Certain aspects of cholesterol metabolism and hepatic protein synthesis in the rat

Abstract

Hepatic protein synthesis was studied in rats fed a hypercholesteremic diet, containing cholesterol and cholic acid, and high in fat. If such a diet was fed for periods of at least 4 weeks a lowered capacity of amino acid incorporation into liver protein in vivo and in vitro was observed. The animals selected were rats which had been previously characterized by such a dietary assay as being neither refractory nor susceptible to induction of high serum cholesterol levels. When "hypo-responders" (i.e., rats which are relatively refractory to hypercholesteremia) were compared to "hyper-responders" significant differences in protein synthesis in vivo were observed after only 2 weeks of dietary treatment; the capacity for incorporation of amino acids in the livers of hyper-responders was significantly lower than that in the hypo-responders. Several studies were also carried out in vitro including an attempt to determine which intracellular components of the liver may be affected; it appears that the defect(s) is primarily related to the endoplasmic reticulum. Thus, diet may act as the modus operandi for revealing any purported inherent defect(s).