Urate metabolism and gastric ulcerations in rats as influenced by stress and allopurinol.

Stress and allopurinol (ALL) were investigated in rats with regard to their influence on serum uric acid and glucose concentration, gastric secretion, microcirculation (MBF) and stress ulcer index. There is a non-competitive type of interaction between severe stress and ALL-mediated xanthine oxydase inhibition (= per cent fall in serum uric acid) as compared with control conditions (= mild stress). Vmax is different (84.6 +/- 1.9 and 92.3+/-2.26; P less than 0.05), but not Km (0.39 +/- 0.09 and 0.68 +/- 0.08 mg/kg/h ALL). Serum uric acid is higher in rats with draining gastric fistula than those with closed fistula suggesting that already mild stress is associated with an increase in uricemia in this species. ALL does not significantly alter gastric acid and uric acid secretion but improves markedly gastric ulcer index during mild and severe stress. Since MBF is significantly elevated by ALL during the latter circumstances, a dissociation between MBF and acid secretion is one feature of ALL actions and might become a primary aim in treatment of this disorder.