Mitigation of obesity by BRL 26830A, a new beta-adrenoceptor agonist, in MSG obese mice

Half of the mice in both the monosodium-L-glutamate (MSG)-induced obesity and saline control groups were given BRL 26830A via a gastric tube at a daily dose of 5 mg/kg for 2 weeks, and the other half given distilled water. BRL 26830A administration significantly increased guanosine-5'-diphosphate (GDP)-binding in brown adipose tissue (BAT) and the resting metabolic rate (RMR), and significantly reduced retroperitoneal white adipose tissue (WAT) pads in both groups. It also markedly reduced body weight in MSG obese mice that had reduced BAT thermogenesis and decreased RMR. However, food intake was unchanged in both groups. Neither beta 1- nor beta 2-selective antagonists affected the increase of RMR induced by BRL 26830A, but a non-selective beta-antagonist completely inhibited its increase. These results suggest that BRL 26830A, which is a new beta-adrenoceptor agonist, stimulates BAT thermogenesis, increases RMR, and reduces WAT, thus contributing to the mitigation of obesity.