AJP - Regulatory, Integrative and Comparative Physiology, Vol 234, Issue 3 98-103, Copyright © 1978 by American Physiological Society
Arterial pressure-urinary output relationship in hypertensive rats
R. A. Norman Jr, J. A. Enobakhare, J. W. DeClue, B. H. Douglas and A. C. Guyton
The steady-state relationship between mean arterial pressure (AP) and
output of sodium and water was determined for one-kidney control (1KC),
one-kidney Goldblatt (1KG), normotensive Wistar-Kyoto (WKY), and Okamoto
spontaneously hypertensive rats (SHR). Control fluid intake (given by
intravenous infusion) was set at approximately 30 ml/day Ringer solution.
The infusion rate was then increased progressively to 2, 4, and 8 times
control for 24- to 48-h periods each. Control AP averaged 115 Torr in 1KC,
152 Torr in 1KG, 120 Torr in WKY, and 158 Torr in SHR. The eightfold
increase in salt and water intake was accompanied by almost equal increase
in salt and water output and increases in AP to 157 Torr in 1KC, 190 Torr
in 1KG, 126 Torr in WKY, and 166 Torr in SHR. The arterial pressure-urinary
output relationship in 1KG is parallel to that of 1KC but shifted to higher
AP levels. Similarly, this relationship in SHR is parallel to that of WKY
but shifted to higher AP levels. This parallel shift is indicative of
uniform renal vasoconstriction but normal functional renal mass in the SHR.
