[The circadian dynamics of the biochemical activity of the epiphysis in silver foxes]

Specific features of light-dependent biosynthesis of melatonin in the epiphysis are analyzed in female silver-black foxes. Just as in most previously studied animals, the serotonin and 5-hydroxyindolylacetic acid content of epiphysis decreased during the dark time of the 24 h period, while the activity of the melatonin-synthesizing enzyme N-acetyltransferase and melatonin content of epiphysis and plasma, on the contrary, markedly and reliably increased. However, the pattern of changes in the neurotransmitters dopamine and noradrenaline shows specific features.