Nitrite plasma levels after an oral fat meal in normolipemic subjects.

BACKGROUND

The authors, investigating the effects of an oral triglyceride-rich fatty load upon the endothelial function as regards the production of nitric oxide, performed the determination of plasma nitrites, which are stable, specific and irreversible end-products of nitric oxide.

METHODS

The series consists of 13 metabolically normal female subjects (mean age 55 +/- 7 years); after an overnight fasting each subject undertook an oral fat load (butter 1 g/kg); a venous blood withdrawal was carried out before oral fat meal and after two and four hours. For each plasma sample total cholesterol, HDL-cholesterol and triglyceride plasma levels were determined by enzymatic methods; LDL-cholesterol was calculated by Friedwald's formula; the nitrite plasma levels were obtained by the Gutman and Hollywood colorimetric method.

RESULTS

Total cholesterol, HDL-cholesterol, LDL-cholesterol did not show significant changes after the oral fat load; triglycerides rose significantly (p < 0.05) after 4 hours as compared to the basal value (226 +/- 12 vs 175 +/- 12 mg/dl, +30%). The nitrite plasma levels were almost unchanged before oral fat load and after 2 and 4 hours.

CONCLUSIONS

The results suggest that the acute biochemical stress consisting of increased triglyceride-rich very low density lipoproteins was not able to stimulate the endothelial production of nitric oxide.