AJP - Heart and Circulatory Physiology, Vol 246, Issue 3 404-H409, Copyright © 1984 by American Physiological Society
Comparison of renin-specific IgG and antibody fragments in studies of blood pressure regulation
V. J. Dzau, R. I. Kopelman, A. C. Barger and E. Haber
The use of antirenin antibody and its fragments as specific tools for the
analysis of the role of renin in blood pressure regulation is assessed in
this study. Specific immunoglobulin G (IgG) or its antibody fragments (Fab)
raised against purified canine renal renin were employed. These agents had
no effect on blood pressure in the sodium-replete unanesthetized dog but
induced systemic vasodepressor response (16.4 +/- 2 mmHg mean pressure) and
suppression of plasma renin activity in sodium-deplete animals.
Renin-specific IgG or Fab restored mean systemic pressure of acute
renovascular hypertensive dogs to normotensive levels (132 +/- 2 to 90 +/-
5 mmHg) associated with inhibition of plasma renin activity (11.2 +/- 2 to
1.4 +/- 0.7 ng angiotension I X ml-1 X h-1). A linear relationship was
demonstrated between the reduction in mean systemic pressure and fall in
plasma renin activity (r = 0.87, P less than 0.005). The onset of action of
both agents occurred within minutes. However, the peak effect of Fab was
observed within 1-2 min, while that of IgG was delayed by approximately 20
min. The duration of action of Fab was short lived (about 30 min) whereas
that for IgG was prolonged (up to 24 h). The results demonstrate the
usefulness of renin-specific IgG and Fab as tools in physiological studies.
