Groups of normal (nonoperated), two-month-old and eight-month-old rats were subjected to a daily buzzer and electric shock stress program for five weeks. Blood sugardeterminations were made immediately before and after ninety-minute stress (experimental group) or rest periods (controls). There was a small but statistically highly significant increase in blood sugar after stress compared to the prestress values at both age periods. This increase was much bigger in the older than in the younger group of fasted normal rats.
Groups of adrenalectomized animals subjected to the same stress program never showed any significant blood sugar increase after stress. Indeed the nonfasted, recently operated, two-month-old rats displayed a highly significant drop in blood sugar after stress.
Recently hypophysectomized, two-month-old nonfasted rats showed a decrease in blood sugar after stress but their nonstressed controls showed a similar decrease. Fasting two-month-old, hypophysectomized rats were found to have an insignificant increase after stress which became significant only when compared to the drop in blood sugar of their nonstressed controls. In contrast eight- and ten-month-old hypophysectomized fasted rats showed a highly significant increase in blood sugar after stress. Moreover, the magnitude of this increase was much greater in those rats in which more than six months had elapsed sincethe operation compared to the recently hypophysectomized animals of approximately the same age. Thus the influence of both the time lapse since the operation and the age of the animals on the blood sugar response to stress is demonstrated in the hypophysectomized rats.