dimethylarginine and Endotoxemia

The effect of taurine on the plasma levels of L-arginine, asymmetrical dimethylarginine (ADMA) and L-arginine/ADMA ratio and nitric oxide was investigated in experimental endotoxemia. L-arginine and ADMA levels were quantified by high performance liquid chromatography with fluorescence detector. Nitric oxide level was measured with spectrophotometric method. All experiments were performed with four groups (control, taurine, endotoxemia, taurine plus endotoxin) of 10 guinea pigs. After the endotoxin was administrated (4 mg/kg) ADMA level increased, nitric oxide level did not change but L-arginine level and L-arginine/ADMA ratio decreased. When taurine was administrated (300 mg/kg) no effect on ADMA and nitric oxide levels was observed compared to the endotoxemia group. But it was increased the L-arginine/ADMA ratio. Taurine may offer an advantage in because of it increases the reduced L-arginine/ADMA ratio.

Topics: Animals; Arginine; Endotoxemia; Endotoxins; Guinea Pigs; Male; Models, Animal; Nitric Oxide; Taurine

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) synthase enzymes, whereas symmetric dimethylarginine (SDMA) competes with arginine transport. Although both dimethylarginines may be important regulators of the arginine-NO pathway, their metabolism is largely unknown. In previous studies, evidence was found for the liver in the metabolism of dimethylarginines. We aimed to investigate dimethylarginine handling of the gut and the liver in detail under basal conditions and during endotoxemia.. Twenty-one male Wistar rats were used for this study. Endotoxemia was induced by lipopolysaccharide (LPS) infusion (8 mg/kg). Blood flow was measured using radiolabeled microspheres according to the reference sample method. Concentration of dimethylarginines were measured by high-performance liquid chromatography. The combination of arteriovenous concentration difference and organ blood flow allowed calculation of net organ fluxes and fractional extraction (FE) rates.. Arterial plasma concentration of ADMA was lower in LPS rats, in contrast to a higher SDMA concentration. For the gut, net release of ADMA was found, which was higher in LPS rats. In contrast, for the gut, net uptake of SDMA was found, which was lower in LPS rats. For the liver, a high net uptake of ADMA was found in both groups, while FE was significantly increased in LPS rats. Hepatic handling of SDMA was negligible.. The liver plays an important role in eliminating ADMA from the circulation and endotoxemia stimulates this capacity. In contrast to the liver, the gut releases ADMA. Endotoxemia results in a reduced systemic ADMA concentration.

Topics: Animals; Arginine; Disease Models, Animal; Endotoxemia; Gastrointestinal Tract; Lipopolysaccharides; Liver; Male; Rats; Rats, Wistar; Regional Blood Flow; Splanchnic Circulation; Viscera