IN recent years several patients with panhypopituitarism and serum sodium concentrations as low as 106 milliequiv. per liter have been seen by us. These patients have usually had associated stressful situations and unrecognized panhypopituitarism. Present physiologic concepts suggest that the pituitary gland is of definite secondary importance in the control of aldosterone secretion and therefore a mechanism for production of hyponatremia in hypopituitarism is not readily apparent. The lack of information on the frequency and genesis of this problem was recently discussed in a clinicopathological conference in this journal.1 It is the purpose of this article, therefore, to present evidence . . .