Neuroendocrine control of appetite and metabolism

Abstract

Body homeostasis is predominantly controlled by hormones secreted by endocrine organs. The central nervous system contains several important endocrine structures, including the hypothalamic-pituitary axis. Conventionally, neurohormones released by the hypothalamus and the pituitary gland (hypophysis) have received much attention owing to the unique functions of the end hormones released by their target peripheral organs (e.g., glucocorticoids released by the adrenal glands). Recent advances in mouse genetics have revealed several important metabolic functions of hypothalamic neurohormone-expressing cells, many of which are not readily explained by the action of the corresponding classical downstream hormones. Notably, the newly identified functions are better explained by the action of conventional neurotransmitters (e.g., glutamate and GABA) that constitute a neuronal circuit. In this review, we discuss the regulation of appetite and metabolism by hypothalamic neurohormone-expressing cells, with a focus on the distinct contributions of neurohormones and neurotransmitters released by these neurons.

Fig. 1. Hypothalamic neuroendocrine cells and hormones.

Hypothalamic neuroendocrine cells regulate the adenohypophysis via the HP axis and the neurohypophysis through their axons. Note that the axons of the OXT and VP neurons constitute the neurohypophysis. The axons of other hypothalamic neurons are not shown for clarity. See the text for abbreviations.