Fast elevation of the intramyocellular lipid content in the presence of circulating free fatty acids and hyperinsulinemia: A dynamic H-1-MRS study

The influence of a short-term elevation of free fatty acids (FFAs) on intra myocellular lipids (IMCL) under hyperinsulinemic conditions was monitored i n five healthy male subjects in the course of a 5-hr hyperinsulinemic gluco se clamp. During the glucose clamp a lipid emulsion (Intralipid 20(R)) and heparin were administered intravenously. IMCL was quantified in the tibiali s anterior (TA) and the soleus (SOL) muscle by H-1-MRS. A rapid elevation o f the IMCL pool was found in both muscles (61% in TA and 22% in SOL) in the 5-hr time period. A control hyperinsulinemic glucose clamp in the same stu dy group, repeated without elevation of circulating FFAs, did not lead to s ignificant changes in IMCL for both muscles. The present study shows for th e first time that only the combination of high concentrations of FFAs and i nsulin lead to marked storage of lipids in skeletal muscle cells in humans. Magn Reson Med 45:179-183, 2001, (C) 2001 Wiley-Liss, Inc.