The pineal organ in man. An endocrine gland awaiting recognition.

Information on pineal gland function in man is briefly reviewed. The evidence presented suggests that in man the pineal gland: (i) is involved in control of certain types of behaviour, such as sleep and sleepiness; (ii) is associated with direction orientation; (iii) is in some way related to the phenomenon known as jet lag; (iv) affects sexual maturation; and (v) may affect sperm motility. On the basis of available evidence it is concluded that in man the pineal gland must be regarded as an endocrine gland participating in the close synchronization of a variety of functions.