Pituitary Gland
A small endocrine gland at the base of the brain that produces and secretes several critical hormones including growth hormone, LH, FSH, ACTH, and TSH. The pituitary also stores oxytocin and vasopressin. Many peptide drugs directly target pituitary function or treat pituitary disorders.
Technical Context
The pituitary weighs approximately 0.5g and sits in the sella turcica of the sphenoid bone, connected to the hypothalamus by the pituitary stalk (infundibulum). The anterior lobe contains five major cell types: somatotrophs (GH, ~50%), lactotrophs (prolactin, ~20%), corticotrophs (ACTH, ~15%), gonadotrophs (LH/FSH, ~10%), and thyrotrophs (TSH, ~5%). Each cell type responds to specific hypothalamic releasing hormones. Pituitary adenomas (benign tumours) can oversecrete hormones — GH-producing adenomas cause acromegaly (treated with somatostatin analogues), ACTH-producing adenomas cause Cushing's disease (treated with pasireotide), and prolactinomas cause hyperprolactinaemia. Hypopituitarism (underfunction) may require replacement of multiple hormones including GH (somatropin).