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>Hormonal regulation of amino acid transport and gluconeogenesis in primary cultures of adult rat liver parenchymal cells
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Hormonal regulation of amino acid transport and gluconeogenesis in primary cultures of adult rat liver parenchymal cells
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机译：Hormonal regulation of amino acid transport and gluconeogenesis in primary cultures of adult rat liver parenchymal cells
AbstractAmino 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. These cells carried out gluconeogenesis from three carbon precursors (alanine, pyruvate, and lactate) in response to glucagon addition. Amino acid transport was assayed by measuring the uptake of the nonmetabolizable amino acid, α‐aminoisobutyric acid (AIB). Addition of insulin or glucagon to cultured rat liver parenchymal cells resulted in an increased influx of AIB which was reflected in a higher initial rate of AIB transport. The glucocorticoid, dexamethasone, when added alone to cultures did not affect AIB transport. However, prior or simultaneous addition of dexamethasone to glucagon‐treated cells caused a strong potentiation of the glucagon induction of AIB transport. Kinetic analysis of the effects of insulin and glucagon demonstrated that insulin increased the Vmaxfor transport without changing the Kmwhile glucagon primarily decreased the Kmfor AIB transport. The effect of dexamethasone was to increase the Vmaxof the low Km
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