Functioning of systems of the neutral amino acid transport in enterocyte brush-border membranes of rat small intestine under normal conditions and after ionising radiation.

Peculiarities of neutral amino acid (L-leucine and L-phenylalanine) transport in brush-border membranes of rat small intestine enterocytes under normal conditions and following a 1.0-Gy X-ray irradiation have been studied. The increase of the brush-border membrane permeability for ions and amino acids is considered to be the main reason of the post-irradiation disorders in the transmembrane transport of amino acids. The radiobiological approach made it possible to corroborate the existence of a Na+-dependent L-phenylalanine transport system different from the common system for neutral amino acids.

[Effect of ionizing radiation on the structure and functional properties of the basolateral membrane of small intestine enterocytes]. / Vliianie ioniziruiushchei radiatsii na strukturu i funktsional'nye svoistva bazolateral'noi membrany énterotsitov tonkogo kishechnika.

The structural state and transport properties of basolateral membrane of rat small intestine enterocytes after exposure to X-ray irradiation (0.5; 1.0 and 2.0 Gy) were studied. The substantional suppression of the active Ca(2+)-transport process concomitant to versatile changes of the membrane structure involving the surface sites and intramembrane protein-lipid complexes was revealed one day after irradiation. Taking into account the early obtained data on apical membrane functional disorders these results confirm that ionizing radiation in sublethal doses induces the structure-function modification of enterocyte plasma membrane affecting the function of the small intestine epithelial cells.