Influence of Lesions in the Limbic-Hypothalamic System on Insulin Responses to Daily Repeated Cold Exposures in Rabbits

K. Seto; H. Saito; H. Kaba; Y. Sasaki; T. Tsuda; M. Kawakami†

doi:10.1055/s-0029-1210368

Experimental and Clinical Endocrinology & Diabetes, Table of Contents

Exp Clin Endocrinol Diabetes 1984; 84(4): 71-80
DOI: 10.1055/s-0029-1210368

Original

Influence of Lesions in the Limbic-Hypothalamic System on Insulin Responses to Daily Repeated Cold Exposures in Rabbits

K. Seto, H. Saito, H. Kaba, Y. Sasaki¹ , T. Tsuda¹ , M. Kawakami†²

¹First Department of Physiology (Chairman: Prof. Dr. K. Seto), Kochi Medical School, Nankoku, Laboratory of Animal Physiology, Faculty of Agriculture (Head and Dean: Prof. Dr. T. Tsuda), Tohoku University, Sendai, Yokohama/Japan
²Second Department of Physiology, Yokohama City University School of Medicine, Yokohama/Japan

Abstract

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Summary

The effects of lesions in the basal medial hypothalamus and limbic structures on the responses in plasma levels of insulin and glucose to daily repeated cold exposure in rabbits have been investigated. The results obtained were summarized as follows: (1) The 1st cold exposure (cold exposure on the 1st day) decreased insulin levels and increased glucose levels, and these responses of insulin and glucose to cold exposure gradually decreased and then completely abolished by daily repetition of exposures in intact rabbits and each sham-operated group. (2) The lesions of periventricular arcuate nucleus (ARC), stria terminalis (ST) and dorsal fornix (FX) had no effects on the insulin responses to the 1st cold exposure, but the rates of insulin responses to the 1st cold exposure were decreased by the lesions of ventromedial hypothalamus (VMH). (3) The ARC lesions had no effects on the glucose responses to the 1st cold exposure, but the glucose responses to the 1st cold exposure were abolished by VMH lesions and were altered by lesions of ST and FX. (4) The insulin responses to cold exposure were abolished by daily repetition of exposures in rabbits with ARC lesions as same in the cases of sham-operated animals, but the insulin responses to cold exposure persisted even after daily repetition of exposures in rabbits with lesions of VMH, ST and FX different from sham-operated animals. (5) The glucose responses to cold exposure were abolished by daily repetition of exposures in rabbits with lesions of ARC and ST as same as in the cases of sham-operated animals, but the glucose responses to cold exposure persisted even after daily repetition of exposures in rabbits with FX lesions different from sham-operated animals.

Key words

Cold exposure - basal medial hypothalamus - insulin - glucose

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