrose-enriched diet for 2 to 3 weeks upon rat intestinal and hepatic C, fatty acid (FA), and TG synthesis was measured and compared to animals fed chow and glucose-enriched diets. Sucrose did not alter intestinal lipid composition but increased hepatic weight and TG content. Rates of FA and C synthesis were estimated from the incorporation of 14C-2-acetate and of 3H2O into slices of proximal and distal intestine and of liver. Jejunal, but not ileal, C synthesis was stimulated by sucrose feeding, which resulted in elimination of the jejunoileal gradient for C synthesis found in rats fed control diets. There was no change in intestinal FA synthesis and 14C palmitate incorporation into intestinal TG was reduced. In the liver, no change in hepatic C synthesis was observed, but incorporation of 14C-2-acetate into total fatty acid was increased 3-fold and 3H2O incorporation over 2-fold by sucrose feeding. The incorporation of palmitate into hepatic TG was relatively enhanced and into hepatic phosphoglycerides depressed by sucrose. It is concluded that sucrose feeding stimulates jejunal C synthesis and transport in intestinal lipoproteins but that hepatic C synthesis may be modulated to prevent hypercholesterolemia. Since sucrose feeding docs not increase intestinal lipogenesis, circulating FA may be precursors for VLDL TG secreted in lymph.