Cholesterol metabolism in juvenile baboons. Influence of infant and juvenile diets.

The deferred effects of infant diets and the effects of juvenile diets on cholesterol metabolism were estimated in 83 baboons (Papio sp.) at 3.5 years of age. As infants, the animals were breast-fed or fed one of three formulas containing approximately 2, 30, or 60 mg/dl cholesterol. After weaning at 14 weeks of age, the animals were fed one of four juvenile diets high or low in cholesterol with saturated (P/S = 0.37) or unsaturated (P/S = 2.1) fats. Cholesterol absorption and cholesterol turnover were measured by fecal isotopic methods, and variables of cholesterol metabolism were estimated from a two-pool model. Among juvenile animals breast-fed during infancy, the percentage of cholesterol absorption was higher, while the fluxes of cholesterol from Pool A (QAA, QA, and QAB) and the cholesterol mass of Pool B were lower, compared to those fed formulas. The level of cholesterol in formulas fed during infancy did not influence cholesterol metabolism during the juvenile period. During the juvenile period, saturated fat significantly decreased the cholesterol production rate (QA) and increased the rate constants for cholesterol flux between Pool A and Pool B (KAB and KBA) compared to unsaturated fat. High cholesterol intake increased bile acid and neutral steroid excretion, cholesterol turnover rate, the mass of Pool A, and the rate constant KA and fluxes QA and QAA for removal of cholesterol from Pool A. However, KAB, t1/2 B (half-time of Pool B), and the percentage of cholesterol absorbed were decreased.(ABSTRACT TRUNCATED AT 250 WORDS)