AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 4 487-R491, Copyright © 1983 by American Physiological Society
Suppressed basal antidiuretic hormone release during cyclooxygenase inhibition in conscious dogs
B. R. Walker
Both in vitro and in vivo experiments suggest that prostaglandins may
affect antidiuretic hormone (ADH) release centrally. In addition, other
studies show that prostaglandins administered peripherally may cause ADH
release. However, these latter studies have been flawed by hemodynamic
alterations and the use of anesthetics, which make interpretation
difficult. The present study was designed to test for involvement of
prostaglandins produced outside the central nervous system in ADH release
in conscious dogs. Administration of meclofenamate (2 mg/kg and 2 mg X kg-1
X h 1, iv) resulted in a consistent fall in plasma ADH levels in five dogs.
This diminution of ADH release occurred with no change in systemic
hemodynamics, arterial blood gases, or plasma osmolality, suggesting that
prostaglandins are important mediators of basal ADH release in the
conscious dog. Because meclofenamate does not cross the blood-brain
barrier, prostaglandins produced outside the central nervous system appear
to be involved in this process. The specific prostaglandin involved or the
site of action of prostaglandins on ADH release is not clear at this time.
