Hepatic selective adjustments in short-term cold exposed rats.

The metabolic adjustments which occur in rat liver cells during the first days of cold exposure have been investigated. We have measured both mitochondrial mass and oxidative capacities as well as ATP production after five and 10 days of cold exposure. In addition, we have measured plasma membrane Na+/K(+)-ATPase activity. Cold exposure elicited a significant increase in mitochondrial mass as well as in state 3 oxidative rates and ATP production in isolated mitochondria using various substrates. Moreover, our results show that Na(+)-pumping activity significantly increased after both five and 10 days of cold exposure. Our results suggest that during the first days of cold exposure liver cells undergo alterations which are useful for survival in the cold.