Gwosdow A R, Besch E L, Chen C L
J Appl Physiol (1985). 1985 Aug;59(2):408-12. doi: 10.1152/jappl.1985.59.2.408.
The physiological changes in male rats during acclimation were studied following direct or stepwise exposure to heat (32.5 degrees C) in a controlled-environment room. The animals were exposed to each temperature for 10 days beginning at 24.5 degrees C and returning to 24.5 degrees C in the reverse order of initial exposure. Relative humidity of 50 +/- 2% and a 12-h light-dark photoperiod (light from 0900 to 2100 h) were maintained. Physiological changes in metabolic rate (MR), evaporative water loss (EWL), plasma corticosterone, body water turnover, and food and water intake were measured. The results indicate a significantly (P less than 0.001) elevated plasma corticosterone and MR in rats exposed directly to heat from control temperature (24.5 degrees C) but not in those animals exposed stepwise via 29.0 degrees C. All kinetic parameters of water pool changed (P less than 0.01) on direct exposure to heat, whereas rats exposed in a stepwise manner increased only pool turnover. In addition, exposure to experimental temperatures resulted in reduced (P less than 0.05) relative food intake and increased (P less than 0.05) water intake. Compared with the control condition of 24.5 degrees C, EWL was significantly (P less than 0.05) elevated when the animals were exposed either directly or in a stepwise fashion to 32.5 degrees C. These data suggest that the response to elevated temperatures is influenced by the temperature to which the rat is acclimated.
在可控环境室内，对雄性大鼠直接或逐步暴露于热环境（32.5摄氏度）后的适应过程中的生理变化进行了研究。从24.5摄氏度开始，将动物暴露于每个温度下10天，然后以与初始暴露相反的顺序回到24.5摄氏度。保持相对湿度为50±2%，以及12小时的明暗光周期（0900至2100时为光照）。测量了代谢率（MR）、蒸发失水（EWL）、血浆皮质酮、身体水分周转率以及食物和水摄入量的生理变化。结果表明，直接从对照温度（24.5摄氏度）暴露于热环境的大鼠血浆皮质酮和MR显著升高（P<0.001），但通过29.0摄氏度逐步暴露的动物则没有。直接暴露于热环境时，水池的所有动力学参数均发生变化（P<0.01），而逐步暴露的大鼠仅水池周转率增加。此外，暴露于实验温度导致相对食物摄入量减少（P<0.05），水摄入量增加（P<0.05）。与24.5摄氏度的对照条件相比，当动物直接或逐步暴露于32.5摄氏度时，EWL显著升高（P<0.05）。这些数据表明，大鼠对温度升高的反应受其适应温度的影响。
