Hepatic reduction of insulin-like growth factor (IGF)-I and IGF binding protein-3 that results from fasting is not attenuated in genetically obese rats

Kee Hyoung Lee, Jihui Zhang, Louis E. Underwood

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Fasting or caloric restriction causes substantial reductions in serum IGF-I in normal weight humans and animals, and reductions of liver IGF-I and IGFBP-3 mRNAs in animals. Obese humans, however, have attenuated and delayed decrements in IGF-I in serum when subjected to caloric restriction. Obese Zucker rats show a clear tendency to preserve body protein during fasting. To determine whether obesity opposes the effects of fasting on IGF-I and IGFBP-3, and thereby contributes to preservation of lean tissue, we have examined the effect of 72 h of fasting on IGF-I and IGFBP-3 in lean and obese Zucker rats. We observe that between lean and obese animals, fasting for 72 h produces similar decrements in body weight, serum IGF-I, liver IGF-I mRNA, serum IGFBP-3 and liver IGFBP-3 mRNA. Our finding that the reduction of IGF-I and IGFBP-3 in liver that results from 72 h of fasting is not attenuated in obese Zucker rats raises the possibility that conservation of lean tissue in these animals during fasting is not related to the hepatic production of IGF-I and IGFBP-3.

    Original languageEnglish
    Pages (from-to)664-670
    Number of pages7
    JournalJournal of Nutritional Biochemistry
    Volume13
    Issue number11
    DOIs
    Publication statusPublished - 2002 Nov 1

    Keywords

    • Fasting
    • IGF-I
    • IGFBP-3
    • Obesity

    ASJC Scopus subject areas

    • Endocrinology, Diabetes and Metabolism
    • Biochemistry
    • Molecular Biology
    • Nutrition and Dietetics
    • Clinical Biochemistry

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