Characterization of butyrate-dependent electroneutral Na-Cl absorption in the rat distal colon.
Recent studies have established that mucosal butyrate stimulates electroneutral sodium-chloride (Na-Cl) absorption in the distal colon of the rat and a model in which Na-hydrogen (H) and Cl-butyrate exchanges are coupled has been proposed as the mechanism of butyrate-dependent electroneutral Na-Cl absorption. These studies were designed to examine butyrate-dependent electroneutral Na-Cl absorption in experimental conditions in which HCO3-dependent electroneutral Na-Cl absorption is inhibited: in Na-depleted (aldosterone-treated) animals and in the presence of increased mucosal cyclic adenosine monophosphate (AMP). Butyrate-dependent electroneutral Na-Cl absorption was markedly reduced in Na-depleted rats. In contrast, the inhibition of both net Na and net Cl absorption by 5 mM serosal theophylline was significantly less in butyrate-containing, HCO3-free Ringer solution than in butyrate-free- HCO3-containing Ringer solution. These studies indicate that cyclic AMP does not inhibit butyrate-dependent electroneutral Na-Cl absorption and we propose that the mechanism of cyclic AMP inhibition of HCO3-dependent electroneutral Na-Cl absorption may be a result of its inhibition of Cl-HCO3, not Na-H exchange.
Binder
H J
HJ
Department of Internal Medicine, Yale University, New Haven, CT 06510.
Mehta
P
P
D000450:Aldosterone / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D002087:Butyrates / Q000494:pharmacology*; D003106:Colon / Q000378:metabolism* / Q000502:physiology; D007408:Intestinal Absorption / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012965:Sodium Chloride / Q000493:pharmacokinetics*; D013806:Theophylline / Q000494:pharmacology
D001639:Bicarbonates; D002087:Butyrates; D012965:Sodium Chloride; D000450:Aldosterone; D013806:Theophylline