Release and uptake of triglycerides by isolated perfused rat liver

The uptake of triglycerides by the isolated perfused rat liver from synthetic neutral fat emulsions or from washed rat chylomicrons was investigated. It was observed that the uptake of triglycerides was more rapid in livers from starved rats than from normal fed animals. In the absence of added lipid to the perfusate, there was release of triglyceride from livers of fed animals, whereas there was a net uptake of endogenous perfusate triglyceride by livers from fasting rats. The data suggest that both uptake and release of triglyceride by liver occur simultaneously. In livers from fasted animals uptake may be the more rapid process, whereas in livers from fed rats both uptake and release may occur at more equal rates. In contrast to the triglycerides, no difference in rate of uptake of endogenous serum nonesterified fatty acid or of added fatty acid-albumin complex was observed with livers from either fed or fasting animals.