Improved glycemic control in C57Bl/KsJ (db/db) mice after treatment with the thermogenic beta-adrenoceptor agonist, BRL 26830.

BRL 26830, (R*,R*)-(+/-)-methyl-4-(2-[(2-hydroxy-2-phenylethyl)amino]propyl)-benzoa te, is a new type of beta-adrenoceptor receptor agonist that combines antihyperglycemic and thermogenic properties. In C57Bl/KsJ db/db mice, treatment with BRL 26830 (50 mg of the hemifumarate salt/kg diet) decreased blood glucose concentration and normalized water intake. As judged by the normalization of polydipsia, BRL 26830 was effective within 2 days and the effect was maintained throughout a treatment period of up to 11 wk. Treatment of db/db mice with BRL 26830 resulted in an increase in both plasma and pancreatic insulin concentrations and a partial restoration of first-phase insulin secretion by the isolated, perfused pancreas in response to a high (16.7 mM) glucose pulse. Given acutely, BRL 26830 increased energy expenditure in both fed and fasted db/db mice. When given chronically, BRL 26830 increased significantly the dietary and thermoregulatory component of metabolic rate. It is suggested that the antidiabetic and thermogenic properties of BRL 26830 are linked and that blood glucose acts either directly or indirectly as a substrate for thermogenesis.