Postprandial increase in the duodenal pH and the effect of intravenous secretin injection on ionic compositions of duodenal fluid and plasma in sheep.
Testing five castrated male sheep with a pH-electrode inserted into the duodenal digesta through a T-shaped cannula, we found that the pH of the duodenal digesta was significantly increased from 3.11 +/- 0.11 to 3.47 +/- 0.09 after a meal. Secretin (2.5 CHR U/kg) was intravenously injected to mimic the duodenal pH increase. The administration significantly increased the duodenal digesta pH from 3.32 +/- 0.18 to 4.85 +/- 0.61, which was accompanied by an increase in sodium concentration, but by a decrease in potassium and chloride concentrations. It also significantly decreased the arterial blood pH from 7.543 +/- 0.002 to 7.515 +/- 0.008, which was accompanied by a reduced plasma HCO3- concentration. From these results, we conclude that in sheep, feeding increases the duodenal digesta pH, and the postprandial pH increase in the duodenal fluid would be due to the raised HCO3- secretion from the gastrointestinal tract.
Katoh
K
K
Department of Animal Physiology, Tohoku University, Faculty of Agriculture, Sandai, Japan.
Yamazaki
A
A
Sasaki
Y
Y
Tsuda
T
T
D000136:Acid-Base Equilibrium; D000818:Animals; D001769:Blood / Q000378:metabolism*; D001826:Body Fluids / Q000378:metabolism*; D004386:Duodenum / Q000378:metabolism*; D004435:Eating; D006863:Hydrogen-Ion Concentration; D007275:Injections, Intravenous; D007477:Ions; D008297:Male; D009994:Osmolar Concentration; D012633:Secretin / Q000494:pharmacology*
D007477:Ions; D012633:Secretin