Antidiuretic antagonism and agonism of 1-deamino-pentamethylene-2-D-phenylalanine-4-isoleucine-arginine vasopressin in rats with diabetes insipidus.
Using implanted minipumps it was shown over a period of 7 days that the vasopressin antagonist, 1-deamino-pentamethylene-2-D-Phe-4-Ile-arginine vasopressin, caused increased diuresis in normal rats and reversed vasopressin- or oxytocin-induced antidiuresis in Brattleboro rats. When the antagonist was infused alone in Brattleboro rats it induced a marked antidiuretic response, indicating that the analogue also possessed agonistic properties. The agonist action could not be demonstrated in anaesthetized, hydrated normal rats. In these animals the analogue behaved as a pure antagonist. It is concluded that analogues which behave as antagonists in one test model may display agonistic properties under different experimental conditions.
D000818:Animals; D001127:Arginine Vasopressin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D003919:Diabetes Insipidus / Q000503:physiopathology*; D004231:Diuresis / Q000187:drug effects*; D004357:Drug Synergism; D005260:Female; D007263:Infusions, Parenteral; D008297:Male; D009994:Osmolar Concentration; D010121:Oxytocin / Q000037:antagonists & inhibitors; D051381:Rats; D011919:Rats, Inbred Strains; D014556:Urine; D014667:Vasopressins / Q000037:antagonists & inhibitors*
D014667:Vasopressins; D001127:Arginine Vasopressin; D010121:Oxytocin; C051782:argipressin, 1-deaminopentamethylene-Phe(2)-Ile(4)-