Vasopressin release during sepsis and septic shock in baboons and dogs.

Plasma vasopressin concentration was measured by radioimmunoassay in lightly anesthetized baboons and dogs before and during experimental Escherichia coli septic shock. Since vasopressin is a potent vasoconstrictor, and activator of clotting factors and a myocardial depressant, we postulated that, if found in substantial amounts in the plasma, vasopressin may contribute to the physiopathology of the septic shock syndrome. Quite high plasma vasopressin concentrations were found in both baboons and dogs. In the baboons, increased plasma vasopressin concentrations occurred, while mean arterial blood pressure was still within normal limits and remained elevated for as long as 12 hours during septic shock. Plasma vasopressin concentrations of this magnitude have been previously reported only with direct hypothalamic stimulation or after hypotensive shock secondary to hemorrhage.