Rat plasma cholesterol after particulate triacylglycerol clearance.

Following clearance of plasma cholesterol-rich triacylglycerol emulsions, lower-density lipoprotein cholesterol increased minimally in chow and considerably in cholesterol-fed rats. Cholesterol-poor chylomicrons and enteral triacylglycerol produced similar lipoprotein cholesterol increases in cholesterol-fed rats indicating tissue cholesterol recruitment after particulate triacylglycerol clearance. No plasma cholesterol increment was found after chylomicron clearance in anhepatic cholesterol fed rats demonstrating the liver as the major tissue source. The post triacylglycerol clearance was not due to the influx of fatty acid into the liver since larger hepatic free fatty acid loads produced no plasma cholesterol increment. This plasma cholesterol response to particulate triacylglycerol flux occurs only when the liver has excess cholesterol and if applicable to man, may be a factor explaining the large plasma cholesterol differences between diets rich and poor in lipid.