Training-induced changes in serum lipids, fat tolerance, and adipose tissue metabolism in patients with...

Ten males (mean age 44 years) with primary hypertriglyceridemia were trained for 4 months 3 times/week for 1-h sessions. Eleven patients with similar physical characteristics and hypertriglyceridemia served as controls. Serum was assayed for TG and cholesterol (CH) and the various lipoprotein fractions, apoprotein A-I, glucose, insulin, and C-peptide. The removal of TG from the circulation was estimated by the Intralipid test. An open fat biopsy was taken and the incorporation and esterification of [14C]palmitate and glycerol release were measured in vitro. Following endurance physical training, serum TG and VLDL-TG decreased by 25 and 27%, respectively. No changes were observed in total CH and CH in the lipoprotein fractions or in apoprotein A-I. Fat tolerance increased slightly (+8%) whereas the incorporation of labelled palmitate into adipose tissue was reduced by 16%. The diminished incorporation was concomitant with a reduction in the esterification of fatty acids to TG (-29%). Enhanced removal of TG may contribute to the lowering of serum TG. The skeletal muscle is probably responsible for this adaptation, whereas the uptake of TG into adipose tissue is diminished.