EFFECTS OF HYPOPHYSECTOMY AND REPLACEMENT THERAPY ON THE THYROID AND ADRENAL GLANDS OF THE MALE GROUND SQUIRREL1

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Abstract
This report deals with 86 hypophysectomized [male] ground squirrels (Citellus tridecemlineatus) which were found by study of serial sections of the sphenoid bone to lack pars distalis tissue. 28 were uninjected controls, 56 injected. Data for 15 normal [male][male] are included. Hypophysectomy in the [male] abolished the annual cycle of the thyroid gland. The thyroid of hypophysectomized [male][male] showed histo-logical evidence of low physiological activity and resembled the thyroid of ground squirrels during the hibernating period. The adrenal gland of the hypophysectomized [male] undergoes marked atrophy, particularly evident in the cortex. The fasciculate and outer reticular zones disappear, and degenerative changes become prominent in the cortex, especially in the dedifferentiated reticular zone. Adm. of testosterone and testosterone propionate by subcut. inj. to hypophysectomized [male][male] failed to stimulate the thyroid or to prevent the atrophy of the adrenal. Of the gonado-trophic substances injected subcut. into hypophysectomized [male][male], gonadin stimulated slightly the thyroid and not only prevented the involution of the adrenal, but also resulted in cortical hypertrophy. Antuitrin S and prospermin prevented adrenal atrophy and stimulated the adrenal cortex, but had no effect on the hypophysectomy thyroid. The pituitary gland appears necessary for the normal functioning of the thyroid and adrenal of the [male] ground squirrel (Citellus tridecemlineatus) and for the maintenance of the annual cycles of these glands in this spp.