The sibutramine metabolite M2 improves muscle glucose uptake and reduces hepatic glucose output: preliminary data

The satiety agent sibutramine acts in part through a primary amine metabolite, M2. To investigate whether M2 could affect glycaemia independently of satiety and weight loss, groups of normal mice received a single dose of M2 (1 or 10 mg/kg) and food was withheld. Compared with controls (who received vehicle only), M2 (10 mg/kg) decreased basal plasma glucose concentrations, with a maximal decrease of about 25% at 48 hours (p < 0.05). Soleus muscles were isolated from the mice at intervals: insulin-mediated glucose uptake by the muscles from controls progressively decreased over 24 hours whereas uptake was maintained by muscles from M2-treated mice. Hepatic gluconeogenesis was reduced about 40% by liver snips isolated from M2-treated mice after 24 hours (p < 0.05). These preliminary results suggest that the M2 metabolite of sibutramine can reduce glycaemia, maintain insulin-mediated muscle glucose uptake and reduce hepatic gluconeogenesis independently of satiety and weight loss.