Interactions of soybean lectin, soyasaponins, and glycinin with rabbit jejunal mucosa in vitro.
Mucosal samples from rabbit jejunum were incubated (30 min, 25 degrees C) with (125I)glycinin in the presence of buffer, soybean lectin (50 micrograms/ml) soyasaponins (1 mg/ml), or both lectin and saponins. The mucosal uptake of (125I)glycinin was negligible with buffer, and increased progressively with additions of soybean lectin (P less than 0.05), soyasaponins (P less than 0.005), and both (P less than 0.0001). The stimulation of uptake by lectin and saponins together was greater than the sum of their individual effects (P less than 0.0005). The effect of soybean lectin on glycinin uptake was concentration dependent, reaching a maximum at approximately 50 micrograms/ml for the stimulation of uptake in the presence of saponins, and was inhibited by D-GaINAc. Although the mechanisms involved in mucosal uptake of glycinin cannot be described from these data, we have assumed the presence of two independent pathways for lectin-stimulated and saponin-induced uptakes. In addition, we have proposed that soybean lectin, by binding to terminal galactoside sites at the enterocyte apical membrane, enhances a crenator effect of saponins that leads to increasing leakage of glycinin into the cell.
D000818:Animals; D004347:Drug Interactions; D005916:Globulins / Q000378:metabolism*; D006358:Hot Temperature; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D007457:Iodine Radioisotopes; D007583:Jejunum / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism*; D037121:Plant Lectins; D014674:Plant Proteins, Dietary / Q000378:metabolism*; D011817:Rabbits; D012503:Saponins / Q000378:metabolism*; D030262:Soybean Proteins; D013025:Glycine max; D010835:Phytohemagglutinins
D005916:Globulins; D007457:Iodine Radioisotopes; D037102:Lectins; D037121:Plant Lectins; D014674:Plant Proteins, Dietary; D012503:Saponins; D030262:Soybean Proteins; C028824:soybean lectin; D010835:Phytohemagglutinins; C011474:glycinin