ラット肝温に及ぼす明暗環境の影響-2-低温暴露による肝温変動と明暗

概要

論文の詳細を見る
Liver temperatures of male Wistar rats were measured continuously by a copper-constantan thermocouple in a climatic chamber kept at 25±1°C with a light-dark cycle of LD 12:12. The rats were allowed to move relatively freely in a cage and fed on food pellets and water ad libitum.When rats were exposed to 8°C, liver temperature rose in the light period and fell in the dark period in the majority of animals.The liver temperature just prior to cold exposure distinctly influenced the pattern of temperature changes during cold exposure, but it is very probable that there are other factors which cause differences between the light and dark periods.The response of liver temperature to cold exposure varies with time in both the light and dark periods.To explain the difference in liver temperature variations during cold exposure in light and dark periods, an upper limit of metabolic rate of the liver was postulated. When cold exposure is near the upper limit, the room for additional heat production is relatively small, so heat elimination from the liver by means of hepatic blood flow may exceed heat production, and the livre temperature decreases. At lower metabolic rates, which are far below the upper limit, the liver can readily produce a considerable amount of additional heat, which may be large enough to raise the liver temperature, overcoming increased heat elimination.
日本衛生学会の論文