Abstract
The effects of hypophysectomy on mammals and amphibians have been extensively investigated, but apparently no work of this nature has been done on reptiles. The present study on garter snakes (Thamnophis sirtalis and T. radix) was made to determine whether or not hypophysectomy of reptiles produces the same results known for other vertebrates. Several male snakes were hypo-physectomized to determine the histological changes of the endocrine organs, while others were given homeoplastic hypophyseal implants.
The testes of hypophysectomized animals became small and flaccid with degenerating spermatocytes in the atretic seminiferous tubules, while the size of the interstitial cells was less than normal. Subcutaneous implantation of a single hypophysis every other day for a period of 30 days, elicited germ cell production, enlarged the tubules, and increased the size of the interstitial cells. The adrenal glands after hypophysectomy were reduced to about two-thirds normal size. The cortical cells were atretic, and most of the nuclei had migrated to the periphery of the cell cluster. No retrogressive changes were noticed, however, in the cells of the medullary tissue. Hypophyseal implants, as given, did not restore the normal size of the gland, but the cells regained approximately their normal appearance and nuclear distribution.
The acinar epithelium of the thyroid gland, which is normally cuboidal, was, after hypophysectomy, reduced to a squamous type and these modifications were definitely although not entirely corrected by hypophyseal implants. Removal of the hypophysis also invariably caused shedding† of the skin which appeared to be due to thyroid disturbance.
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