Development of nutrient transport systems in chick jejunum.
Glutamate, beta-alanine, choline, and myoinositol transport was characterized in jejunal slices and brush-border membrane vesicles from 2- and 21-day chicks. Carrier-mediated, i.e., competitor-inhibitable, transport in slices (wet weight basis) and vesicles (protein basis) declined with age for the two amino acids but increased with age for myo-inositol; transport of choline did not change. These findings, along with previous data for the hexose system, cannot be explained solely by nonspecific changes in brush-border membrane architecture or permeability or by changes in the electrochemical sodium gradient that drives cotransport. They indicate that each specific brush-border membrane transport mechanism follows separate developmental time tables.
D000818:Animals; D001692:Biological Transport; D002463:Cell Membrane Permeability; D002645:Chickens / Q000254:growth & development*; D002794:Choline / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D007294:Inositol / Q000378:metabolism; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D007583:Jejunum / Q000254:growth & development*; D007700:Kinetics; D008871:Microvilli / Q000378:metabolism; D009994:Osmolar Concentration; D015091:beta-Alanine / Q000378:metabolism
D005971:Glutamates; D015091:beta-Alanine; D018698:Glutamic Acid; D007294:Inositol; D002794:Choline