Factors regulating blood levels of free fatty acids during alimentary lipemia.

Transient lowering of blood levels of free fatty acids (FFA) in man and experimental animals after ingestion of fat has been noted by many investigators and has been attributed to inhibition of mobilization of fatty acids from adipose tissue. Studies on lipid mobilizing activity in in vitro systems containing glucagon, insulin and anti-insulin anti-bodies as factors modifying lipolysis indicate that insulin is the basic inhibitor of lipolysis in the blood in the period immediately following feeding of animals. This observation has been confirmed by direct determinations of insulin levels by the radioimmunologic method. Experiments in which substances influencing activity of the autonomic nervous system were used show that ingestion of fats stimulates insulin secretion as a result of cholinergic stimulation. Studies on lipolytic activity of blood serum confirmed an essential role of lipoprotein lipase in the mechanism of deposition of triglycerides in adipose tissue during alimentary lipemia. The role of prostaglandins and intestinal hormones (enteroinsular axis) in the mechanism of regulation of FFA levels during alimentary lipemia is also discussed.