Sex- or age-related differences were not detected in the activity of dihydropyrimidine dehydrogenase from rat liver

We examined the influence of ageing and gender on the activity of dihydropyrimidine dehydrogenase (DPD) in male and female Sprague-Dawley rats at 3, 8, 40 and older than 60 weeks of age. The body and liver weights of male rats at 8 weeks and older of age were heavier than those of female rats at the same age and the ratio of liver to body weight was significantly reduced with ageing. The amount of produced 5FU metabolites, dihydrofluorouracil and fluoroureidopropionic acid, remained unchanged in the reaction mixture with the cytosol from any group of the rats. The formation rates of 5FU metabolite were 1.03 ± 0.08 / 1.12 ± 0.06, 0.98 ± 0.11 / 1.16 ± 0.10, 1.13 ± 0.09 / 1.13 ± 0.11 and 1.17 ± 0.16 / 1.24 ± 0.08 nmol min^-1 mg protein^-1 (mean ± SD, male/female) in rats at 3, 8, 40 and older than 60 weeks of age, respectively. The results suggest that the DPD activity in the rat liver may not be affected by ageing or gender.