AJP - Regulatory, Integrative and Comparative Physiology, Vol 249, Issue 6 726-R731, Copyright © 1985 by American Physiological Society
Hemorrhage in DOC-salt hypertensive rats: plasma and platelet vasopressin
J. T. Crofton, L. Share and D. P. Brooks
The effect of two consecutive hemorrhages, each 10% of blood volume, on
plasma vasopressin concentrations was determined in conscious unilaterally
nephrectomized Long-Evans rats made hypertensive by treatment for 3 wk with
deoxycorticosterone (DOC) and substitution of 1% saline for drinking water
(DOC-salt rats) or DOC alone (DOC rats) and in normotensive unilaterally
nephrectomized rats drinking water (H2O rats) or saline (NaCl rats). In
response to 20% hemorrhage, blood pressure decreased more (P less than
0.01) and plasma vasopressin increased less (P less than 0.01) in the
DOC-salt rats than in the other groups. Under basal conditions,
immunoreactive vasopressin was found in the platelets in NaCl, DOC, and
DOC-salt rats (P less than 0.01) but not in H2O rats. Platelet vasopressin
increased (P less than 0.05-0.01) in response to hemorrhage only in
DOC-salt rats. In conclusion, the vasopressin response to hemorrhage in
DOC-salt rats is impaired; platelet immunoreactive vasopressin is of little
importance in normal rats but is increased by treatment with DOC and/or
chronic salt loading; and platelet vasopressin increased in response to
hemorrhage only in DOC-salt rats.
