Serum lipoproteins and atherosclerosis in animals.

The lipoproteins have been examined in more than 300 serum or plasma samples taken during life or at post mortem from a fairly wide range of mammals, birds and reptiles. The material, which was collected over a period of several years, was subjected to a limited range of lipid analyses, but all specimens were submitted to electrophoresis with paper or cellulose acetate membrane as supporting medium. The lipoprotein pattern in mammals appears to be basically similar to that in man, but there are wide variations in lipid concentrations; the highest levels being found in bears, seals and primates. High concentrations were also observed in many birds and a few reptiles, but the lipoprotein patterns in these vertebrates differ from those in mammals and are further greatly modified by oviparity. Semi-quantitative data on the degree of atherosclerosis were available on the animals that died. There was only a crude positive correlation between the intensity of the arterial disease and high serum beta-lipoprotein levels, and it was concluded that the latter are probably of only secondary importance in the development of spontaneous atherosclerosis in animals.