The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: appendix I. Condition of flight animals on recovery; food intake; observations on hypothalamus, pituitary, and adrenal glands.

The rationale for studying certain hypothalamic nuclei and the pituitary and adrenal glands of the pocket mice that flew on Apollo XVII was the need to evaluate the effects of the potentially severe stress on these animals in the foreign environment of flight canister, weightlessness, increased G forces, and other unnatural conditions. Decrease in body weight and variability of food intake were significant among the four flight animals that were recovered alive. The mean nuclear diameter of neurons in the arcuate and ventromedial hypothalamic nuclei did not differ significantly from the values obtained in the control animals. On the other hand, the mean nuclear diameter of neurons in the supraoptic nucleus of the flight mice was significantly greater than in the control groups. Comparisons of the adeno- and neuropypophysis revealed no significant differences among the three groups. Insofar as they were studied, the adrenals were similar in all groups.