Acute and Chronic Regulation of ob m RNA Levels by β₃-Adrenoceptor in Obese Yellow KK Mice

Abstract

The inhibitory effect of β₃-adrenoceptor agonists on the ob gene in brown adipose tissue (BAT) and white adipose tissue (WAT) is now well documented both in vivo in lean animals and in vitro, but the reported effects of β₃-adrenoceptor agonists on ob gene expression in obese animals remain controversial. We investigated whether ob gene expression in BAT and WAT is reduced by acute and chronic administrations of a β₃-adrenoceptor agonist, CL316, 243 (CL). The ob gene mRNA levels in BAT, perimetric and inguinal WAT of obese Yellow KK mice were about 4-fold higher than those of lean controls. Acute exposure (6 h) to CL decreased ob gene mRNA levels in three fat depots in both animals. Chronic exposure (10 days) to CL also decreased ob gene mRNA levels in BAT, perimetric, and inguinal WAT in both animals. We concluded that acute and chronic regulation by a β₃-adrenoceptor agonist suppressed ob gene expression in obese Yellow KK mice and lean cotrols.