Pituitary gland Rathke's pouch. This contrasts with the posterior pituitary, which originates from neuroectoderm. Endocrine cells of the anterior pituitary are controlled by regulatory hormones released by parvocellular neurosecretory cells in the hypothalamic capillaries leading to infundibular blood vessels, which in turn lead to a second capillary bed in the anterior pituitary. This vascular relationship constitutes the hypothalamo-hypophyseal portal system. Diffusing out of the second capillary bed, the hypothalamic releasing hormones then bind to anterior pituitary endocrine cells, upregulating or downregulating their release of hormones. The anterior lobe of the pituitary can be divided into the pars tuberalis (pars glandularis) and pars
Anterior pituitary death and can lead to gigantism, a hormone disorder shown in “giants” such as André the Giant, where it occurs before the epiphyseal plates in bones close in puberty. The most common type of pituitary tumour is a prolactinoma which hypersecretes prolactin. A third type of pituitary adenoma secretes excess ACTH, which in turn, causes an excess of cortisol to be secreted and is the cause of Cushing's disease. Hypopituitarism is characterized by a decreased secretion of hormones released by the anterior pituitary. For example, hypo-secretion of GH prior to puberty can be a cause of dwarfism. In addition, secondary