Neuroendocrinology of the Hypothalamus and Pituitary Axes

Abstract

The hypothalamus and pituitary gland which are, respectively, the approximate sizes of an almond and a bean seed form an integral part of the interface between the endocrine system and the central nervous system. The hypothalamus in addition is central in coordinating various metabolic, autonomic, and behavioral responses to environmental stimuli. These effects are mediated to less degree by neuronal connections with the rest of the brain and more so via the synthesis and secretion of myriad neurohormones which include stimulatory (releasing) and inhibitory hormones. These hormones and the secondary humoral factors whose secretion they modulate have central roles in the homeostatic control of processes as diverse as hunger, appetite, energy balance, temperature control, sleep regulation, other circadian rhythms, reproductive function, and social behavioral activities including affection and aggression. This chapter highlights the neuroendocrine functional relationships of the hypothalamic and pituitary axes to the rest of human systemic function.