Hypothalamus – releases TRH, CRH, GnRH, GHRH, and dopamine into median eminence; passes through neurohypophysis on way to adenohypophysis

  Dopamine – inhibits prolactin secretion

  Posterior pituitary (neurohypophysis)

•  ADH – supraoptic nuclei, regulated by osmolar receptors in hypothalamus

•  Oxytocin – paraventricular nuclei in hypothalamus

•  Neurohypophysis does not contain cell bodies

  Anterior pituitary (80% of gland, adenohypophysis)

•  Releases ACTH, TSH, GH, LH, FSH, and prolactin

•  Does not have its own direct blood supply; passes through neurohypophysis 1st (portal venous system)

  Bi-temporal hemianopia – pituitary mass compressing optic nerve (CN II) at chiasm

  Nonfunctional tumors – almost always macroadenomas; present with mass effect and decreased ACTH, TSH, GH, LH, FSH. Tx: transsphenoidal resection

  Contraindications to transsphenoidal approaches – suprasellar extension, massive lateral extension, dumbbell-shaped tumor

  Most pituitary tumors respond to bromocriptine (dopamine agonist)

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