DISORDERS OF THE POSTERIOR PITUITARY
The posterior lobe of the pituitary gland (neurohypophysis) is an anatomical extension of the hypothalamus, containing the axons and axon terminals of neurons whose nuclei originate in the supraoptic and paraventricular areas of the hypothalamus. Two peptide hormones, arginine vasopressin and oxytocin, and their carrier proteins, the neurophysins, are synthesized in the cell bodies of these neurons. These peptides and their carrier proteins travel down the axons to the nerve terminals from which they are released in response to a variety of physiological stimuli.
Oxytocin causes release of breast milk and may promote uterine contractions during labor. There is no known function for this peptide hormone in men. Arginine vasopressin (also known as antidiuretic hormone [ADH]) is the principal hormonal factor regulating water metabolism. Deficiency of ADH or impaired action in its major target organ, the kidney, results in a polyuric state known as diabetes insipidus. Excessive and physiologically inappropriate secretion of ADH results in hyponatremia (the syndrome of inappropriate ADH secretion), as discussed elsewhere in this volume . Arginine vasopressin, as the name implies, also has pressor activity, the physiological relevance of which is unknown.
- PITUITARY NEOPLASMS: GENERAL CONSIDERATIONS
- HYPERPROLACTINEMIA: GALACTORRHEA-AMENORRHEA SYNDROME - Etiology
- SYNDROMES OF ANTERIOR PITUITARY HYPERFUNCTION: THE PITUITARY ADENOMA
- DISORDERS OF THE POSTERIOR PITUITARY
- HYPERPROLACTINEMIA: GALACTORRHEA-AMENORRHEA SYNDROME - Treatment
- HYPERPROLACTINEMIA: GALACTORRHEA-AMENORRHEA SYNDROME - Clinical Manifestations
- HYPERPROLACTINEMIA: GALACTORRHEA-AMENORRHEA SYNDROME - Diagnosis
- GIGANTISM AND ACROMEGALY - Treatment
- GIGANTISM AND ACROMEGALY - Diagnosis
- GIGANTISM AND ACROMEGALY