Removal of exogenous triglycerides in human forearm muscle and subcutaneous tissue

The removal of exogenous triglyceride (TG) in forearm muscle and subcutaneous tissue of 7 healthy male volunteers has been studied by nephelometric determinations of arterial-deep venous (a-dv) and arterial-superficial venous (a-sv) differences in concentration of fat particles. Exogenous TG was administered as a constant i.v. infusion of Intralipid over a period of 30 min at reat and another 15 min during forearm work. At rest a significant positive a-dv difference in fat particle concentration of 121 plus pr minus 21 mumol TG/l (mean plus or minus S.E.M.) was found, which correspondens to a fractional extraction of 1093 plus or minus 2.0%. Also the a-sv difference was significant, 81 plus or minus 14 mumol TG/l, 5.7 plus or minus 0.8% of the arterial concentration. During exercise no further significant removal was found. Thus both skeletal muscle and subcutaneous tissue seem to be able to remove exogenous TG in substantial amounts under resting conditions. In the exercising muscle, however, the direct removal of exogenous TG does not seem to be of significant importance.