title: Hydroxyurea interferes negatively with triglyceride measurement by a glycerol oxidase method.
abstract: Measured triglyceride concentrations were extremely low (less than 100 mg/L) in the serum of some patients who were receiving hydroxyurea for myeloproliferative diseases. The assay being used to quantify triglycerides was a "cascaded" enzymatic method involving (a) lipase, to generate glycerol from triglycerides; (b) glycerol oxidase, to convert glycerol to glyceraldehyde, with generation of hydrogen peroxide; and (c) peroxidase, which acts on the hydrogen peroxide with subsequent coupled generation of a red-violet quinone (reagent system used in the Technicon RA-1000). Hydroxyurea added to serum samples appeared to inhibit the action of glycerol oxidase, with a stoichiometric relation to the concentration of substrate (a decrease of roughly 2.4 mmol/L in measured triglyceride per 1 mmol of hydroxyurea per liter). A different enzymatic assay for triglycerides, which involves glycerol kinase (Beckman Instruments) did not show this effect of hydroxyurea.
mesh_terms: D001322:Autoanalysis; D004305:Dose-Response Relationship, Drug; D005188:False Negative Reactions; D005985:Glyceraldehyde / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D006918:Hydroxyurea; D007700:Kinetics; D008049:Lipase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D013401:Sugar Alcohol Dehydrogenases / Q000378:metabolism*; D013997:Time Factors; D014280:Triglycerides / Q000097:blood*
chemical_list: D014280:Triglycerides; D005985:Glyceraldehyde; D006861:Hydrogen Peroxide; D013401:Sugar Alcohol Dehydrogenases; C036131:glycerol oxidase; D010544:Peroxidases; D008049:Lipase; D006918:Hydroxyurea