ENHANCED THERMOGENIC RESPONSIVENESS DURING CHRONIC EPHEDRINE TREATMENT IN MAN

The thermogenic effect of a single oral dose of ephedrine (1 mg/kg body weight) was studied by indirect calorimetry in 5 women with 14% overweight before, during and 2 mo. after 3 mo. of chronic ephedrine treatment (20 mg, perorally, 3 times daily). Before treatment and 2 mo. after its cessation a similar thermogenic response to ephedrine was observed. The total extra consumption of O2 was 1.3 l before and 1.2 l after cessation of the chronic treatment. After 4 and 12 wk of treatment ephedrine elicited a more sustained response, the extra O2 consumption in the 3 h following ephedrine intake being 7.0 and 6.9 l, respectively. The ratio of serum T3 [triiodothyronine] to T4 [thyrofine] increased significantly after 4 wk of treatment (15.6 .+-. 1.3 vs. 19.4 .+-. 2.4; P < 0.05), but decreased below the initial value after 12 wk treatment. The mean body weight was significantly reduced after 4 and 12 wk of treatment (2.5 and 5.5 kg, respectively). An improved capacity for .beta.-adrenergic induced thermogenesis may be useful in the treatment of obesity.