THE EFFECT OF VENTRAL HYPOTHALAMIC LESIONS ON SODIUM AND POTASSIUM METABOLISM IN THE DOG1,2

Abstract

The urinary excretion and plasma levels of sodium and potassium in 1.8 dogs with ventral hypothalamic lesions have been compared to those found in normal, hypophysectomized and adrenalectomized animals on a daily diet containing 40 m.eq. of sodium and 8 m.eq. of potassium, on a diet containing 0.5 m.eq. of sodium and 50 m.eq. of potassium, and after the intravenous administration of a salt load equivalent to 5.13 m.eq. per kilogram of body weight. The ventral hypothalamic lesions produced diabetes insipidus, gonadal atrophy and/or inhibition of hydroxycorticoid secretion in response to surgical trauma in a large number of the animals studied. However, none of the animals showed abnormal sodium and potassium metabolism and all withstood salt restriction and handled a salt load in a normal fashion. Hypophysectomized dogs also responded normally, but adrenalectomized dogs, maintained before and during the diet studies on hydrocortisone alone, became hyponatremic and died when subjected to salt restriction.