Basal and PGE2-stimulated duodenal bicarbonate secretion in the rat in vivo.
We studied basal and prostaglandin E2 (PGE2)-stimulated duodenal HCO3- transport in the rat in vivo both in the presence and absence of a concentration gradient for HCO3- from blood to lumen. Basal HCO3- transport was not reduced when the luminal solution was changed from one containing 0 mM HCO3- to one containing 22 mM HCO3- either at pH 9.0 or 7.5. Thus basal duodenal HCO3- transport in rats is independent of a blood-to-lumen HCO3- concentration gradient, which indicates an energy-dependent process with little passive flux of HCO3-. Luminal or intravenous administration of PGE2 significantly (P less than 0.01) increased HCO3- secretion into a HCO3(-)-free luminal solution but had no effect on HCO3- secretion into luminal solutions containing 22 mM HCO3-, either at pH 9.0 or 7.5. Therefore prostaglandins may act by increasing passive flux of HCO3- rather than by stimulating energy-dependent duodenal HCO3- transport.
Heylings
J R
JR
Department of Internal Medicine, Veterans Administration Medical Center, Dallas, Texas.
Feldman
M
M
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D015232:Dinoprostone / Q000494:pharmacology*; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D007408:Intestinal Absorption / Q000187:drug effects; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D001639:Bicarbonates; D015232:Dinoprostone