Nitrite, endothelin and E-selectin plasma levels after arginine infusion in normal, obese and type 2 diabetic...

The authors studied the behaviour of nitrites (specific end-products of nitric oxide), endothelin and E-selectin after arginine infusion (biosynthetic precursor of nitric oxide).

The series consisted of 28 female subjects (mean age 59 +/- 8) of whom: 12 normal controls; 12 suffering from essential obesity (BMI 31.4 +/- 0.7); 14 suffering from uncomplicated type 2 diabetes mellitus. Each subject received intravenous arginine (20 g in two hours); before the infusion and after 1 hour and 2 hours venous blood withdrawal was performed. For each plasma sample the levels of nitrites (colorimetric reaction), endothelin (ELISA method) and E-selectin (ELISA method) were determined.

In the controls plasma nitrites decreased significantly (p < 0.05), more evidently at the second hour. In the obese subjects a sharp significant (p < 0.05) fall of nitrites was observed, more evidently at the second hour. In the diabetics nitrite values were reduced (p < 0.05) compared to the baseline. Endothelin levels after arginine were almost unchanged in normal and obese subjects, while in diabetics a significant (p < 0.05) reduction was observed. In the three groups of subjects E-selectin values were not modified by arginine.

This study demonstrates that arginine infusion increase NO biosynthesis in normal, obese and diabetic subjects, inducing a significant reduction of nitrites for an early process of organic reconversion; endothelin showed a reductive trend, mainly in diabetics, probably due to an antagonistic balanced response towards an overproduction of nitric oxide. E-selectin did not change, without correlation with the nitrite and endothelin values, because of an independence from the production of the two "hemodynamic markers".