The effect of carbon tetrachloride poisoning on serum lipoproteins associated with atherosclerosis.

Carbon tetralchloride was injected into normnal rabbits and the levels of Sf 3-12, 12-20, alnd(20-40 lasses of lipoproteins were determined during the course of these injections. A marked increase in concentration of these three classes of lipoproteins occurred during the administration of carl)on tetra(hloride. After the cessation of this drug, the lipoproteins of largest Sf rate returned to normal first with those of lower Sf rate returning to normal levels in the order of decreasing Sf rates. Rabbits fed cholesterol were also injected with carbon tetralchloridle, and their lipoproteins continued to inmrease after cessation of this (drug. UILITRACENTRIFUGAL studies reported by Gofman and co-workers1 have revealed certain lipoproteins in the serum of rabbits and humans that are associated with the development of athero-.Sclerosis. Studies now in progress in this laboratory are directed toward elucidation of the factors responsible for the maintenance of the blood levels of the various lipoproteins. The probable role of the liver as an important organ involved in lipid metabolism prompted the study of the effect of impaired liver function on the levels of the lipoproteins in the blood. Carbon tetrachloride (C04) has long been known for its ability to produce a fatty liver and eventual hepatic cirrhosis.2 This agent has also been shown to be capable of producing an elevation in the total serum cholesterol levels in the rabbit.3 It, was felt, therefore, that the nature of lipid transport (in terms of the lipo-proteins involved) in animals treated with carbon tetrachloride might provide information as to certain factors, at least, involved in maintaining blood lipoprotein levels. 29 the presence of lipoproteins characterized by flotation rates in the range of Sf 3-12.* A few apparently normal rabbits shows, in addition , very low concentrations of lipoproteins with flotation rates Sf 12-20. During cholesterol feeding experiments rabbits in general show increases in the Sf 3-12 components, followed by the development of very high levels of other lipoproteins of flotation rates greater than 12 Sf units and up to flotation rates over 100 Sf units. In general the molecules of higher Sf rates develop following a prior increase in those of the lower Sf rates, for example, appreciable concentrations of Sf 20-40 lipoproteins appear only after significant levels of Sf 12-20 components have appeared. These previous studies have indicated that the extent of atherosclero-sis developing in such rabbits parallels the level of the Sf 12-30 classt of lipoproteins. These …