Adrenal medullary secretion of dopamine in response to hemorrhagic and endotoxin-induced shock in dogs.

Adrenal medullary secretion of dopamine (DA) was investigated during acute hemorrhagic and endotoxin-induced shock in mongrel dogs. Blood samples were collected directly from the adrenal vein and DA content was measured using gas-liquid chromatography equipped with an electron-capture detector (GLC-ECD). The adrenal medullary secretion of DA increased markedly during hemorrhagic and endotoxin-induced shock. In the former, the rate of secretion of DA increased from 0.22 ng/kg/min to 10.7 ng/kg/min in 90 min. After blood transfusion, the rate of secretion of DA decreased rapidly. In the case of endotoxin-induced shock, the rate of secretion of DA increased from 0.20 ng/kg/min to 9.6 ng/kg/min in 120 min. In the cervical spinal transected dogs, the rate of secretion of DA did not increase during hemorrhagic shock. Thus, secretion of DA from the adrenal medulla seems to be primarily controlled by the central nervous system, through the baroreceptor reflex.