title: Pituitary anatomy and physiology.
abstract: The pituitary has been called the master gland of the body because of its central role in governing homeostasis, maintaining the reproductive cycle, and directing the activity of other glands. Housed in the sella turcica of the sphenoid bone at the base of the skull, it has important anatomic relations with the hypothalamus, visual pathways, cavernous sinus, carotid artery, and cranial nerves. The gland originates from two discrete parts of the developing embryo. Rathke's pouch, a dorsal evagination of the stomodeum, forms the anterior and intermediate lobes. The infundibulum, a ventral extension of the diencephalon, forms the posterior lobe. The anterior, intermediate, and posterior lobes of the pituitary gland function as three separate endocrine organs, each characterized by distinct cell populations, secretory products, and regulatory mechanisms. The anterior lobe secretes thyroid stimulating hormone, corticotropin, luteinizing hormone, follicle stimulating hormone, growth hormone, and prolactin. It is regulated by the hypothalamus via the portal vascular system. The posterior lobe releases oxytocin and vasopressin from axon terminals that originate in cell bodies located in the hypothalamus. The intermediate lobe is rudimentary in human beings but produces several hormones whose physiologic significance is only now being established.
authors.affiliation: Department of Neurological Surgery, Keck School of Medicine, University of Southern California, 1200 North State Street, Suite 5046, Los Angeles, CA 90033-1029, USA. amar@aya.yale.edu
authors.forename: Arun Paul
authors.initials: AP
authors.lastname: Amar
authors.forename: Martin H
authors.initials: MH
authors.lastname: Weiss
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D019382:Human Growth Hormone / Q000378:metabolism; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism; D010902:Pituitary Gland / Q000033:anatomy & histology* / Q000196:embryology / Q000502:physiology*; D011388:Prolactin / Q000378:metabolism; D013972:Thyrotropin / Q000378:metabolism; D014667:Vasopressins / Q000378:metabolism
chemical_list: D014667:Vasopressins; D019382:Human Growth Hormone; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin