Renal excretion of 8-oxo-7,8-dihydro-2 ′-deoxyguanosine: degradation rates of RNA and metabolic rate in humans

Abstract

Renally excreted 8-oxo-7,8-dihydro-2 ′-deoxyguanosine (oxo 8dG) is a potential marker of oxidative DNA damage by reactive oxygen species. Whole-body degradation rates of t- and rRNA are potential indicators of the resting metabolic rate (RMR). Excretion rates of oxo 8dG and degradation rates of t- and rRNA were determined in healthy non-smoking adults and children. RMR (indirect calorimetry; 14 children, 16 adults), total energy expenditure (TEE; doubly labelled water technique; 4 children, 6 adults), and lean body mass (LBM; dual-energy X-ray absorptiometry; 14 children, 16 adults) were also measured. Degradation of t- and rRNA (μmol/d/kg LBM; 4 children, 6 adults) was highly correlated with RMR (kJ/d/kg LBM), r=0.867 ( p<0.005) and 0.959 ( p<0.001), respectively. Excretion of oxo 8dG (pmol/d/kg LBM; 14 children, 16 adults) was not significantly correlated with RMR ( p>0.05). Neither excretion of oxo 8dG nor degradation of RNA was significantly correlated with TEE (kJ/d/ kg LBM) ( p>0.05). In healthy subjects further factors, other than the metabolic rate, seem to influence the excretion rate of oxo 8dG. The degradation rates of t- and rRNA seem to be appropriate indicators of the RMR.