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Postnatal amino acid uptake by the rat small intestine. Changes in membrane transport systems for amino acids associated with maturation of jejunal morphology.
J Dev Physiol. 1979 Apr; 1(2):111-26.JD

Abstract

The uptake of a number of amino acids by the developing small intestine of the rat was investigated in vitro. L-valine, L-leucine, L-methionine, L-phenylalanine, L-arginine and L-lysine were all taken up by active transport and concentrated within the jejunal mucosa. GABA was not actively transported by the jejunum. The kinetics of carrier transport of amino acids was determined from birth to maturity. The Michaelis constant (Km) of the L-leucine, L-methionine, L-arginine and l-lysine transport systems was found to be low postnatally and increased with age, particularly after the time of weaning. The rate of l-leucine, L-methionine, L-phenylalanine and L-lysine transport (Vmax) was high postnatally but decreased after weaning. Neutral amino acids were transported at higher rates than basic amino acids. l-arginine was poorly transported by the jejunum. The specificity of transport systems for amino acids was investigated in inhibition studies. Amino acid transport systems appeared to be polyfunctional in the postnatal period but were more specific in post-weaned animals. The changes in kinetics and specificity of amino acid transport in the small intestine are discussed with reference to their possible functional significance and to the maturational changes in the jejunum, particularly with the appearance of a functionally distinct absorptive cell lining the intestinal villi during the third postnatal week (the time of weaning).

Authors

No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

121999

Citation

Murphy, S, and V G. Daniels. "Postnatal Amino Acid Uptake By the Rat Small Intestine. Changes in Membrane Transport Systems for Amino Acids Associated With Maturation of Jejunal Morphology." Journal of Developmental Physiology, vol. 1, no. 2, 1979, pp. 111-26.
Murphy S, Daniels VG. Postnatal amino acid uptake by the rat small intestine. Changes in membrane transport systems for amino acids associated with maturation of jejunal morphology. J Dev Physiol. 1979;1(2):111-26.
Murphy, S., & Daniels, V. G. (1979). Postnatal amino acid uptake by the rat small intestine. Changes in membrane transport systems for amino acids associated with maturation of jejunal morphology. Journal of Developmental Physiology, 1(2), 111-26.
Murphy S, Daniels VG. Postnatal Amino Acid Uptake By the Rat Small Intestine. Changes in Membrane Transport Systems for Amino Acids Associated With Maturation of Jejunal Morphology. J Dev Physiol. 1979;1(2):111-26. PubMed PMID: 121999.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Postnatal amino acid uptake by the rat small intestine. Changes in membrane transport systems for amino acids associated with maturation of jejunal morphology. AU - Murphy,S, AU - Daniels,V G, PY - 1979/4/1/pubmed PY - 1979/4/1/medline PY - 1979/4/1/entrez SP - 111 EP - 26 JF - Journal of developmental physiology JO - J Dev Physiol VL - 1 IS - 2 N2 - The uptake of a number of amino acids by the developing small intestine of the rat was investigated in vitro. L-valine, L-leucine, L-methionine, L-phenylalanine, L-arginine and L-lysine were all taken up by active transport and concentrated within the jejunal mucosa. GABA was not actively transported by the jejunum. The kinetics of carrier transport of amino acids was determined from birth to maturity. The Michaelis constant (Km) of the L-leucine, L-methionine, L-arginine and l-lysine transport systems was found to be low postnatally and increased with age, particularly after the time of weaning. The rate of l-leucine, L-methionine, L-phenylalanine and L-lysine transport (Vmax) was high postnatally but decreased after weaning. Neutral amino acids were transported at higher rates than basic amino acids. l-arginine was poorly transported by the jejunum. The specificity of transport systems for amino acids was investigated in inhibition studies. Amino acid transport systems appeared to be polyfunctional in the postnatal period but were more specific in post-weaned animals. The changes in kinetics and specificity of amino acid transport in the small intestine are discussed with reference to their possible functional significance and to the maturational changes in the jejunum, particularly with the appearance of a functionally distinct absorptive cell lining the intestinal villi during the third postnatal week (the time of weaning). SN - 0141-9846 UR - https://www.unboundmedicine.com/medline/citation/121999/Postnatal_amino_acid_uptake_by_the_rat_small_intestine__Changes_in_membrane_transport_systems_for_amino_acids_associated_with_maturation_of_jejunal_morphology_ DB - PRIME DP - Unbound Medicine ER -