Stimulation of lipid absorption in young rats by cholesterol: early time changes and effects on pentobarbital sleeping time

Abstract

Four groups of young male and female rats were fed a chow diet (O), chow plus 10% corn oil (F), chow plus 1% cholesterol (C), or chow plus 1% cholesterol plus 10% corn oil (CF) for 1, 2, 4 and 8 days. After 2 dats, male F, C and CF rats exhibited a shorter anesthesia period (-20 to -30%) when given pentobarbital. By 4 days, male F and C rats had pentobarbital sleeping times (PB-ST) 20% less than O rats. These effects were additive and CF rats had 40% shorter PB-ST. Reduction of PB-ST by cholesterol and corn oil was similar but slightly less in female rats. Liver lipid content doubled in 4 days in CF rats, and liver cholesterol was 4 times than of O rats. These changes and the increases in metabolism of barbiturate suggested changes in liver microsomal enzyme activities. Serum glutamic oxaloacetic and glutamic pyruvic transaminase, two enzymes reflective of liver damage, did not increase after 8 days on C, F or CF diets. Our results suggest that consumption of an animal sterol and a high lipid diet by laboratory rats, normally consuming a diet low in fat (3-4%), increase the ability of the animal to detoxify a barbiturate. Storage of absorbed dietary cholesterol in the liver may represent a major mechanism for maintaining extra hepatic cholesterol homeostasis.