A possible role of circulating lipoprotein-triglycerides in the increase in concentration of free fatty acids and in insulin resistance in "total" lipodystrophy.

Abstract

The mechanism responsible for the increase in concentration of free fatty acids in lipodystrophy was investigated in a 20-yr-old woman with a total absence of adipose tissues. The fasting concentration of plasma free fatty acid was not related to either the concentration of plasma glucose, immunoreactive insulin or growth hormone. The concentration of free fatty acid and glycerol did not increase significantly after the administration of norepinephrine. During a period on a high-fat diet the concentration of free fatty acids increased, and this was associated with an increase in the concentration of plasma triglycerides. The composition of free fatty acids in plasma closely resembled that of the plasma triglycerides. Post-heparin lipoprotein lipase activity was normal. It is suggested that circulating lipoprotein triglyceride was hydrolyzed by lipoprotein lipase on capillary surfaces at the peripheral sites and the resultant free fatty acids entered the circulation instead of being taken up by adipocytes, which were totally lacking in the patient. Insulinresistance decreased when the concentration of plasma free fatty acids decreased, suggesting that the elevation of free fatty acids was responsible for insulin-resistance in total lipodystrophy.