Absorption of medium-chain lipids from the rat cecum

Abstract

1. Absorption of G14-labelecd octanoic acid (RAO) and glyceryl trioctanoate (RATO) from the isolated rat cecum were estimated by continuous monitoring of the expired C14O2 for 1 hr. 2. After RAO administration an average of 13.6% of the administered dose of radioactivity was recovered as C14O2. Thorough washing of the cecum prior to RAO instillation did not affect the rate of C14O2 recovery. 3. After intracecal administration of RATO, an average of 9.8% of the administered dose of radioactivity was recovered as C14O2. Prior washing of the cecum, however, resulted in a significant reduction in the mean C14O2 recovery, to 0.7%. 4. Samples of cecal contents aspirated at 20, 40, and 60 min, after trioctanoate instillation revealed the presence of detectable amounts of mono- and diglycerides when subjected to thin-layer chromatography. 5. From these results it would appear that significant amounts of octanoic acid and glyceryl trioctanoate can be absorbed from the rat cecum. While the absorption of this medium-chain fatty acid seems to proceed independently of luminal factors, the absorption of trioctanoate is preceded by luminal digestion by an active lipolytic system in the cecum.