The metabolic response of muscle tissue to
glucose ingestion was studied in 10 normal men (M) and women (F) by using the forearm balance technique and indirect calorimetry simultaneously. During the 3 hours after a 75 g--oral
glucose load,
glucose uptake per unit muscle mass was significantly higher in women than in men, F = 187.3 +/- 26.9 vs M = 116.7 +/- 9.5 mg/100 g forearm muscle (P less than 0.05). A significant difference in muscle
glucose fate was also observed since the amount of
glucose utilized through a nonoxidative pathway was significantly higher in women, F = 84.5 +/- 2.6% (161.8 +/- 27.3 mg/100 g forearm muscle) vs M = 75.3 +/- 2.2% (87.2 +/- 8.6 mg/100 g forearm muscle) (P less than 0.05), whereas the amount of
glucose oxidized in relation to
glucose uptake was significantly higher in men, M = 24.7 +/- 2.2% (28.2 +/- 3.2 mg/100 g forearm muscle) vs F = 15.5 +/- 2.6% (27.8 +/- 5.4 mg/100 g forearm muscle) (P less than 0.05). No significant differences in
insulin response to
glucose ingestion were detected between groups. The women showed greater suppression of serum
free fatty acids (FFA) levels in relation to basal levels than men. We conclude that: 1) after ingesting 75 g
glucose, normal women showed greater
glucose uptake per unit muscle mass than normal
men, 2) for 3 hours after the ingestion of 75 g
glucose, the predominant tendency toward utilizing
glucose by a nonoxidative pathway is more marked in normal women than in normal men, and 3) the higher
glucose uptake per unit muscle mass in the female group in the presence of an
insulin response not significantly different from that of the male group suggests that muscle
insulin sensitivity is greater in normal women.