OBJECTIVE-Kinins mediate pathophysiological processes related to hypertension, pain, and inflammation through the activation of two G-protein-coupled receptors, named B 1 and B 2 . Although these peptides have been related to glucose homeostasis, their effects on energy balance are still unknown.RESEARCH DESIGN AND METHODS-Using genetic and pharmacological strategies to abrogate the kinin B 1 receptor in different animal models of obesity, here we present evidence of a novel role for kinins in the regulation of satiety and adiposity.
RESULTS-Kinin B 1 receptor deficiency in mice (B 1Ϫ/Ϫ ) resulted in less fat content, hypoleptinemia, increased leptin sensitivity, and robust protection against high-fat diet-induced weight gain. Under high-fat diet, B 1 Ϫ/Ϫ also exhibited reduced food intake, improved lipid oxidation, and increased energy expenditure. Surprisingly, B 1 receptor deficiency was not able to decrease food intake and adiposity in obese mice lacking leptin (ob/ob-B 1 Ϫ/Ϫ ). However, ob/ob-B 1 Ϫ/Ϫ mice were more responsive to the effects of exogenous leptin on body weight and food intake, suggesting that B 1 receptors may be dependent on leptin to display their metabolic roles. Finally, inhibition of weight gain and food intake by B 1 receptor ablation was pharmacologically confirmed by long-term administration of the kinin B 1 receptor antagonist SSR240612 to mice under high-fat diet.CONCLUSIONS-Our data suggest that kinin B 1 receptors participate in the regulation of the energy balance via a mechanism that could involve the modulation of leptin sensitivity.