Effects of sham-pinealectomy, performed under white and red light, on the melatonin content of rat pineal glands.

Sham-pinealectomy, performed under different light conditons in newborn and adult rats, is followed by changes of pineal activity resulting in variations of melatonin content. The pineal glands of rats sham-operated under white light produce significantly less melatonin. In contrast, glands of rats operated on under red light show a melatonin content corresponding to that of intact rats. This result implies that normal white light causes a disturbance in melatonin production by a non-retinal pathway.