Comparative effects of dietary fatty acids and triglycerides on lymph lipids in the rat

The influence of fatty acids and corresponding triglycerides on the intestinal absorption of cholesterol has been studied in lymph-fistula rats. Butyric and lauric acids, given with bile salt and cholesterol as the free acids or the triglycerides, had little effect on total lymph lipids or on absorption of exogenous cholesterol. Palmitic acid gave a marked increase in lymph lipids which was due entirely to a rise in neutral fat, and a simultaneous depression of cholesterol absorption. The administration of stearic, oleic or linoleic acids produced large increases in the lymph levels of neutral fat and phospholipids. Oleic acid was most efficient, with linoleic and stearic acids somewhat less effective, in promoting cholesterol absorption. The increases in total lymph lipids after tristearin or triolein were less marked than with the free fatty acids, while in the case of trilinolein, total lipids, neutral fat, and phospholipid levels were comparable to the levels after linoleic acid. Of the triglycerides studied, only trilinolein caused a significant elevation of total lymph cholesterol.

Quantitative effects of bile salt and fatty acid on cholesterol absorption in the rat

The influence of various molar proportions of oleic acid and sodium taurocholate on the absorption of cholesterol and upon the lipid partition of thoracic duct lymph has been studied. In bile fistula rats a marked reduction of all lipid fractions of lymph was evident. The administration of oleic acid, taurocholate and cholesterol, singly or in various combinations to these animal preparations failed to elevate the lipid levels to those found in the fasting control animals having a normal bile circulation. The inclusion of up to 430 mg of taurocholate in an intragastric emulsion containing 50 mg of cholesterol and an excess of fatty acid failed to produce significant absorption of cholesterol, emphasizing the importance of the continuous circulation of the bile constituents for the absorption of cholesterol. In lymph fistula animals a molar relationship of oleic acid, taurocholate and cholesterol of 8:4:1 was found to be most effective for lipid and cholesterol absorption from the intestine and phospholipid production by the intestinal mucosa. Several levels of cholesterol greater than 50 mg were administered in emulsions in which the contents of fatty acid and bile salt were optimum for cholesterol absorption at the 50-mg level. No increase in absorption occurred either in absolute amounts or in percentage of the administered sterol. The results of these studies indicate the necessity of fatty acid, bile salt and cholesterol, present at the same time and in the proper molar amounts, for optimal transfer of fatty acid and cholesterol in the rat.

Sorbic acid as a selective agent in cucumber fermentations. II. Effect of sorbic acid on the yeast and lactic acid fermentations in brined cucumbers

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Dietary fat and hypercholesteremia in the Cebus monkey. II. Esterification and disappearance of cholesterol-4-C14

A series of studies of cholesterol metabolism in the Cebus monkey were carried out in an attempt to understand the mechanisms responsible for the great differences in serum cholesterol levels when different dietary fats were used. Three groups of monkeys, one fed diets including 45 per cent of calories as corn oil, a second corn oil plus cholesterol (0.1 gm./100 calories), and a third lard plus cholesterol for 5 months (mean serum cholesterol values were 237, 268, and 601 mg. per cent, respectively) were injected with emulsions of cholesterol-4-C(14). The mean biological half-lives for the disappearance of serum radiocholesterol were 8.8, 8.4, and 6.6 days respectively. Esterification of radiocholesterol as measured by equilibration of specific activities of serum-free cholesterol and total cholesterol was delayed in the monkeys fed lard plus cholesterol. When cholesterol-4-C-(14)-stearate was given intravenously to a series of monkeys, an erratic non-exponential biological decay curve resulted. Specific activity for free serum cholesterol was greater than that for total cholesterol within 1 hour after the injection. After 7 months on experimental diets including corn oil with added cholesterol and lard with added cholesterol the levels of lipides in most tissues were not different for the two dietary groups, nor were they appreciably elevated above previous control figures for monkeys not fed cholesterol. Total lipide levels in the adrenals of monkeys fed corn oil were twice those of monkeys fed lard. Monkeys were fasted before and after intragastric administration of cholesterol-4-C(14) in small formula meals including various fats and fatty acids. The disappearance of total cholesterol from the serum consisted of a rapid followed by a slow exponential function. The type of fat and fatty acid appeared to influence the rate of disappearance of radiocholesterol. There was a broad range of apparent activity of the different fats and fatty acids in promoting cholesterol absorption.