Ball, Wilmot C.

Effects of hypophysectomy on aldosterone and sodium excretion were studied in a group of seven dogs with ascites secondary to thoracic inferior vena cava constriction. In another group of three dogs, the pituitary was removed first and after 6–8 weeks the thoracic inferior vena cava was constricted. Following hypophysectomy of the seven dogs with the initial ascites, aldosterone became undetectable in urine and sodium excretion increased concurrently; adrenocorticotrophic hormone (ACTH) failed to prevent these effects. However, additional constriction of the vena cava with a consequent further elevation in venous pressure was followed by a return of nearly complete sodium retention. In two of the dogs in which hypophysectomy was performed first and the thoracic inferior vena cava constricted later, there resulted increased aldosterone output, marked sodium retention and ascites. In these dogs the adrenal cortex was markedly atrophic but the atrophy was limited to the two inner layers. The data suggest that in pathological states accompanied by edema and ascites the increased excretion and presumably increased secretion of aldosterone are not solely dependent upon pituitary hormonal function.

Effects of hypothalamic lesions were studied in 10 dogs with chronic ascites produced by constriction of the thoracic inferior vena cava. During the first three postoperative days, the high rate of urinary aldosterone excretion and the marked Na retention characteristic of dogs with chronic experimental ascites were unaltered in all 10 animals. Every area of the hypothalamus was destroyed bilaterally in at least one animal. Seven of the 10 dogs survived the subacute 3-day period; two dogs died after 6 days but five animals lived for 2 weeks or longer. In these seven animals, aldosterone excretion in urine remained elevated above normal although in three animals a progressive decline occurred; sodium excretion remained low in all seven dogs surviving the subacute period. In the three animals in which aldosterone output declined, there was bilateral injury of the median eminence and adrenal atrophy. The data show that chronic hypothalamic lesions were without effect unless the median eminence was injured.