Stimulation of Gastric Bicarbonate Secretion by an Analog of

The effects of YM-1 4673, a thyrotropin-releasing hormone ana-log, on gastric alkaline secretion were investigated in the anes-thetized rat pretreated with omeprazole (60 mg/kg, intraperito-neally) by measuring the luminal pH, transmucosal PD and HC03 output. The whole stomach was perfused at a flow rate of 0.7 mI/mm with saline (pH 4.5) in the absence of acid secretion, the pH of the perfusate and PD were continuously monitored and the HC03 output was measured as acid-neutralizing capacity by back-titration of the pertusate to pH 4.5. YM-14673, given intravenously at the doses (0.1-1 mg/kg) that stimulated acid secretion, increased the pH and HC03 output in a dose-de-pendent fashion, but did not significantly affect the PD. Prosta-glandin E2 (1 mg/kg) elevated the pH and HC03 output with concomitant decrease in the PD, whereas carbachol (4 zg/kg)