There are many conflicting reports on the acute effects of posterior pituitary extract on the renal excretion of sodium and chloride. This subject has been recently reviewed (1). The present study was made to' determine the effects on electrolyte excretion in man of a longacting posterior pituitary extract administered over a period of several days. The results suggest that the state of hydration determines the effect of pitressin on electrolyte excretion. The relationship of the findings to the problem of volume regulation of the body fluids will be considered.

In 1918 von Hann (1) suggested, as a result of her post mortem studies in man, that destruction of the posterior pituitary caused diabetes insipidus only if significant portions of the anterior pituitary gland remained intact. This observation has been supported by other workers who noted that in experimental diabetes insipidus, destruction of the anterior pituitary resulted in decrease in the polyuria and polydipsia (2-7). In 1935 Mahoney and Sheehan (8) showed that experimental diabetes insipidus in the dog can be ameliorated by thyroidectomy and the polyuria can be reestablished by thyroid feeding. Fisher, Ingram and Ranson (9) confirmed this result in experimental diabetes insipidus as have others (6, 7, 10-14). Similar relationships for adrenal cortical activity to the diabetes insipidus state have been claimed (15, 16) and much has been said regarding the diuretic action of adrenal hormones (16, 17). It should be stressed that all this work was done on animals in which the degree of polyuria and polydipsia was the sole criterion of the diabetes insipidus state. This study was done on a patient who had, in addition to well documented neurohypophyseal insufficiency, evidence of some concomitant anterior pituitary failure. The purpose of this paper is to reemphasize the physiological defect in diabetes insipidus; and to study its relationship to solute loading, thyroid, adrenal, and anterior pituitary function. The findings clearly show that polyuria and polydipsia are not necessary accompaniments of insufficiency of the supraopticohypophyseal system and suggest that the anterior pituitary,

The work of Verney (1, 2) has clearly demonstrated that the antidiuretic mechanism of the