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Receptor-linked degradation of 125I-insulin is mediated by internalization in isolated rat hepatocytes.

When hepatocytes were freshly isolated from rat liver and incubated for various periods of time at 37 degrees C, the media from the incubation, when completely separated from the cells, actively degraded 125I-insulin. THis soluble protease activity was strongly inhibited by bacitracin but was unaffe...

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Detalles Bibliográficos
Autores principales: Gorden, P., Freychet, P., Carpentier, J. L., Canivet, B., Orci, L.
Formato: Texto
Lenguaje:English
Publicado: Yale Journal of Biology and Medicine 1982
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596013/
https://www.ncbi.nlm.nih.gov/pubmed/6753361
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author Gorden, P.
Freychet, P.
Carpentier, J. L.
Canivet, B.
Orci, L.
author_facet Gorden, P.
Freychet, P.
Carpentier, J. L.
Canivet, B.
Orci, L.
author_sort Gorden, P.
collection PubMed
description When hepatocytes were freshly isolated from rat liver and incubated for various periods of time at 37 degrees C, the media from the incubation, when completely separated from the cells, actively degraded 125I-insulin. THis soluble protease activity was strongly inhibited by bacitracin but was unaffected by the lysosomatropic agent ammonium chloride (NH4Cl). When hepatocytes were incubated with 125I-insulin at 37 degrees C in the presence or absence of 8 mM NH4Cl the ligand initially bound to the plasma membrane and was subsequently internalized as a function of time. When hepatocytes were incubated at 37 degrees C for 30 minutes with 125I-insulin in the presence of bacitracin and NH4Cl or bacitracin alone and the cells were washed, diluted, and the cell-bound radioactivity allowed to dissociate, the percent intact 125I-insulin in the cell pellet and in the incubation media was greater in the presence of NH4Cl at each time point of incubation. Under these same conditions a higher proportion of the cell-associated radioactivity was internalized and a higher proportion was associated with lysosomes. The data suggest that receptor-mediated internalization is required for insulin degradation by the cell, and that this process, at least in part, involves lysosomal enzymes. Furthermore, the data demonstrate that internalization is not blocked by the presence of bacitracin or NH4Cl in the incubation media, but that degradation is inhibited.
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spelling pubmed-25960132008-12-05 Receptor-linked degradation of 125I-insulin is mediated by internalization in isolated rat hepatocytes. Gorden, P. Freychet, P. Carpentier, J. L. Canivet, B. Orci, L. Yale J Biol Med Research Article When hepatocytes were freshly isolated from rat liver and incubated for various periods of time at 37 degrees C, the media from the incubation, when completely separated from the cells, actively degraded 125I-insulin. THis soluble protease activity was strongly inhibited by bacitracin but was unaffected by the lysosomatropic agent ammonium chloride (NH4Cl). When hepatocytes were incubated with 125I-insulin at 37 degrees C in the presence or absence of 8 mM NH4Cl the ligand initially bound to the plasma membrane and was subsequently internalized as a function of time. When hepatocytes were incubated at 37 degrees C for 30 minutes with 125I-insulin in the presence of bacitracin and NH4Cl or bacitracin alone and the cells were washed, diluted, and the cell-bound radioactivity allowed to dissociate, the percent intact 125I-insulin in the cell pellet and in the incubation media was greater in the presence of NH4Cl at each time point of incubation. Under these same conditions a higher proportion of the cell-associated radioactivity was internalized and a higher proportion was associated with lysosomes. The data suggest that receptor-mediated internalization is required for insulin degradation by the cell, and that this process, at least in part, involves lysosomal enzymes. Furthermore, the data demonstrate that internalization is not blocked by the presence of bacitracin or NH4Cl in the incubation media, but that degradation is inhibited. Yale Journal of Biology and Medicine 1982 /pmc/articles/PMC2596013/ /pubmed/6753361 Text en
spellingShingle Research Article
Gorden, P.
Freychet, P.
Carpentier, J. L.
Canivet, B.
Orci, L.
Receptor-linked degradation of 125I-insulin is mediated by internalization in isolated rat hepatocytes.
title Receptor-linked degradation of 125I-insulin is mediated by internalization in isolated rat hepatocytes.
title_full Receptor-linked degradation of 125I-insulin is mediated by internalization in isolated rat hepatocytes.
title_fullStr Receptor-linked degradation of 125I-insulin is mediated by internalization in isolated rat hepatocytes.
title_full_unstemmed Receptor-linked degradation of 125I-insulin is mediated by internalization in isolated rat hepatocytes.
title_short Receptor-linked degradation of 125I-insulin is mediated by internalization in isolated rat hepatocytes.
title_sort receptor-linked degradation of 125i-insulin is mediated by internalization in isolated rat hepatocytes.
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596013/
https://www.ncbi.nlm.nih.gov/pubmed/6753361
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