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TRANSPORT OF LYSINE FROM CEREBROSPINAL FLUID OF THE CAT
Author(s) -
Cutler R. W. P.
Publication year - 1970
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1970.tb02255.x
Subject(s) - lysine , cerebrospinal fluid , arginine , glycine , amino acid , choroid plexus , chemistry , ornithine , biochemistry , cystine , kinetics , medicine , biology , endocrinology , enzyme , central nervous system , physics , quantum mechanics , cysteine
—The clearance from cerebrospinal fluid of l‐[ 14 C]lysine and l‐[ 3 H]arginine was measured during ventriculo‐cisternal perfusions of anaesthetized cats. Increasing in the perfusate the concentration of unlabelled l‐lysine produced a gradual reduction in clearance of the labelled amino acids without altering the uptake of l‐[ 14 C]lysine by the choroid plexus. Net transport of l‐lysine out of cerebrospinal fluid occurred by saturable and non‐saturable components. The saturable component satisfied Michaelis‐Menton kinetics, while the behaviour of the non‐saturable component was consistent with diffusion. A V max of 0·017 μmol/min and an affinity constant (k t ) of 0·83 mm were estimated. The clearance of l‐lysine was unaffected by the addition to the perfusate of high concentrations of selected neutral amino acids, but was stimulated by the presence of l‐cystine. Conversely, a high concentration of l‐lysine did not affect the clearance of glycine or cycloleucine. The dibasic amino acids appear to be removed from cerebrospinal fluid by a relatively specific, mediated transport system which may serve to regulate their concentrations in the cerebrospinal fluid.