Published online by Cambridge University Press: 13 June 2014
Apart from well known areas of overlap between endocrinology and psychiatry (e.g. studies, in psychiatric disorders, of neurohormones and of the response to manipulations of hypothalamic-pituitary-target gland axis, and analysis of behavioural and psychological disturbances in endocrinological disorders) there is a more intimate intrinsic relationship between the brain and the endocrine system which is less well known or studied. Many of the extracranial endocrine glands have autonomic innervation. Like the pituitary gland which is under direct neural (as well as humoral) diencephalic control, the extracranial endocrine glands are under direct neural control, integrated by the hypothalamus and “head ganglion of the autonomic nervous system”. Yet it is only in the case of the pancreatic islets that this integration has been clearly defined. It is postulated that by this innervation the somatic endocrine glands can respond to homeostatic needs with a rapid initial secretion before the more sustained outpouring of humoral agents typically regulated by blood-borne constituents including pituitary hormones. This is a vast area awaiting further investigation.