| Abstract: | ![]()
To investigate the involvement of adrenergic mechanisms in the development of obesity, hyperglycaemia and hyperinsulinaemia in Aston ob/ob mice, the sympathomimetic agent ephedrine (12 mg/kg/day) and the predominantly beta 1-adrenergic antagonist atenolol (12 mg/kg/day) were administered alone and in combination to weanling ob/ob mice for 40 days. Excessive weight gain in ob/ob mice was reduced (15-20%) by ephedrine, exacerbated (8-10%) by atenolol, but not significantly altered by a combination of these agents. The effects of ephedrine and atenolol were lost rapidly (within 5 days) when these agents were withdrawn. Ephedrine slightly reduced the hyperphagia in ob/ob mice, and food intake was transiently increased above that of untreated ob/ob mice when this agent was withdrawn. The development of basal hyperglycaemia and hyperinsulinaemia was not significantly altered by any of the treatments studied. None of the treatments significantly altered body weight, food intake, plasma glucose or plasma insulin concentrations in lean (+/+) mice. The results indicate that a defective adrenergic mechanism involving beta 1-adrenergic receptors contributes to the development of obesity in ob/ob mice. |
