Effects of the new anti-ulcer agent 12-sulfodehydroabietic acid monosodium salt on duodenal alkaline secretion in rats.

Alkaline secretion was measured by pH-stat titration (pH 7.4) during circulation of 0.15 mol/l NaCl through the duodenal lumen in urethane-anesthetized rats. 12-Sulfodehydroabietic acid monosodium salt (TA-2711), at concentrations of 5 and 10 mg/ml, instilled into the circulating fluid at pH 7.4 caused a slight increase in alkaline secretion. When the duodenal lumen was acidified to pH 2.0 for 5 min by instillation of HCl into the circulating fluid, a remarkable increase in alkaline secretion occurred. Addition of TA-2711 (5 and 10 mg/ml) to the circulating fluid considerably enhanced the acid-induced alkaline secretion, with a concurrent increase in prostaglandin E2 release into the circulating fluid. These effects of TA-2711 were inhibited by the pretreatment with indometacin (10 mg/kg s.c.). The results indicate that TA-2711 has an enhancing effect on acid-induced alkaline secretion and endogenous prostaglandins may be involved in the alkaline secretion enhanced by TA-2711.