lucifer-yellow and lauroylcarnitine

We examined the effect of acylcarnitines on the in situ bioavailability of lucifer yellow (LY) from the loops of small and large intestines of rats. The area under the blood concentration of LY versus time curve (AUC) from the jejunum was significantly increased by the treatments of the loop with 100 µM lauroylcarnitine (LC) or 100 µM palmitoylcarnitine (PC) (fourfold and 17-fold, respectively). No marked change in the expression of claudin-4 protein was observed by the treatments. On the contrary, the expression of P-glycoprotein (P-gp) was decreased by the treatment, more greatly by PC than by LC, suggesting that increases in the bioavailability of LY by LC and PC are associated with the decreased expression of P-gp in jejunum. The increase in the bioavailability was also observed for colon by the treatment of LC, but not that of PC. LC decreased the expression of claudin-4 protein, whereas PC decreased the expression of P-gp in colon. Therefore, LC and PC appear to have different impact on the intestinal transporters depending on the site (i.e., jejunum and colon).

Topics: Administration, Oral; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Availability; Carnitine; Claudin-4; Colon; Fluorescent Dyes; Injections, Intravenous; Intestinal Absorption; Isoquinolines; Jejunum; L-Lactate Dehydrogenase; Laurates; Male; Palmitoylcarnitine; Rats; Rats, Wistar

This study examined the effects of the absorption enhancers, acylcarnitines, on efflux transporting systems, including P-glycoprotein (P-gp) and other efflux transporters, and elucidated the importance of acyl chain length and the concentration of acylcarnitine on the activity of efflux transport. The effects of two acyl (lauroyl and palmitoyl) carnitines on the influx and efflux of lucifer yellow and fluorescein isothiocyanate dextran 4,000, which have characteristic vectorial transport, were examined in Caco-2 cell monolayers. Lauroylcarnitine and palmitoylcarnitine increased influx and decreased efflux of these substrates, in a manner dependent on their concentration and acyl chain lengths by increasing influx and inhibiting efflux of the substrates. The results indicated that both the acyl moiety and long acyl chains play important roles in the modification of influx and efflux transport. Because no marked changes in the levels of P-gp protein or the leakage of LDH were observed at 1 h after the application of acylcarnitines, it was concluded that these acylcarnitines had an effect on modulation of the function of P-gp or other efflux transporters without cytotoxicity.

Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Caco-2 Cells; Carnitine; Dextrans; Fluorescein-5-isothiocyanate; Fluorescent Dyes; Humans; Isoquinolines; L-Lactate Dehydrogenase; Laurates; Palmitoylcarnitine