Cholesterol turnover and tissue distribution in the guinea pig in response to dietary cholesterol

Cholesterol turnover and tissue cholesterol distribution were studied in guinea pigs fed either a control diet or one containing 0.1% cholesterol. Dietary cholesterol caused a significant increase in the cholesterol concentration in liver, red blood cells and small intestine, but not in plasma. Most of the increase in total body cholesterol could be accounted for as an increase in liver esterified cholesterol content. Feeding the 0.1% cholesterol-containing diet did not significantly change either the absorption of an oral dose of tracer cholesterol or the endogenous cholesterol synthesis rate. Steady state cholesterol input-output rate and total traced mass of cholesterol were significantly greater, and mean transit time was significantly longer in the animals fed the cholesterol containing diet. These data suggest that the maintenance of cholesterol homeostasis in the nonhypercholesterolemic cholesterol-fed guinea pig depends on liver accumulation of esterified cholesterol as well as on increased output of cholesterol.