In vitro transport of beta-lactoglobulin across the jejunum of lactose-fed rats.
Changes in protein absorption through the intestinal mucosa occur with aging and might reflect modifications in enterocyte membrane characteristics. We have observed that bovine beta-lactoglobulin (beta-LG) was efficiently transported across the small intestine of adult rats in vitro and that 12-16% of the absorbed protein was recovered intact or as large hydrophobic peptides. Ten percent lactose-feeding resulted in decreased tissue conductance and significantly reduced (-58%, P less than 0.05) beta-LG transport across rat small intestinal mucosa. The amounts of beta-LG absorbed, either as amino acids and peptides or as intact protein, were reduced to the same extent. Therefore, the effect of lactose feeding might be related to a decrease in protein endocytosis at the brush-border level, rather than to reduced protein transport across tight junctions.
Huneau
J F
JF
INRA, Laboratoire de Nutrition Humaine et Physiologie Intestinale, Paris, France.
Tomé
D
D
D000818:Animals; D001692:Biological Transport; D002851:Chromatography, High Pressure Liquid; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism; D007583:Jejunum / Q000378:metabolism; D007700:Kinetics; D007782:Lactoglobulins / Q000378:metabolism*; D007785:Lactose / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344
D007782:Lactoglobulins; D007785:Lactose