D.B. Zilversmit

The Synthesis of Phospholipids in Human Atheromatous Lesions

Femoral arteries, abdominal aortas, one renal artery, and one coronary artery removed from patients injected with P32 phosphate showed in most instances an active incorporation of the label into the phospholipids of intima and adventitia. A comparison of the specific activities of arterial plaque and plasma phospholipids suggests that the excess arterial phospholipids are originally derived from synthesis by the arterial wall, or at least undergo continuous renewal in situ.

The effect of cholesterol on the turnover of lecithin, cephalin and sphingomyelin in the rabbit☆

Abstract The turnover of lecithin, sphingomyelin, and non-choline-containing phospholipides in the aorta, plasma, and liver of control and cholesterolfed rabbits was studied with the aid of radioactive phosphorus. In the cholesterol-fed animals, aortic lecithin and sphingomyelin, as well as plasma cephalins, lecithin, and sphingomyelin showed highly significant increases in concentration and rate of synthesis. The fact that in the greater proportion of the cholesterol-fed animals the specific activities of individual aortic phosphatides exceeded those of the corresponding lipides in plasma is presented as further evidence that the aortic phospholipides are synthesized in the aorta itself rather than derived from the plasma by deposition.

The origin of bile lecithin and the use of bile to determine plasma lecithin turnover rates

Abstract Lecithin was extracted from hepatic bile of dogs injected with inorganic phosphate P 32 . The purified chloroform-methanol extract was found to contain all the phosphatide phosphorus and to be free of P 32 contaminants. Comparison of liver, plasma, and bile phosphatide specific activities demonstrated that bile contains only lecithin, which is produced by the liver from the same precursor as is plasma lecithin. The collection of plasma and bile lecithin from chronic bile fistula dogs injected with P 32 furnished a method for calculating the turnover rate of plasma lecithin.

Fate of Intravenously Administered Glycerol.

Summary Intravenously administered glycerol rapidly disappears from the bloodstream. Single injections of 6 g glycerol did not produce excessive urinary excretion of glycerol but 12 g led to excretion of one-third the dose. Daily infusions of large doses of glycerol produced marked polyuria and in some animals led to tremors and convulsions. These disturbances were not caused by accumulation of glycerol in the blood.

Role of the liver and intestine in the turnover of plasma phosphatides in the rat

Abstract The synthesis of plasma phosphatides in the fasting rat was reduced to insignificant amounts by removal of the liver. In cream-fed rats, the intestine contributed appreciable amounts of phosphatide to the plasma. The removal of phosphatides from the plasma continued, although at a somewhat slower rate, in the absence of the liver and intestine. The role of the liver and intestine in the metabolism of plasma phosphatides in different species of animals is discussed.

The fate of intravenously administered egg yolk phospholipides in dogs.

Abstract 1. 1. P32-labeled egg yolk phospholipides disappeared from the blood-stream of dogs with an initial half-time of 6–8 hr., which is similar to that for native plasma phospholipides. 2. 2. Most of the phospholipides remaining from 6 to 24 hr. after injection of the egg yolk were found in the liver, with relatively small amounts in lung or spleen. 3. 3. In the 24-hr. period studied there appeared evidence of continuous breakdown of the egg yolk phospholipides.