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 sta ble, specific and irreversible end-products of nitric oxide. Methods. The series consists of 13 metabolically normal female subjects (me an 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 be fore oral fat meal and after two and four hours. For each plasma sample tot al cholesterol, HDL-cholesterol and triglyceride plasma levels were determi ned by enzymatic methods; LDL-cholesterol was calculated by Friedwald's for mula; the nitrite plasma levels were obtained by the Gutman and Hollywood c olorimetric method. Results. Total cholesterol, HDL-cholesterol, LDL-cholesterol did not show s ignificant changes after the oral fat load; triglycerides rose significantl y (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 ora l fat load and after 2 and 4 hours. Conclusions. The results suggest that the acute biochemical stress consisti ng of increased triglyceride-rich very low density lipoproteins was not abl e to stimulate the endothelial production of nitric oxide.