AJP - Endocrinology and Metabolism, Vol 240, Issue 1 60-E64, Copyright © 1981 by American Physiological Society
Increased enzymatic activity of renin and hyperlipidemia
T. A. Kotchen and R. T. Talwalkar
We have previously reported that the in vitro enzymatic activity of
exogenous renin, plasma renin reactivity (PRR), is increased in plasma of
patients with chronic renal failure, possibly due to the deficiency of a
renin inhibitor. To determine whether increases PRR is related to renal
failure per se or to hyperlipidemia, PRR was measured in 10 control
subjects, 10 patients with renal failure, and 10 hyperlipidemic patients
with normal renal function. Compared to that in control subjects (52.6 ng
angiotensin I generated per ml/h +/- 3.8 SE) PRR was increased (P <
0.05) in plasma of uremic patients (65.1 +/- 4.3) and hyperlipidemic
patients (71.4 +/- 10.7). Renin substrate concentration did not differ
among groups, and after denaturation of endogenous substrate by
acidification of plasma, PRR was still increased. A "protein-free" extract
of plasma from normal subjects inhibited renin, whereas little or no
inhibition occurred with a comparable extract from uremic patients and
hyperlipidemic patients. Thus, alterations in lipid metabolism may account
for the increased enzymatic activity of renin in uremic plasma. Increased
PRR may be related to the deficiency of a normally occurring renin
inhibitor.
