Insulin degradation by adipose tissue. Studies at several levels of cellular organization

Goldstein, Barry J.; Livingston, James N.

doi:10.1042/bj1860351

Cited by 25 publications

(9 citation statements)

References 39 publications

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“…INSULIN METABOLISM AND DEGRADATION 217 The intermediate sized peak obtained in some studies has been considered to be A-chain by some investigators (50), but others have concluded that it was not A-chain partly because the elution position appeared to be too large to be A-chain (134). We have found an intermediate sized product after incubation of labeled insulin with a liver cell membrane preparation that had no GIT activity (70) (Fig.…”

Section: Spring 1981mentioning

confidence: 81%

Insulin Metabolism and Degradation*

1981

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Section: Spring 1981mentioning

confidence: 81%

Insulin Metabolism and Degradation*

1981

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“…One enzyme, called insulin-degrading enzyme (IDE) (14), insulin protease (15,16), or insulinase, has been implicated in this degradation since it cleaves insulin in a limited number of sites (17), which are consistent with the peptide intermediates found in cells (18,19). Also this enzyme accounts for most of the insulin-degrading activity present in extracts of many different cell types (20)(21)(22)(23).…”

mentioning

confidence: 77%

Inhibition of insulin degradation by hepatoma cells after microinjection of monoclonal antibodies to a specific cytosolic protease.

Shii¹,

Roth²

1986

Proc. Natl. Acad. Sci. U.S.A.

109

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Four monoclonal antibodies were identified by their ability to bind to 12-I-labeled insulin covalently linked to a cytosolic insulin-degrading enzyme from human erythrocytes. All four antibodies were also found to remove more than 90% of the insulin-degrading activity from erythrocyte extracts. These antibodies were shown to be directed to different sites on the enzyme by mapping studies and by their various properties. Two antibodies recognized the insulin-degrading enzyme from rat liver; one inhibited the erythrocyte enzyme directly; and two recognized the enzyme after gel electrophoresis and transfer to nitrocellulose filters. By this latter procedure and immunoprecipitation from metabolically labeled cells, the enzyme from a variety of tissues was shown to be composed of a single polypeptide chain of apparent Mr 110,000. Finally, these monoclonal antibodies were microinjected into the cytoplasm of a human hepatoma cell line to assess the contribution of this enzyme to insulin degradation in the intact cell. In five separate experiments, preloading of cells with these monoclonal antibodies resulted in an inhibition of insulin degradation of 18-54% (average 39%) and increased the amount of 125I-labeled insulin associated with the cells. In contrast, microi'jection of control antibody or an extraneous monoclonal antibody had no effect on insulin degradation or on the amount of insulin associated with the cells. Moreover, the monoclonal antibodies to the insulin-degrading enzyme caused no significant inhibition of degradation of another molecule, low density lipoprotein. Thus, these results support a role for this enzyme in insulin degradation in the intact cell.

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“…Goldstein and coworkers found that freshly isolated, intact mouse fat pads degraded *10% of exogenously added insulin after only 90 min of incubation at 37°C. 14 Jochen and coworkers reported that the amount of insulin internalized by a suspension of freshly isolated human adipocytes peaked after 30 min of incubation at 37°C. 15 By this time, 40% of the total insulin associated with the cells was internalized.…”

Section: Discussionmentioning

confidence: 99%

Adipocyte Induction of Preadipocyte Differentiation in a Gradient Chamber

Lai

Sims²,

Jeon³

et al. 2012

Tissue Engineering Part C: Methods

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Adipose tissue expansion involves enlargement of mature adipocytes and the formation of new adipocytes through the differentiation of locally resident preadipocytes. Factors released by the enlarged adipocytes are potential cues that induce the differentiation of the preadipocytes. Currently, there are limited options to investigate these cues in isolation from confounding systemic influences. A gradient generating microfluidic channel-based cell culture system was designed to enable solution patterning, while supporting long-term culture and differentiation of preadipocytes. Solution patterning was confirmed by selectively staining a fraction of uniformly seeded preadipocytes. An adipogenic cocktail gradient was used to induce the differentiation of a fraction of uniformly seeded preadipocytes and establish a spatially defined coculture of adipocytes and preadipocytes. Varying the adipogenic cocktail gradient generated cocultures of preadipocytes and adipocytes with different compositions. Transient application of the cocktail gradient, followed by basal medium treatment showed a biphasic induction of differentiation. The two phases of differentiation correlated with a spatial gradient in adipocyte size. Our results provide in vitro data supporting the size-dependent release of preadipocyte differentiation factors by enlarged adipocytes. Prospectively, the coculture system developed in this study could facilitate controlled, yet physiologically meaningful studies on paracrine interactions between adipocytes and preadipocytes during adipose tissue development.

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Insulin degradation by adipose tissue. Studies at several levels of cellular organization

Cited by 25 publications

References 39 publications

Insulin Metabolism and Degradation*

Insulin Metabolism and Degradation*

Inhibition of insulin degradation by hepatoma cells after microinjection of monoclonal antibodies to a specific cytosolic protease.

Adipocyte Induction of Preadipocyte Differentiation in a Gradient Chamber

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