[The melatonin content of the tissues of relatively wild and domesticated silver foxes Vulpes fulvus].

Pineal, plasma and retina melatonin content and its diurnal dynamics have been studied in adult relatively wild and domesticated female silver foxes. Diurnal cyclicity of melatonin concentration in these tissues was observed with a minimum during the day time, maximum in the middle of the night and intermediate level in the evening. Circadian melatonin dynamics was pronounced in non-domesticated as much as in domesticated females. However, since the pineal mass in domesticated animals is significantly smaller than in wild ones, the quantity of the hormone per 1 mg of the pineal tissue at night was much higher in the former. At the same time, plasma concentration of melatonin in both groups was the same. A possible cause of higher melatonin concentration in the pineal organ of domesticated foxes is discussed.