POSTERIOR PITUITARY HORMONES Flashcards
An extension of the forebrain and represents the storage region for vasopressin (also called ADH) and oxytocin.
Posterior pituitary
Synthesis of each of these hormones is tightly linked to the production of
Neurophysin
Is a cyclic nonapeptide, with a disulfide bridge connecting amino acid residues 1 and 6.
Oxytocin
Has a critical role in lactation100 and likely plays a major role in labor and parturition.
Oxytocin
Used in obstetrics to induce labor. Recent studies have linked oxytocin to maternal nurturing behavior and mother–infant bonding.
Pitocin
Structurally similar to oxytocin, cyclic nonapeptide with an identical disulfide bridge; it differs from oxytocin by only two amino acids
Vasopressin
Vasopressin’s major function
Regulate renal free water excretion (central role in water balance)
Where do vasopressin receptors can be found?
Renal collecting tubules and the ascending limb of the loop of Henle
Vasopressin are coupled with
Adenylate Cyclase
When vasopressin is activated, they induce insertion of
Aquaporin-2
Vasopressin is also a potent pressor agent and effects blood clotting104 by promoting
Factor VII release from hepatocytes and VwF release from endothelium
Vasopressin receptors (V1a and V1b) are coupled to
Phospholipase C
Osmoreceptors are extremely sensitive to even small changes in plasma osmolality, with an average osmotic threshold for vasopressin release in humans of
284 mOsm/kg
Initiate vasopressin release in response to a fall in blood volume or blood pressure.
Vascular Baroreceptors
Characterized by copious production of urine (polyuria) and intense thirst (polydipsia), is a consequence of vasopressin deficiency.
Diabetes Insipidus
