Amino acid transport by aggregates of cultured chicken heart cells. Effect of insulin.
Single heart cells dissociated from 14-day-old chicken embryos were reagregated into spheroidal clusters on a gyratory shaker and centrifuged to form cohesive discs of approximately 400 aggregates. These cultured cells accumulated 2-amino[1-14C]isobutyric acid against a gradient. When incubated for 3 hours in a protein-free, buffered, balanced salt solution, concentrative transport decreased to a stable basal level. Incubation in the presence of sodium bovine insulin prevented this fall in transport activity and resulted in increased 2-aminoisobutyric acid uptake to concentrations 40 time sthat in the medium during a subsequent 3-hour transport assay. Intracellular accumulation of 2-aminoisobutyric acid was linear during the initial 15 min of transport in the presence and absence of added insulin. Basal transport of 2-aminoisobutyric acid was temperature-dependent, requied extracellular sodium greater than 125 meg/liter, and demonstrated saturation with an apparent Vmax of 3.4 mmol/liter/10 min and an apparent Km of 2.6 mM. Basal transport activity was not reduced by cycloheximide or puromycin even after 3 hours of exposure...
D000621:Aminoisobutyric Acids / Q000378:metabolism*; D000818:Animals; D001693:Biological Transport, Active; D002449:Cell Aggregation / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D003486:Cyanides / Q000494:pharmacology; D004058:Diffusion; D004140:Dinitrophenols / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology*; D007461:Iodoacetates / Q000494:pharmacology; D007700:Kinetics; D008433:Mathematics; D009206:Myocardium / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology
D000621:Aminoisobutyric Acids; D003486:Cyanides; D004140:Dinitrophenols; D007328:Insulin; D007461:Iodoacetates; D012964:Sodium; D005947:Glucose; D011188:Potassium