The distribution of serum high density lipoprotein subfractions in non-human primates

The ultracentrifugal flotation patterns in 1.2 g/ml solvent and ultracentrifugal gradient distribution of high density lipoproteins (HDL) from the primates-human, apes and monkeys-were determined, with emphasis on the gorilla species of apes and rhesus monkeys. Diets for non-human primates were commercial chow, which is low in cholesterol. Molecular weights and protein, cholesterol, phospholipid and triglyceride compositions of various density fractions were determined on human, gorilla and rhesus HDL. The HDL₂/HDL₃ ratio was determined from the two peaks observed upon flotation in high salt in the analytical ultracentrifuge. The HDL₂ of all three species of apes-gorillas (Gorilla gorilla), chimpanzees (Pan troglodytes) and orangutans (Pongo pygmaeus)—was always greater than HDL₃, while that of all six species of Old World monkeys-Rhesus (Macaca mulatta), sooty mangabeys (Cercocebus atys), cynomolgus (Macaca fascicularis), stumptails, (Macaca arctoides) patas (Erythrocebus patas) and African greens (Cercopithecus aethiops)—was less. In addition, the HDL₃ concentration in five gorillas was about 15 mg/dl as cholesterol while the HDL₂ concentration was 92 mg/dl, much lower and higher, respectively, than humans. HDL₂ of gorillas was similar in density and molecular weight to that of humans. The distribution of densities in gorilla HDL was predominantly in HDL₂, while rhesus HDL usually, but not always, was unimodal, having a density distribution similar in heterogeneity to human HDL₃, but somewhat less dense (peaking at 1.109 vs 1.129 g/ml). The molecular weight of rhesus HDL was about the same as human HDL₃ in all three density subfractions and at the peak density. Likewise, the chemical compositions were similar for the subfractions 1.10–1.125 and>1.125 g/ml for rhesus HDL and human HDL₃. Consequently most but not all chow-fed rhesus HDL was very similar to human HDL₃, but lighter in density. A preliminary report of this study was given at the American Society for Biological Chemists Meeting in New Oreleans in April 1982.