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AMINO ACID AND GLUCOSE UPTAKE BY THE ISOLATED PERFUSED GUINEA‐PIG MAMMARY GLAND
Author(s) -
Davis S. R.,
Mepham T. B.
Publication year - 1974
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1974.sp002251
Subject(s) - amino acid , alanine , medicine , proline , guinea pig , perfusion , biology , endocrinology , glutamic acid , valine , in vivo , casein , biochemistry , mammary gland , leucine , tryptophan , aspartic acid , glucose uptake , insulin , microbiology and biotechnology , cancer , breast cancer
A technique has been developed for perfusion of the isolated guinea‐pig mammary gland. Perfusate flow rates per unit weight of tissue were similar to in vivo mammary blood flow in lactating rats and 2–3 times mammary blood flow in the lactating cow and goat. Amino acid uptake was measured by the arterio‐venous difference technique. The uptake of ‘essential’ amino acids correlated with their relative content in guinea‐pig milk protein, but uptake of ‘non‐essential’ amino acids was insufficient to account for the predicted rate of protein synthesis. Uptake of most amino acids was dependent on the rate of supply of exogenous substrates. Glucose uptake was variable but mean uptake during perfusion correlated with the rate of substrate infusion and gland weight. After addition of [U‐ 14 C]glucose to the perfusate in one experiment, alanine, serine, glutamic acid, aspartic acid and proline residues in milk casein became significantly labelled. The maintenance of high perfusate flow rates was found to depend on the attention paid to filtration of the perfusate, but the rate of amino acid uptake was probably dependent on the availability of tryptophan.