Genetic and age-related differences in melatonin rhythms between the pineal organ and retina in bony fish

Complete melatonin rhythm generating systems are located within individual photoreceptor cells in the pineal organ and retina of Teleost fish.

• Both the pineal organ and retina respond to light, regulating daily variations in melatonin secretion.
• The activity of arylalkylamine N-acetyltransferase (AANAT) is controlled by light in these organs.
• Significant differences exist between the pineal organ and retina regarding the genes for photopigments and AANAT.
• The times of day when AANAT activity and melatonin production peak vary between these two sites.
• Developmental schedules for melatonin production may also differ between the pineal organ and retina.

Simplified