Phytohemagglutinin (PHA) activated human T-lymphocytes: concomitant appearance of insulin binding, degradation and insulin-mediated activation of pyruvate dehydrogenase (PDH).
Binding and degradation of A14125I-Insulin as well as the effect of insulin on pyruvate dehydrogenase (PDH) activation were studied in non-stimulated and phytohemagglutinin (PHA)-stimulated thymic-derived lymphocytes (T-lymphocytes) of man under varying conditions of time, temperature, and cell concentration. The nonstimulated viable T-lymphocytes exhibited neither binding, degradation, nor PDH activation in response to insulin. With PHA stimulation, a time and temperature-dependent binding was noted in T-lymphocytes which paralleled the appearance of cell-associated insulin degrading activity. Concomitant with the emergence of insulin binding and degrading activities in these cells, PDH activation was observed which was responsive to as little as 5.0 microU/ml of insulin. We conclude that in PHA-activated T-lymphocytes of man the process of insulin binding and degradation is closely related to insulin sensitive activation of PDH. These activated cells may serve as a useful model in which to study insulin binding and processing, as well as effects of insulin on postreceptor events.
D004789:Enzyme Activation; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000187:drug effects*; D010835:Phytohemagglutinins / Q000494:pharmacology*; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors
D007328:Insulin; D010835:Phytohemagglutinins; D011768:Pyruvate Dehydrogenase Complex