title: Induction of amino acid transport in primary cultures of adult rat liver parenchymal cells by insulin.
abstract: Amino acid transport was studied in primary cultures of parenchymal cells isolated from adult rat liver by a collagenase perfusion technique and maintained as a monolayer in a serum-free culture medium. Amino acid transport was assayed by measuring the uptake of the nonmetabolizable amino acid, alpha-aminoisobutyric acid. Rat liver parenchymal cells transported alpha-aminoisobutyric acid by an energy-dependent Na+-requiring system which displayed Michaelis-Menten kinetics. Addition of insulin to cultured rat liver parenchymal cells resulted in an increased influx of alpha-aminoisobutyric acid which was reflected in a higher initial rate of alpha-aminoisobutyric acid transport as well as an increased accumulation of alpha-aminoisobutyric acid at later time points. Cycloheximide effectively blocked the increase while results with actinomycin D were equivocal. Insulin at concentrations as low as 50 pM was effective in stimulating alpha-aminoisobutyric acid transport while the maximal response was observed at 80 nM.
mesh_terms: D000621:Aminoisobutyric Acids / Q000378:metabolism*; D001693:Biological Transport, Active / Q000187:drug effects; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D007424:Intracellular Fluid / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008757:Methylglucosides / Q000378:metabolism; D012964:Sodium / Q000494:pharmacology
chemical_list: D000621:Aminoisobutyric Acids; D007328:Insulin; D008757:Methylglucosides; D003609:Dactinomycin; D003907:Dexamethasone; D003513:Cycloheximide; D012964:Sodium; D005947:Glucose