title: Kinetics of D-histidine diffusion across rat intestine in vitro.
abstract: A five-compartment linear model for diffusion in vitro across rat jejunum has been proposed for the study of the kinetic constants of D-histidine transport. Once preliminary experiments using 2,4-dinitrophenol and L-methionine have proved that D-histidine gives rise to passive transport only, the validity of the model was tested and its parameters estimated through a best-fitting procedure by using experimental data concerning D-histidine transport. D-Histidine diffusion was studied in everted and unreverted loops mounted in an oxygenated bath system. Both mucosa to serosa and seroa to mucosa movements of D-histidine (3-30 mM) were evaluated by measuring chemically the amount of D-histidine transported into intestinal lumen every 5 min for 60 min. Results obtained proved that D-histidine transport in each direction (mucosa to seroa or seroa to mucosa) was dependent-concentration process. Nevertheless different values of gain and time constants were estimated for the transport in the two directions.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004058:Diffusion; D004140:Dinitrophenols / Q000494:pharmacology; D006639:Histidine / Q000378:metabolism*; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000187:drug effects; D007413:Intestinal Mucosa / Q000378:metabolism; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008433:Mathematics; D008715:Methionine / Q000494:pharmacology; D008954:Models, Biological; D051381:Rats; D013237:Stereoisomerism
chemical_list: D004140:Dinitrophenols; D006639:Histidine; D001285:Atropine; D008715:Methionine