Dopamine and serotonin in the trout (Oncorhynchus mykiss) pituitary: main metabolites and changes during gonadal recrudescence.
Monoamine neurotransmitters and their metabolites in the trout pituitary have been studied. Dopamine (DA), serotonin (5HT), dihydroxyphenylacetic acid (DOPAC), and 5-hydroxyindoleacetic acid (5HIAA) were separated as pure peaks by HPLC. Peak purity and identity were confirmed by electrochemical behavior. However, measurable amounts of the O-methylated DA metabolites 3-methoxytyramine and homovanillic acid were not detected in pituitary glands of different-aged trout or during the reproductive cycle. Treatment with L-DOPA or DA increased DOPAC levels, whereas O-methylated DA metabolites remained undetectable. Thus, MAO may be the major, if not the only, enzyme involved in DA catabolism in trout pituitary. A pronounced decline in dopaminergic turnover, measured as the DOPAC/DA ratio, was seen as gonadal recrudescence developed. 5HT or 5HIAA levels were not associated with reproductive status.
Hernandez-Rauda
R
R
Dpto. de Fisioloxía, Facultade de Bioloxía, Universidade de Santiago de Compostela, Galicia, Spain.
Otero
J
J
Rey
P
P
Rozas
G
G
Aldegunde
M
M
D000818:Animals; D002118:Calcium / Q000097:blood / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004298:Dopamine / Q000378:metabolism*; D004563:Electrochemistry; D005260:Female; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D010053:Ovary / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D010902:Pituitary Gland / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D012098:Reproduction / Q000502:physiology; D012701:Serotonin / Q000378:metabolism*
D011506:Proteins; D012701:Serotonin; D002118:Calcium; D004298:Dopamine