Effects of portacaval shunt on the cholesterol metabolism of genetically hypercholesterolemic rats ("Rico' strain).

The effects of portacaval anastomosis on the biodynamics of cholesterol in male adult rats of a genetically hypercholesterolemic strain (Rico) were studied using an isotopic equilibrium method. Animals received a sucrose-rich semipurified diet. In both hypercholesterolemic rats and controls, portacaval anastomosis decreased plasma cholesterol levels (27%), liver weight (35-43%) and total cholesterol content in liver and body pools. Rico rats were characterized by (1) a high input rate of newly synthesized cholesterol (internal secretion) (25.3 +/- 1.9 vs. 16.2 +/- 1.5 mg/day/rat in controls) related to increased hepatic cholesterogenesis, and (2) a high rate of cholesterol transformation into bile acids, while other parameters remained unchanged. Portacaval anastomosis decreased the internal secretion of cholesterol in Rico rats (20.1 +/- 2.0 mg/day/rat). Since the activity of the gut for cholesterol synthesis as shown by the fecal external secretion (cholesterol biosynthesized by the gut and directly eliminated in the gut and feces) was not modified, it is assumed that the reduction of internal secretion induced by portacaval anastomosis results from decreased hepatic cholesterogenesis.