Effect of 15(R)-15-methyl PGE2 (arbaprostil) on duodenal bicarbonate secretion in rat.

The present study was designed to observe the effect of 15(R)-15-methyl PGE2 (arbaprostil) on duodenal bicarbonate secretion in male Wistar rats anesthetized with urethane. A proximal duodenal loop (1.5cm) was made and perfused with saline (pH4.5) in an air tight circle system. The pH and Pco2 of the perfusing fluid were measured continuously and the quantity of bicarbonate was calculated according to the Henderson-Hasselbalch equation. Vehicle or arbaprostil was injected intravenously as a bolus injection. The total output of bicarbonate in 30 min was as follows; control: 0.449 +/- 0.093 microEq (mean +/- SE); 1,10 and 100 mu/kg of arbaprostil: 0.752 +/- 0.218, 2.75 +/- 0.430 and 5.958 +/- 0.578 microEq respectively. Arbaprostil (10 and 100 micrograms/kg) increased the total output of bicarbonate significantly (p less than 0.001). The rate of secretion was also increased by arbaprostil.