Influence of lesion of the limbic-hypothalamic system on metabolic responses of acetate to daily repeated cold exposures in rabbits.

The effects of the lesions of basal medial hypothalamus and limbic structure on the acetate metabolic responses to daily repeated cold exposures in rabbit's liver has been investigated. The results obtained were summarized as follows: (1) The lesions of periventricular arcuate nucleus (ARC) had no effects on the acetate metabolism and on the acetate metabolic responses to the 1st cold exposure (cold exposure on the 1st day). (2) The metabolic pattern of acetate and the acetate metabolic responses to the 1st cold exposure were altered by the lesions of ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). (3) The effects of cold exposure on the acetate metabolism were completely abolished by the seven times repetition of cold exposures in the rabbits with the lesions of ARC, VMH or ST, as the same as in each sham-operated group. (4) The acetate metabolic responses to cold exposure remained after the seven times repetition of cold exposure in the rabbits with the lesions of FX, but those disappeared completely in sham-operated animals. (5) From these results, it might be suggested that the VMH, amygdala(AMYG)-ST system, dorsal hippocampus(HPC)-FX system played some roles in the metabolic regulation of acetate and in the mechanisms of acetate metabolic responses to the 1st cold exposure, but the ARC did not participate in those mechanisms. And it was suggested that the HPC-FX system participated in the acetate metabolic adaptation to daily cold exposures, but the basal medial hypothalamus and AMYG-ST system did not participate in this process.