Seasonal variations in circadian rhythm of hypothalamic catecholamine content in the eel (Anguilla anguilla L.).
1. Changes in catecholamine content (CA) in hypothalamus of male and female eel (Anguilla anguilla L.) were defined using the Falck-Hillarp histochemical fluorescence method for a 24-hr period during the summer (L:D = 16:8) and winter (L:D = 8:16). 2. A circadian rhythm in the catecholamine content was found in the hypothalamus. CA content was lower by night than by day. 3. A longer light day (summer period) caused the shifting of rhythm phase in CA content. 4. Sex of eels does not affect CA content in the hypothalamus.
D000811:Anguilla / Q000378:metabolism*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D002940:Circadian Rhythm; D005260:Female; D006651:Histocytochemistry; D007031:Hypothalamus / Q000378:metabolism*; D008297:Male; D008856:Microscopy, Fluorescence; D012621:Seasons
D002395:Catecholamines