Antidiuretic hormone agonists

The U2 agonists are associated with hyperglycemia, hypoinsulinemia and increased micturition (through antagonism of antidiuretic hormone) in adult horses but not in foals (Robertson et al 1990). The U2 agonist-induced hyperglycemia and h3 oinsulinemia result from inhibition of insulin release from the pancreatic islet (3 cells. 

DIABETES INSIPIDUS TREATMENT involves the administration of drugs to counteract the under-production of antidiuretic hormone (ADH vasopressin) by the pituitary gland, which is a characteristic of diabetes insipidus. ADH itself (arginine vasopressin or lysine vasopressin) can be used, as can the analogues desmopressin and terlipressin. These are all (V subtype) VASOPRESSIN RECEPTOR AGONISTS. These agents are discussed... 

Enhancement of diuretic hormone actions could be fatal for those insects that have critical problems of maintaining body water, esp. soft-bodied larvae. Soft-bodied larvae rely on hemolymph volume to maintain turgor for movement, and dehydration would result in immobility followed by death, inhibition of antidiuretic hormones could have serious effects on insects that reside in extremely dry environments, e.g. stored grain. Antidiuretic hormone antagonists in combination with diuretic hormone agonists would be especially potent. 

Opiate agonists mediate a decrease in renal perfusion. In addition, they stimulate the release of antidiuretic hormone (ADH). which results in an increase in urine output. 

B. Vasopressin (Antidiuretic Hormone, ADH) Vasopressin is synthesized in the supraoptic nuclei of the hypothalamus and released from the posterior pituitary. As discussed in Chapter 15, vasopressin acts on V2 receptors and increases the synthesis or insertion of water channels by a cAMP-dependent mechanism, resulting in an increase in water permeability in the collecting tubules of the kidney. The increased water permeability permits water reabsorption into the hypertonic renal papilla, thus causing the antidiuretic effect. Vasopressin also causes smooth muscle contraction (a V, effect). Desmopresan, a selective agonist of V2 receptors, is used in the treatment of pituitary diabetes insipidus. 

Desmopressin Antidiuretic hormone analog Pituitary diabetes insipidus A Vj receptor agonist longer-acting than vasopressin (ADH)... 

Either remifentanil or propofol could have been responsible in this case. Remi-fentanil is a pure p opioid receptor agonist, which inhibits vasopressin release from the posterior pituitary however, this patient had previously had a hypophysectomy. Propofol reversibly inhibits the action of antidiuretic hormone in rat hypothalamus, and this could have formed the basis of transient diabetes insipidus. 

Ornipressin is a selective agonist at vasopressin Vi receptors and has weaker antidiuretic activity than the native hormone. 

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