Effect of Lipotropic Substances on Phosphatide Turnover in Liver

EFFECT OF LIPOTROPIC SUBSTANCES ON PHOSPHATIDE TURNOVER IN LIVER 

The striking effect of lecithin upon the liver of a depancreatized dog (maintained with insulin) was found to be due to its content of choline, which reduces the fat content of the liver of depancreatized rats as well as of rats fed a diet rich in fat. The fact that the rate of formation of new phosphatide molecules in the liver is accelerated by the administration of choline, was established by Perlman and Chaikoff (139). Rats were fed for three days on a diet high in fat and low in protein on the fourth day, half of each group were given 3 mg. of labeled phosphate and 30 mg. of choline chloride, simultaneously. The remaining half was pven the labeled phosphate only. All animals were killed 4 hours after the administration of P. While the phosphatides in the livers of the controls were found to contain 2.23% of the P administered, the liver phosphatides of the choline-treated rats contained 2.92% (see also 137). Increased formation of labeled phosphatides was found to appear approximately 1 hour after choline ingestion, and its effect had disappeared about 10 to 12 hours later. 

As distinct from choline, which promotes the formation of new phosphatide molecules in liver, cholesterol was found to have an opposite effect. 

While the control diet consisted of 5 g. of unsalted butter to which was added 0.015 ml. of a standardized cod liver oil and 0.1 ml. of a vitamin B concentrate, the cholesterol diet contained the above constituents and added amoimts of cholesterol varying from 250-400 mg. All rats were injected with labeled phosphate 26 hours after first receiving these diets, and their livers were removed 4 hours later. The liver phosphatides of the control rats contained, on the average, 2.9% of the P administered, while the liver phosphatides of the rats fed cholesterol contained 2.3%. 

In another set of experiments, choline and cholesterol were fed simultaneously. 

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E. Effect of Lipotropic Substances on Phosphatide Turnover in Liver. 138... 

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