THERMOGENESIS AFTER A MIXED MEAL - ROLE OF LEG AND SPLANCHNIC TISSUESIN MEN AND WOMEN

To determine the relative contribution of splanchnic and leg tissues t o postprandial thermogenesis, systemic and regional oxygen consumption rates were measured in nine women and eight men before and for 6 h af ter the consumption of a mired meal that provided one-third of the dai ly energy needs. In women, the increase in splanchnic oxygen uptake ac counted for 63 +/- 12% of the postprandial increase in oxygen consumpt ion, whereas in men it accounted for 35 +/- 14% (P = not significant b etween women and men). Leg oxygen uptake accounted for 11 +/- 4 and 10 +/- 3% of the increase in postprandial oxygen consumption in women an d men, respectively, The combined data suggest that similar to 48% of postprandial thermogenesis over 6 h occurs in splanchnic tissues, wher eas 30-35% occurs in skeletal muscle. Thus the increase in oxygen cons umption after a mixed meal is primarily localized to splanchnic tissue s, and major reductions in postprandial thermogenesis are unlikely to be attributable solely to abnormalities of skeletal muscle metabolism.