Active renin and renin glycoform dynamics in the carotid
artery.
Katz, Stephen A., John A. Opsahl, Lynn M. Forbis, and Woubeshet
Ayenew.
Division of Nephrology, Hennepin County Medical Center, 55415-1829,
and Departments of Physiology and Medicine, University of Minnesota
Medical School, Minneapolis, Minnesota 55455
APStracts 2:0546H, 1995.
Rabbit active renin can be resolved into 5 major glycoforms (glycoform
profile) using high resolution isoelectric focusing. The least
negatively charged renin glycoforms (denoted as glycoforms I and II)
are preferentially stored in the kidney, preferentially secreted in
response to acute stimulation, and have the shortest plasma half
-lives. In the present study, we measured the concentration and
glycoform profile of active renin in plasma and the carotid wall of
anesthetized rabbits before and 1.5 and 24 hours after bilateral
nephrectomy (BNX). Carotid renin activity was verified to be due to
the enzymatic activity of renin, and plasma contamination of the
blood vessel wall was minimized. Prior to BNX, there was no
difference in renin glycoform proportions (expressed as a percentage
of the total active renin present) between plasma and the carotid
wall. One and one-half hours after BNX, plasma renin concentration
(PRC) fell by 67%, and plasma renin glycoforms I+II were
preferentially cleared from the plasma, but no significant change in
renin concentration was seen in the carotid artery (or aorta).
However, the proportion of renin glycoforms I+II in the carotid wall
increased significantly from 35% to 53%. Twenty four hours after BNX,
PRC and carotid wall renin concentrations were reduced by 99.7% and
97.7% respectively, while the proportion of renin glycoforms I+II in
the carotid wall were significantly elevated compared to pre-BNX and
1.5 hour BNX time points. However, the proportions of renin
glycoforms I+II in plasma did not fall as expected 24 hours after
BNX, despite the 99.7% reduction in PRC. These data are consistent
with the view that vascular renin is derived from plasma renin of
renal origin. The active renin found in the carotid wall is composed
of the same renin glycoforms as plasma active renin. After
nephrectomy, renin disappearance from the carotid (and aortic wall)
is slower than renin decay from plasma, and the less negatively
charged active renin glycoforms I+II appear to exit the carotid wall
much more slowly than the more negatively charged glycoforms. At the
24 hour BNX time point, renin glycoforms I+II were still slowly
effluxing from the vascular wall, (and perhaps other tissues), and
represented the only glycoforms present in the carotid wall.
Received 8 September 1995; accepted in final form 28 November
1995.
APS Manuscript Number H847-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95