title: Entry of insulin into human cultured lymphocytes: electron microscope autoradiographic analysis.
abstract: Electron microscope autoradiographs were prepared of IM-9 human cultured lymphocytes incubated with iodine-125-labeled insulin. With the use of [125I]insulin and Ilford L-4 emulsion, the technique had a resolution half-distance of approximately 0.085 micrometer. Autoradiographs revealed a time-dependent entry of insulin into the cell interior that was maximal after 30 minutes of incubation. At this time point nearly 40 percent of the [125I]insulin was in the interior of the cell at a distance 1 micrometer or greater from the plasma membrane. Grain distribution and volume density analyses revealed that the intracellular insulin was concentrated in the endoplasmic reticulum and nuclear membrane.
mesh_terms: D001345:Autoradiography; D001692:Biological Transport; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*
chemical_list: D007328:Insulin