INFLUENCE OF SELECTION ON REACTION TO STRESS IN MICE .4. INFLUENCE OFFASTING IMMOBILIZATION AND EXPOSURE TO COLD ON AMINOTRANSFERASES ASPAT AND ALAT IN LIVER AND KIDNEY

The activity of alanine and asparagine aminotransferases in liver and kidney of 6-week-old mice, selected for high rates of weight gains, wa s compared to that in unselected mice. The effect of starvation, immob ilization, and cold exposure on their stress reactivity was investigat ed. The decreases in AspAT and AlAT activity, caused by 24 and 48 h st arvation, was higher in liver and kidney in selected mice than in unse lected mice, respectively. The increases in AspAT and AlAT activity ob served in liver and kidney, after 12 and 48 h immobilization and after cooling (5 degrees C, 12 h), were higher in selected than in unselect ed mice. The results seem to indicate that mice selected for a high ra te of body-weight gain are less resistant to unfavourable factors in t he environment-starvation, immobilization, cold exposure--in compariso n with unselected animals.