Adrenal release of catecholamines and Met-enkephalin before and after stress as measured by a novel in vivo dialysis method in the rat.

A dialysis tubing was implanted in the adrenal gland of rats. Adrenomedullary secretion products were dialysed into Ringer solution in the awake animal. Catecholamines (CAs) and methionine-enkephalin (Met-Enk) were measurable under resting conditions. Epinephrine, norepinephrine and Met-Enk-like immunoreactive material increased following application of an immobilization stress for 5 min. The results demonstrate that adrenomedullary CAs and peptides are coreleased. They also demonstrate that Met-Enk-like immunoreactive material is released under stress.