ALDOSTERONE SECRETION IN DOGS WITH HYPOTHALAMIC LESIONS12

Abstract

Aldosterone and 17-hydroxycorticoid secretion have been measured by collecting the effluent blood from the right adrenal in 6 dogs with lesions of the anterior median eminence, and 6 dogs with lesions elsewhere in the hypothalamus. These values have been compared to those obtained in 6 normal and 4 hypophysectomized dogs. Sodium and potassium levels in serum and urine have also been measured on a normal and a low sodium intake. Lesions of the anterior median eminence which inhibit hydroxycorticoid secretion have no effect on sodium and potassium metabolism, but are associated with a reduced aldosterone secretion in the adrenal venous blood after acute cannulation of the adrenal. Similar results, i.e., moderate impairment of aldosterone secretion in the absence of any detectable abnormality of sodium and potassium metabolism, were obtained in the hypoplsectomized dogs.It is suggested that the observed differences between normal dogs and dogs with lesions of the median eminence are due to decreased ACTH secretion in response to the trauma of drenal cannulation, rather than any direct effect on the mechanism regulating aldosterone secretion in response to changes in sodium and potassium intake.