DT-diaphorase in morbidly obese patients

Dicumarol sensitive DT-diaphorase (EC 1.6.99.2) activity has been measured in human cytosol from liver and various extrahepatic tissues not containing tumors which were removed during elective operations. The specific activity was found to be highest in tissues of the gastrointestinal tract. In contrast to rodent liver, the human liver has extremely low DT-diaphorase activity. Tissue activity was found to be highly variable among the patients studied which suggests that nutritional and/or genetic factors may be involved. The variability ranged from undetectable levels in liver to 223 nmol/mg X min in stomach. The data question whether the current concept concerning the biological function of this enzyme is applicable to man.