Primate Biliary Physiology

Abstract

Long and medium chain triglyceride supplements, a fat-free diet, and fasting were randomly allocated to rhesus monkeys with chronic exteriorized enterohepatic circulations and the effects on biliary lipid and bile salt metabolism were compared during steady state conditions to respective prediet control periods. Safflower oil and triolein supplements increased bile flow, biliary lipid secretion, bile salt synthesis, and pool size without altering the relative composition of bile. Tricaprylin decreased bile salt synthesis, pool size, and secretion in bile. The relative proportion of biliary cholesterol was decreased by tricaprylin because cholesterol secretion into bile was decreased, while the number of daily circulations of the bile salt pool was increased. The fat-free diet and fasting also decreased bile salt synthesis, pool size, and secretion. While the fat-free diet had no other significant effects, fasting decreased bile flow and the secretion of all biliary lipids, but increased the relative proportion of cholesterol in bile. In addition, fasting decreased the number of daily circulations of the bile salt pool. Total caloric deprivation altered all parameters of bile salt metabolism adversely and came closest of all experiments in producing bile saturated with cholesterol. Conversely, tricaprylin was the only diet which improved the cholesterol-holding capacity of bile.