Release of antidiuretic hormone from neurohypophysis in response to hemorrhage and infusion of hypertonic saline in dogs.

Abstract

Plasma hypertonicity and hemorrhage cause release of antidiuretic hormone (ADH) from the neurohypophysis. In order to elucidate the location of the pathways through which osmotic and hemorrhagic stimuli influence the neurohypophysis, hypertonic saline infusion and hemorrhage experiments were performed in dogs. The plasma ADH titers were measured before and after the infusion or the hemorrhage. A significant increase in plasma ADH titers was seen in intact dogs and dogs with diencephalic islands after infusion of hypertonic saline. In response to hemorrhage, intact dogs showed a massive increase in ADH levels in plasma. Decerebrated dogs and dogs with diencephalic islands failed to increase ADH levels in plasma after hemorrhage, whereas decorticated dogs and dogs with their spinal cord sectioned at the level of C-l showed great responses. Dogs with abdominal vagus nerves sectioned also showed a marked increase in ADH levels in plasma in response to hemorrhage. Significant rises in ADH titers in plasma afte...