AJP - Renal Physiology, Vol 248, Issue 6 757-F761, Copyright © 1985 by American Physiological Society
Kinin stimulation of renin release in isolated rat glomeruli
W. H. Beierwaltes, J. Prada and O. A. Carretero
Numerous studies have suggested that a functional relationship exists
between the renal kallikrein-kinin and renin-angiotensin systems. We used
an in vitro preparation of isolated glomeruli to study the effect of kinins
on renin release. Glomeruli were harvested from the dissected cortices of
rat kidneys by a passive sieving technique. They were then placed in
chambers and superfused with aerated modified Krebs buffer, and the chamber
effluent was collected during two sequential 10-min periods. Bradykinin at
10(-6) M increased renin release from 2.17 +/- 0.34 to 4.05 +/- 0.72 ng ANG
I/min, and 10(-5) M bradykinin increased renin release from 3.51 +/- 0.64
to 8.94 +/- 1.27 ng ANG I/min. With albumin-modified buffer, 10(-5) M
bradykinin stimulated renin release from 7.11 +/- 0.79 to 14.03 +/- 2.36
ng/min. Lys-bradykinin at 10(-5) M also increased renin release from 5.69
+/- 1.11 to 14.50 +/- 2.65 ng ANG I/min. However, neither of the inactive
kinin analogues, [Tyr8]bradykinin or des-Arg9-bradykinin, had any effect on
renin release. We found that isolated glomeruli were relatively free of
kininase activity, in contrast to the high activity found in the kidney
slice preparation or in rat plasma. These results suggest that biologically
active kinins can stimulate renin release in an in vitro preparation that
is free of degradative kininases and independent of hemodynamic and neural
influences.
