FLUOROMETRIC AND COLORIMETRIC ENZYMIC DETERMINATION OF TRIGLYCERIDES (TRIACYLGLYCEROLS) IN SERUM

  • 1 January 1980
    • journal article
    • research article
    • Vol. 26  (5) , 613-617
Abstract
Two fully enzymic methods, fluorometric and colorimetric were described for determination of triglycerides (triacylglycerols) in serum. Samples are incubated with microbial lipase for 10 min, and the glycerol released from the triglycerides is oxidized by NAD+ in the presence of glycerol dehydrogenase. In the fluorometric method the resulting NADH in turn oxidized by resazurin as catalyzed by diaphorase to form resorufin, a highly fluorescent compound. In the colorimetric method the NADH is oxidized by coupling with a tetrazolium salt/diaphorase system to form formazan, a highly colored compound. Calibration curves constructed by plotting change in fluoresence or absorbance vs. concentration of triglycerides were linear up to 6 and 5 g of triglycerides/l of serum for the fluorometric and colorimetric methods, respectively. The assays require only 5 and 15 .mu.l of serum for fluorometry and colorimetry, respectively. The CV was 0.59% for the fluorometric method and 0.91% for the colorimetric procedure. The time for analysis for either method is less than 15 min. The results correlate well with those obtained by the Dow Diagnostic Kit method, a colorimetric method in which glycerol kinase and glycerol-1-phosphate dehydrogenase form NADH from ATP and NAD+ in the presence of glycerol and glycerol-1-phosphate.