Absorption of short-chain fatty acids from the in-situ-perfused caecum and colon of the guinea pig

Abstract

Background: Short-chain fatty acids (SCFA) originate from microbial fermentation of carbohydrates in the hindgut. Mechanisms involved in SCFA absorption are not fully understood.

Methods: The caecum and proximal and distal colon of the guinea pig were perfused in situ.

Results: SCFA absorption per gram mucosal dry weight was highest in the proximal colon and lowest in the caecum. Owing to the large surface, quantitatively SCFA absorption was highest from the caecum. In the distal colon clearance of SCFA increased with chain length (Ac < Pr < Bu); in the caecum and proximal colon only a comparatively small or no such influence was observed. Inhibition of the proton antiport systems in the apical membrane and inhibition of the carbonic anhydrase activity diminished SCFA absorption. The diffusive and carrier components of absorption were calculated for propionate at increasing propionate concentrations.

Conclusions: Marked segmental differences in SCFA absorption are apparent in the large intestine of the guinea pig.