In bile duct ligated rats, arginase (ASE) release from damaged hepatocytes
results in low arginine (ARG) levels despite maximal renal ARG production.
Plasma ARG levels were restored by reducing gut-derived endotoxemia that lo
wered circulating ASE activity although maintaining increased renal product
ion. From this it was not clear if the higher renal ARG production was indu
ced by the low grade endotoxemia or the low arginine plasma levels, The sep
arate and combined influence of both factors on ARG metabolism was studied
in the rat. Male Wistar rats received either bovine liver ASE, to lower ARG
levels, or saline (SAL), Following the ASE or SAL infusion, rats were rand
omized to receive a low dose endotoxin (LPS) or SAL infusion, In ASE/SAL- a
nd ASE/LPS-treated rats, ARG levels were lower compared with SAL/SAL(p < .0
05) and SAL/LPS (p < .005). The increased ARG production by the kidneys and
gut proved to be independent of LPS but related to reduced ARG plasma leve
ls (both p < .05 when compared with SAL/SAL and SAL/LPS). Metabolism of rel
ated amino acids was not explanatory. The study concluded that a low grade
endotoxemia did not influence the metabolism of ARG by the gut, kidney, and
liver. Reductions in ARG plasma by ASE treatment, irrespective a low dose
endotoxin, were the drive for ARG production by the gut and the kidney.