Transcriptional Control of the Development and Function of the Hypothalamic-Pituitary Axis

The hypothalamic-pituitary (H-P) axis regulates many aspects of mammalian endocrine physiology by the controlled secretion of hormones. The hypothalamus is part of the diencephalon at the base of the brain beneath the third ventricle (1) . It is physically located posterior to the optic chiasm and rostral to the mammillary bodies. The pituitary gland (or hypophysis) is a small organ located beneath the hypothalamus that weighs about 0.5 g in humans (2) . The posterior pituitary lobe (or neurohypophysis or pars nervosa) develops directly from the brain ( see below) and is connected to the hypothalamus by the infundibulum (or pituitary stalk). The anterior lobe (or adenohypophysis or pars distalis) and intermediate lobe (or pars intermedia) of the pituitary have distinct embryological origins. In the mature gland, these structures are fused to the posterior pituitary, and some cells of the anterior pituitary proliferate up and around the pituitary stalk to form the pars tuberalis. The intermediate lobe is a poorly developed structure in adult humans and is absent in birds (2) . A vascular link called the portal system arises from the median eminence at the base of the hypothalamus and provides a connection for the passage of neurosecretory hormones from the hypothalamus to the anterior pituitary gland. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.