A cloned rat thyroid cell line (FRTL-5) was examined for both insulin binding and responsiveness. The characteristics of insulin binding to thyroid cells were similar to those observed in typical insulin target cells. The 125I-insulin binding was time and temperature dependent and Scatchard analysis suggested the presence of two major binding sites with high and low affinity constant (Kd = 1.4 x 10-10 mol/L and 1.5 x 10-9 mol/L, respectively). 125I-insulin was also internalized and degraded in a temperature-dependent manner. IGF1 was weakly effective in completing 125I-insulin binding to FRTL-5 cells (57% inhibition at 333 nmol/L), whereas noninsulin-related peptide hormones were ineffective. Exposure of FRTL-5 cells to insulin stimulated both methyl-aminoisobutyric acid (M-AIB) and 2-deoxy-D-glucose (2DG) transport. These effects were evident at 10-9 mol/L and maximal at 10-7 mol/L insulin. Maximal stimulation was three- to four-fold over basal value for both M-AIB and 2DG transport. These data suggest that insulin specifically binds to FRTL-5 cells and regulates different biological functions of this thyroid cell line.
INSULIN BINDING AND BIOLOGICAL-ACTIVITIES IN THE FRTL-5 RAT-THYROID CELL-LINE / Vincenzo, Trischitta; Giuseppe, Damante; Daniela, Foti; Filetti, Sebastiano. - In: METABOLISM, CLINICAL AND EXPERIMENTAL. - ISSN 0026-0495. - STAMPA. - 36:4(1987), pp. 379-383. [10.1016/0026-0495(87)90211-3]
INSULIN BINDING AND BIOLOGICAL-ACTIVITIES IN THE FRTL-5 RAT-THYROID CELL-LINE
Vincenzo Trischitta;FILETTI, SEBASTIANO
1987
Abstract
A cloned rat thyroid cell line (FRTL-5) was examined for both insulin binding and responsiveness. The characteristics of insulin binding to thyroid cells were similar to those observed in typical insulin target cells. The 125I-insulin binding was time and temperature dependent and Scatchard analysis suggested the presence of two major binding sites with high and low affinity constant (Kd = 1.4 x 10-10 mol/L and 1.5 x 10-9 mol/L, respectively). 125I-insulin was also internalized and degraded in a temperature-dependent manner. IGF1 was weakly effective in completing 125I-insulin binding to FRTL-5 cells (57% inhibition at 333 nmol/L), whereas noninsulin-related peptide hormones were ineffective. Exposure of FRTL-5 cells to insulin stimulated both methyl-aminoisobutyric acid (M-AIB) and 2-deoxy-D-glucose (2DG) transport. These effects were evident at 10-9 mol/L and maximal at 10-7 mol/L insulin. Maximal stimulation was three- to four-fold over basal value for both M-AIB and 2DG transport. These data suggest that insulin specifically binds to FRTL-5 cells and regulates different biological functions of this thyroid cell line.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.