[Seasonal variations in epinephrine (E) and norepinephrine (NE) levels determined in organs of eel (author's transl)]

E and NE concentrations were measured by using a spectrofluorimetric method in various organs of eels, for a one year period. NE was found at higher levels than E in the whole brain, the heart, and the spleen. Maximal E levels occurred in kidney. Moreover (E + NE) sum is 40 to 190% higher than during spring and summer when compared to autumn and winter levels. According to the fact that seasonal variations of catecholamines were not found in the eel plasma, these results suggest that the observed seasonal variations can be related to fluctuation in CA amounts localized in synaptic structures.