Melatonin rhythms in the eyes, pineal bodies, and blood of Japanese quail (Coturnix coturnix japonica)

Melatonin levels in the eyes, pineal bodies, and blood of Japanese quail show robust daily rhythms, with high levels at night and low levels during the day.

• Blood melatonin rhythms persisted in blinded and pinealectomized birds, with nighttime levels reduced by 33% and 54%, respectively, compared to control quail.
• A small melatonin rhythm remained in the blood of pinealectomized, blinded quail, indicating potential contributions from other sources.
• Blinding did not significantly affect melatonin levels in the pineal bodies, nor did pinealectomy impact ocular melatonin levels.
• Daily rhythms in melatonin content occur in the pineal bodies, the eyes, and the blood of quail.
• The blood melatonin rhythm results from secretion by both the pineal body and the eyes.

AI simplified