AJP - Regulatory, Integrative and Comparative Physiology, Vol 249, Issue 3 313-R316, Copyright © 1985 by American Physiological Society
Platelet and plasma vasopressin in dog during hydration and vasopressin infusion
L. Share, J. T. Crofton, D. P. Brooks and C. M. Chesney
Dog platelets contain a substance immunologically similar to arginine
vasopressin. In conscious and anesthetized dogs under basal conditions,
platelet immunoreactive vasopressin accounts for approximately 40% of the
total circulating immunoreactive vasopressin. When the plasma vasopressin
concentration in the anesthetized dog was lowered 75% by intravenous
infusion of isotonic dextrose solution for 2 h, the platelets failed to
discharge a significant quantity of immunoreactive vasopressin.
Subsequently, when the plasma vasopressin concentration was elevated to a
level 10-fold greater than the initial levels by intravenous infusion of
arginine vasopressin, there was no statistically significant increase in
the estimated platelet vasopressin content measured 1 and 2 h after the
start of the infusion, although there was the suggestion that the platelets
had indeed taken up some vasopressin after 2 h of vasopressin infusion.
Thus immunoreactive vasopressin in dog platelets does not appear to
exchange readily with plasma vasopressin. The physiological role of
platelet immunoreactive vasopressin remains to be determined.
