RELEASE OF AMINO-ACIDS AND RELATED-COMPOUNDS FROM THE ADRENAL EQUIVALENT AND CAUDAL VEIN OF THE EEL IN-VITRO

The release of catecholamines and cortisol from the perifused adrenal region and caudal vein of the eel (Anguilla rostrata) was compared wit h the release of 39 amino acids and related compounds, Dopamine, norep inephrine and epinephrine were present in all perifusates of the adren al region. Dopamine release from the caudal vein exceeded that from th e adrenal region, and norepinephrine and epinephrine were not detected . Cortisol was present in the perifusate of the adrenal region but vir tually absent in caudal vein perifusate. Of the six substances with kn own or suspected neurotransmitter function, taurine, aspartate, glutam ate, glycine and alanine were present in all or almost all samples fro m both the adrenal equivalent and the caudal vein, gamma-aminobutyric acid (GABA) was detected in a few samples from either preparation. The release of taurine and phosphoethanolamine may be linked to that of n orepinephrine and epinephrine. Adrenocorticotropic hormone (ACTH) enha nced the release of cortisol, aspartate, valine, leucine and ornithine from the adrenal region, but the release appears to be from differing sources or cellular pools. Overall, the study revealed that both the adrenal region and caudal vein release a large number of amino acids a nd related substances. The caudal vein, and possibly other blood vesse ls as well, may be a major source of circulating dopamine.