[3H]AVP binding to rat renal tubular receptors during long-term treatment with an antagonist of arginine vasopressin

Mah, S. C. and Whitebread, S. E. and De Gasparo, M. and Hofbauer, K. G.. (1988) [3H]AVP binding to rat renal tubular receptors during long-term treatment with an antagonist of arginine vasopressin. Peptides, Vol. 9, H. 3. pp. 595-600.

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Official URL: http://edoc.unibas.ch/dok/A5258633

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The interaction of an antagonist of arginine vasopressin (AVP), d(CH2)5-D-Tyr(Et)VAVP, with renal tubular V2 receptors were studied in medullary membrane preparations from kidneys of Sprague-Dawley and Brattleboro rats. In both rat strains, V2 receptors had comparable KD and Bmax values for binding of [3H]AVP. In vitro studies revealed that the V2-antagonist was more potent than cold AVP in displacing [3H]AVP. In vivo treatment of Sprague-Dawley rats with the antagonist over one week resulted only in a transient state of diabetes insipidus (DI). No specific [3H]AVP binding was detectable throughout the period of administration. Chronic treatment of Brattleboro rats resulted in a complete normalization of water intake. This agonistic effect was also associated with undetectable [3H]AVP binding. After stopping the infusion of d(CH2)5-D-Tyr(Et)VAVP, Bmax values tended to rise but had still not reached base line values after 6 days. In contrast, the chronic infusion of AVP in Brattleboro rats resulted in a reduction in water intake which was accompanied by a decreased Bmax. [3H]AVP binding remained detectable during the entire treatment period. Thereafter Bmax was restored to base line values within 2 days of stopping the infusion. These results suggest that d(CH2)5-D-Tyr(Et)VAVP has a high affinity for V2 receptors in both Sprague-Dawley and Brattleboro rats. Its rate of dissociation from the receptor appears to be much slower than that of AVP. In Brattleboro rats, the binding of d(CH2)5-D-Tyr(Et)VAVP leads to an antidiuretic response. In Sprague-Dawley rats, a transient diuretic response is followed by a progressive normalization in water intake. This occurs despite persistent and complete blockade of renal medullary V2 receptors.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Pharmacology/Neurobiology (Hofbauer)
UniBasel Contributors:Hofbauer, Karl G.
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
Last Modified:22 Mar 2012 14:22
Deposited On:22 Mar 2012 13:31

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