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AMINO ACID TRANSPORT IN THE DEVELOPING CHICKEN KIDNEY
Author(s) -
Cooke Helen,
Young JA
Publication year - 1973
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1973.17
Subject(s) - alanine , reabsorption , amino acid , tyrosine , glycine , hatching , medicine , endocrinology , kidney , lysine , biology , endogeny , excretion , renal function , embryo , chemistry , biochemistry , zoology , microbiology and biotechnology
Summary The excretion and reabsorption of the amino acids alanine, glycine, tyrosine and lysine by the kidney were studied in chick embryos 1 day before hatching and in newly hatched chickens 5‐ or 10‐days‐old. Endogenous clearances of glycine, tyrosine and lysine were markedly lower in embryos than in hatched chickens. However, when endogenous clearances were expressed relative to glomerular filtration rate the percentages of the filtered loads of alanine, glycine and tyrosine excreted were greater in the embryo than in the hatched chickens; only for lysine was there an increase after hatching in the percentage of the filtered load excreted. Reabsorptive rates (expressed per g of kidney tissue) of lysine, glycine and alanine increased markedly after hatching but tyrosine reabsorption remained relatively constant. The results are consistent with the hypothesis that the affinities or capacities of the active transport systems increase with developmental age and that the various transport systems believed to exist seem not to develop at the same rate. Exogenous alanine clearances were studied in 10‐12‐day‐old chickens. As plasma concentrations of alanine increased absorption also increased and no tubular transport maximum could be demonstrated.