N. Utoguchi et al., CARRIER-MEDIATED TRANSPORT OF MONOCARBOXYLIC ACIDS IN PRIMARY CULTURED EPITHELIAL-CELLS FROM RABBIT ORAL-MUCOSA, Pharmaceutical research, 14(3), 1997, pp. 320-324
Purpose. Using primary cultured rabbit oral mucosal epithelial cells (
ROEpi), we investigated whether carrier-mediated drug absorption via t
he oral mucosal route occurs. Methods. Oral mucosal epithelial cells w
ere isolated from rabbit buccal mucosa and cultured on tissue culture
plates. When the cells reached confluence, drug uptake experiments wer
e performed. [C-14]Benzoic acid or [C-14]acetic acid was used as a mar
ker for monocarboxylic acid carrier-mediated transport. Results. The u
ptake of [C-14]benzoic acid by ROEpi occurred at a much lower rate at
4 degrees C than at 37 degrees C. The metabolic inhibitors, sodium azi
de and 2,4-dinitrophenol, significantly inhibited the uptake of [C-14]
benzoic acid by ROEpi. Various monocarboxylic acids inhibited the upt
ake of [C-14]benzoic acid or [C-14]acetic acid by ROEpi, whereas dicar
boxylic acids did not affect the uptake. Kinetic analysis using Linewe
aver-Burk plots revealed that acetic acid competitively inhibited the
uptake of [C-14]benzoic acid, and benzoic acid competitively inhibited
the uptake of [C-14]acetic acid by ROEpi. Conclusions. There exists a
carrier-mediated transport system for monocarboxylic acids in oral mu
cosal epithelial cells.