Reduced norepinephrine turnover in mice with monosodium glutamate-induced obesity.

The disappearance of norepinephrine from the heart, interscapular brown adipose tissue (BAT), and pancreas has been examined in mice with monosodium glutamate (MSG)-induced obesity and in untreated controls. MSG-treated mice became obese in the absence of increased food intake and their core temperature was significantly lower compared to control mice. The rate of norepinephrine turnover following blockade of norepinephrine synthesis with alpha-methyl-para-tyrosine was significantly slower in heart and interscapular BAT of these mice than in untreated controls, but MSG had no effect on the pancreas. It is suggested that reduced norepinephrine turnover may be a major factor in the development of obesity after neonatal administration of MSG.