AJP - Heart and Circulatory Physiology, Vol 242, Issue 4 496-H499, Copyright © 1982 by American Physiological Society
Vasopressin in brain of spontaneously hypertensive rats
W. Rascher, R. E. Lang, T. Unger, D. Ganten and F. Gross
In stroke-prone spontaneously hypertensive rats (SHRSP) and in normotensive
Wistar-Kyoto rats (WKY), arginine vasopressin (AVP) was measured by means
of a radioimmunoassay in the plasma, the pituitary gland, the hypothalamus,
and the brain stem. In 6- and 14-wk-old SHRSP, the plasma concentration of
AVP was lower than in age-matched WKY (P less than 0.01), whereas it was
elevated at 28 wk of age (P less than 0.01). In the pituitary of 6-wk-old
SHRSP, AVP was higher than in WKY (P less than 0.05), but no such
difference was found in older rats. In the hypothalamus and the brain stem,
AVP content was reduced in all age groups of SHRSP. Plasma osmolality was
diminished in 28-wk-old SHRSP only (P less than 0.01), whereas hematocrit
in all age groups was higher in SHRSP than in WKY. It is concluded that the
secretion of AVP and possibly its synthesis in the hypothalamus are reduced
in SHRSP. Whether the reduced AVP content in the brain stem is related to
the sustained elevation of blood pressure has to be studied further.
