Species differences in blood serum reserves for cholesterol solubilization.
The capacity of male human, rat, and guinea pig sera to solubilize cholesterol was measured by in vitro equilibration. Evaporation, adsorption by filter paper and/or cholesterol, and protein denaturation were controlled by measuring serum protein and albumin along with cholesterol contents. The uptake of cholesterol for the above groups was 23.1 +/- 1.2, 18.9 +/- 1.8, and 10.7 +/- 0.8 mg/100 ml, respectively. The percentage increases over initial serum cholesterol were 11.9 +/- 0.9, 18.7 +/- 2.0, and 35.1 +/- 2.7%, respectively. The uptake of cholesterol by serum per se without involvement of either releasing or target tissues appears to be an irreversible and protective solubility phenomenon; no cholesterol plates were deposited upon the undissolved solute or precipitated on addition of triglyceride to cholesterol-saturated serum. The omnivorous human and rat had a greater absolute reserve for solubilizing cholesterol, but the herbivorous guinea pig a greatly enhanced relative (% increase) reserve.
D000818:Animals; D001793:Blood Preservation; D002784:Cholesterol / Q000097:blood*; D003327:Coronary Disease / Q000097:blood; D005374:Filtration; D006168:Guinea Pigs; D006801:Humans; D007674:Kidney Diseases / Q000097:blood; D051381:Rats; D012995:Solubility; D013045:Species Specificity
D002784:Cholesterol