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Nitric oxide is now established as a biological mediator of clinical relevance. The present study investigated the production of nitric oxide by lympho-mononuclear leukocytes from alcoholic patients with either hepatitis or cirrhosis. The study included 42 patients, 12 without any liver disease and 30 alcoholic patients, 13 of whom had histologically confirmed cirrhosis and 17 alcoholic hepatitis. Cells were obtained from peripheral blood by density gradient and incubated in sterile conditions in RPMI 1640 for 6 h at 37 degrees C. Culture supernatants were assayed for nitrite concentration using the Griess reaction. Cells from cirrhotic but not from hepatopathic patients showed significantly higher nitrite production than controls (cirrhotic, 0.36 +/- 0.07; hepatopathic, 0.13 +/- 0.02; control: 0.25 +/- 0.05 nmol/10(6) cells/6 h). In cirrhotic patients L-Nitro-arginine methylester inhibited nitrite production (0.18 +/- 0.05). These data suggest that alcoholic cirrhotic but nonhepatopathic patients show an increased nitric oxide production by blood lymphomononuclear cells. This production could be involved in the systemic vasodilation in cirrhotic patients.

Gentamicin-induced acute renal failure is characterized by a decrease in renal plasma flow and creatinine clearance. Endothelins (ET) are potent renal vasoconstrictors. The aim of this work is to assess the role of ET-1 in gentamicin-induced renal failure. Renal glomerular release of ET-1 was measured in rats with gentamicin-induced nephrotoxicity (100 mg/kg/day, s.c. for 2, 4 or 6 days). Glomeruli were isolated and incubated for 24 h in RPMI-1640. Glomerular supernatant and plasma concentration of ET-1 were measured by RIA. Renal failure was assessed by insulin, para-aminohippuric and creatinine clearance and histological studies. Gentamicin induced a dose number-dependent increase in plasma creatinine and a decrease in creatinine clearance. This was accompanied by a marked decrease in inulin and para-aminohippuric acid clearance, as well as by a marked tubular necrosis, without alterations in glomerular structures. Plasma ET-1 concentration and glomerular ET-1 release were also increased in gentamicin-treated rats. When 10-5 M gentamicin was added to control glomeruli, ET-1 production was not modified (36.4 +/- 2.2 vs. 35.2 +/- 1.7 pg/ml/24 h). All these results suggest that elevated ET-1 plasma levels and increased glomerular release of ET-1 could mediate, at least in part, the decrease in glomerular filtration rate observed in gentamicin-induced ARF.

The present experiments were designed to assess the effect of inhibiting NO synthesis on the renal failure induced in rats by treatment with high doses of gentamicin. Eighteen Wistar rats were given gentamicin 100 mg/kg body weight/day for 5 days, whereas another 18 rats were used as control. Half of the gentamicin-treated rats and half of the controls also received the specific inhibitor of NO synthesis, N^G-nitro-L-arginine methyl ester (L-NAME), 0.05 mg/ml in the drinking water for 5 days. Arterial pressure and renal function were measured on the 5th day of the study. In the animals treated with L-NAME, arterial pressure was higher than in untreated rats, thus suggesting that the treatment was effective in inhibiting NO synthesis. Rats that received L-NAME and gentamicin, showed higher plasma creatinine levels and higher score of renal damage, as well as lower Na⁺ and K⁺ excretion and creatinine clearance than rats that received gentamicin alone. These data showing that NO inhibition aggravates gentamicin-induced renal failure, suggest that endogenously released NO plays a protective role in gentamicin nephrotoxicity.

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