Decreased Resistance to Hemorrhage in Neurohypophysectomized Dogs

Abstract
The diabetes insipidus dog is more susceptible to hemorrhage than the normal dog as determined by a standardized hemorrhage procedure. When aqueous pitressin is administered in subpressor dosages, this susceptibility to hemorrhage is reversed to or toward normal. Aqueous pitressin does not increase the intact dog's resistance to hemorrhage. The foregoing observations are interpreted as demonstrating that the neurohypophysial pressor principle serves a physiologic role in maintaining blood pressure during hemorrhage.