1) The circadian rhythm persisted after pinealectomy , but disappeared after constant light exposure. (2) The response of SCN neurons to MEL was mainly inhibitory.

2) Objective To investigate the effect of pinealectomy on the reproductive functions of young rats.

3) Constant light and pinealectomy can destroy the function of circadian rhythm system.

4) Objective To explore the effect of pinealectomy on content of cerebral neurotic lipofuscin in aged rats.

5) This experiment is intended to elucidate the effect of pinealectomy on the secretion of vasopressin(VP) and oxytocin(OXT) in hypothalamic-neurohypophysis system.

6) Serum thyroid hormone level increased significantly on the 1st and 10th day after pinealectomy.

7) Methods Yong SD rats were randomly divided into sham operation group, pinealectomy group and melatonin administration group.