Hyperinsulinemia, but not other factors associated with insulin resistance, acutely enhances colorectal epithelial proliferation in vivo
| Autor: | Adria Giacca, W. Robert Bruce, Andrei I. Oprescu, Thien T. Tran, Gail McKeown-Eyssen, Loretta Lam, Dinaz Naigamwalla |
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| Rok vydání: | 2006 |
| Předmět: |
Male
medicine.medical_specialty Fat Emulsions Intravenous Colon medicine.medical_treatment Endocrinology Insulin resistance Intestinal mucosa In vivo Internal medicine Hyperinsulinism medicine Hyperinsulinemia Animals Insulin-Like Growth Factor I Intestinal Mucosa Cell Proliferation business.industry Insulin Growth factor Body Weight Rectum medicine.disease Rats Inbred F344 Rats Regression Analysis Insulin Resistance Energy source business Colorectal Neoplasms |
| Zdroj: | Endocrinology. 147(4) |
| ISSN: | 0013-7227 |
| Popis: | The similarity in risk factors for insulin resistance and colorectal cancer (CRC) led to the hypothesis that markers of insulin resistance, such as elevated circulating levels of insulin, glucose, fatty acids, and triglycerides, are energy sources and growth factors in the development of CRC. The objective was thus to examine the individual and combined effects of these circulating factors on colorectal epithelial proliferation in vivo. Rats were fasted overnight, randomized to six groups, infused iv with insulin, glucose, and/or Intralipid for 10 h, and assessed for 5-bromo-2-deoxyuridine labeling of replicating DNA in colorectal epithelial cells. Intravenous infusion of insulin, during a 10-h euglycemic clamp, increased colorectal epithelial proliferation in a dose-dependent manner. The addition of hyperglycemia to hyperinsulinemia did not further increase proliferation. Intralipid infusion alone did not affect proliferation; however, the combination of insulin, glucose, and Intralipid infusion resulted in greater hyperinsulinemia than the infusion of insulin alone and further increased proliferation. Insulin infusion during a 10-h euglycemic clamp decreased total IGF-I levels and did not affect insulin sensitivity. These results provide evidence for an acute role of insulin, at levels observed in insulin resistance, in the proliferation of colorectal epithelial cells in vivo. |
| Databáze: | OpenAIRE |
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