THE EFFECTS OF THYROIDECTOMY, CASTRATION, ANTERIOR LOBE ADMINISTRATION AND PREGNANCY UPON EXPERIMENTAL DIABETES INSIPIDUS IN THE CAT

Abstract

In a series of papers dealing with the experimental production of polyuria in cats and monkeys (1, 2, 3) evidence has been presented to show that permanent polyuria as produced in such forms is associated with lesions interrupting the nervous pathway extending from the nucleus supraopticus to the posterior hypophysis. In these cases there is atrophy of the supraoptic nuclei and of the pars nervosa of the hypophysis, and such atrophic glands have been found to be deficient in content of antidiuretic, pressor and oxytocic principles (4). It has been further shown that polyuria may occur in cats following direct removal of the posterior lobe including the stalk, providing functional anterior lobe tissue is left (5). Cats with diabetes insipidus, or even a latent tendency that way due to partial interference with the supraoptico-hypophyseal system, are unusually sensitive to the diuretic effects of thyroid and salt feeding, but thyroidectomy, while diminishing the intensity of the polyuria, has not in our experience completely eliminated the excessive water exchange (6). The present communication deals with further experiments on the effect of thyroidectomy upon cats with diabetes insipidus, and with other observations on the influence of castration, administration of a crude anterior lobe extract and pregnancy.