FATTY-ACID INCORPORATION INTO HUMAN ADIPOSE-TISSUE IN HYPERTRIGLYCERIDEMIA

The fatty acid and glucose incorporation into glycerides and glycerol release from adipose tissue were determined in a middle-aged population of 109 men and 41 women. (43 men and 19 women were normolipidemic) and in 13 male and 9 female normolipidemic students. Needle biopsy specimens of adipose tissue were incubated in vitro in an albumin medium containing 3H-fatty acids and 14C-glucose. After 2 h of incubation, values for fatty acid and glucose incorporation were calculated from the incorporation of 3H-activity into the fatty acids and 14C-activity into the glycerol moiety of extracted glycerides. The mean values for fatty acid incorporation were lower in all types of hypertriglyceridemic subjects (II B, III, IV and V) than in the normolipidemic control subjects. In the male hypertriglyceridemic population 36% had values for fatty acid incorporation below the 5th percentile of the normolipidemic group and 14% had values below the lowest normal value. The rate of fatty acid incorporation was negatively correlated with the serum triglyceride concentration. This correlation was not changed when corrected for body weight. Similar data was obtained for glucose incorporation. Fatty acid and glucose incorporation correlated positively. Glycerol and fatty acid release was the same in the normo- and hypertriglyceridemic groups. The removal of plasma triglycerides from blood may require hydrolysis of triglycerides to fatty acids and subsequent removal of the fatty acids. When the former process is normal, a defect of fatty acid removal (a low rate of fatty acid incorporation into glycerides) may be responsible for an impaired removal of plasma triglyceride-fatty acids. A low rate of fatty acid incorporation may contribute to the development of hypertriglyceridemia, according to this hypothesis.