Cafeteria feeding promotes diet-induced thermogenesis in monosodium glutamate-treated mice.

We studied diet-induced thermogenesis (DIT) in cafeteria fed monosodium glutamate (MSG) and saline-treated mice. From 12 weeks of age MSG and saline-treated mice were fed a diet of either standard chow or a cafeteria diet of standard chow supplemented with chocolate or biscuits on alternate days for six weeks. There was a significant weight gain in cafeteria fed MSG-treated mice but not in cafeteria fed saline-treated mice. In cafeteria fed MSG-treated mice there was a significant increase in resting oxygen consumption. The response to exogenous norepinephrine was significantly increased in cafeteria fed saline-treated mice. The level of specific tritiated guanosine 5'-diphosphate binding to isolated mitochondrial fractions was significantly increased in both cafeteria fed MSG and saline-treated mice. It is concluded that (1) cafeteria feeding is capable of promoting DIT, within brown adipose tissue (BAT), in MSG-treated mice and (2) the mechanisms for the induction of thermoregulatory thermogenesis (TRT) and DIT are distinct since cold-induced TRT has previously been shown to be defective in MSG-treated mice.