Neurohumoral control of the pineal gland. A model for the study of neuroendocrine integrative processes

This article discusses the experimental evidence which suggests that the pineal gland and its innervating neurons are useful paradigms for the study of neuroendocrine integrative processes. The obtained results can be summarized as follows: 1) existence of putative receptors for various hormones (estradiol, testosterone, 5α-dihydrotestosterone, progesterone, prolactin) in the mammalian pineal gland; (2) steroid metabolic pattern in the pineal gland resembling other brain areas involved in gonadotrophic regulation; (3) control of pineal estrophilic and androphilic receptors by adrenergic transmitter through β-adrenergic receptors and at a translational level; (4) denervation supersensitivity of hormone receptors to neurotransmitter; (5) modification of neuronal activity by hormone treatment at ganglionic and preganglionic sites of action; (6) estrophilic binding sites in ganglia; (7) correlation of pineal responsiveness to hormones with activity of sympathetic nerves; (8) modification by hormones of pineal β-adrenergic mechanisms (9) dissociation of hormone effects on the pineal gland in those mediated or modulated by changes in afferent neuronal activity and those relatively unaffected by denervation. Collectively these data indicate that neuroendocrine, endocrine-neural and endocrine-endocrine transducing processes occur in the pinealocytes and superior cervical ganglia.