AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 2 155-G160, Copyright © 1986 by American Physiological Society
Absorption of pantothenic acid in rat and chick intestine
D. K. Fenstermacher and R. C. Rose
Pantothenic acid absorption was evaluated in the intestine of rat and
chicken to reevaluate the concept that this nutrient crosses the mucosa by
simple diffusion. Unidirectional influx of [3H]pantothenic acid (0.9
microM) across the brush-border membrane of rat jejunum in vitro
demonstrates sodium dependence and saturation kinetics. Net transepithelial
transport (absorption) of pantothenic acid takes place in everted sacs of
jejunum against an electrochemical potential gradient. This accumulation
does not occur in tissue exposed to metabolic inhibitors. Also, pantothenic
acid accumulates in the transport cells of both rat and chicken intestine
against a 9- to 10-fold concentration gradient. Recently absorbed
pantothenic acid is freely diffusible from isolated chicken enterocytes. No
metabolic conversion of pantothenic acid was detected during absorption in
the intestine of either species under conditions in vitro or in vivo. The
present results indicate that pantothenic acid present at low
concentrations is absorbed in the intestine by a specific transport
mechanism; the process is best described as sodium-dependent, secondary
active transport.
