Reduced insulin-like growth factor (IGF, or somatomedin) activity in diabetes may contribute to decreased growth, poor wound healing, and impaired anabolism. While blood IGF levels may be low, circulating levels of IGF inhibitors are high and may further reduce net IGF activity in diabetes. Because inhibitors are similar in size (molecular weight 20- 40kDa) to recently characterized IGF binding proteins (BPs), we asked whether changed in BPs may contribute to high circulating inhibitory activity in diabetes. Analysis by Sephacryl S-200 chromatography and affinity labeling techniques confirmed a marked increase sue to changes in BPs of appropriate molecular weight (20 to 50kDA) in streptozotocin- diabetic animals. We now have applied ligand blot, immunoblot, immunoprecipitation, and northern blot techniques to identify a specific 32kDa BP that is responsible for these changes in diabetes, and is distinct from the previously characterized low molecular weight IGF BP present in fetal rat serum (BP-3A). Since 32kDa BPs are normalized by insulin therapy, regulation of these BPS may represent one mechanism by which insulin, and other hormones, may modulate growth processes and anabolism in diabetes and other disease states. To further investigate this possibility, specific tools will now be developed to examine mechanisms of 32kDa BP regulation in vivo and in vitro. Our recent observation that the hormone-responsive, well differentiated H4IIE rat hepatoma cell line secretes this 32kDa protein in roller bottle culture will greatly facilitate BP purification and provide a model for initial in vitro studies of regulation. Purified BP will be used to prepare specific antiserum and to obtain amino acid sequence data for subsequent development of cDNA probes to investigate specific mechanisms of BP regulation in intact animals, and isolated cells. Since the liver appears to be an important site of IGF BP and inhibitor production, late hepatic 32kDA BP production, attention will be focused on identifying hormonal and/or metabolic factors that modulate hepatic 32kDa BP production, providing the basis for subsequent investigations regarding specific mechanisms of BP regulation. Since IGFs are growth regulators for many cell types, studies now proposed should provide better understanding of the regulation of cell growth and other anabolic processes in diabetes, and other metabolic diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
1R29DK041430-01A1
Application #
3463827
Study Section
Endocrinology Study Section (END)
Project Start
1990-01-01
Project End
1994-12-31
Budget Start
1990-01-01
Budget End
1990-12-31
Support Year
1
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Illinois at Chicago
Department
Type
Schools of Medicine
DUNS #
121911077
City
Chicago
State
IL
Country
United States
Zip Code
60612
Deng, Xiong; Zhang, Wenwei; O-Sullivan, InSug et al. (2012) FoxO1 inhibits sterol regulatory element-binding protein-1c (SREBP-1c) gene expression via transcription factors Sp1 and SREBP-1c. J Biol Chem 287:20132-43
Cypess, Aaron M; Zhang, Hongbin; Schulz, Tim J et al. (2011) Insulin/IGF-I regulation of necdin and brown adipocyte differentiation via CREB- and FoxO1-associated pathways. Endocrinology 152:3680-9
Ganjam, Goutham Kumar; Dimova, Elitsa Y; Unterman, Terry G et al. (2009) FoxO1 and HNF-4 are involved in regulation of hepatic glucokinase gene expression by resveratrol. J Biol Chem 284:30783-97
Carroll, Robert E; Goodlad, Robert A; Poole, Aleksandra J et al. (2009) Reduced susceptibility to azoxymethane-induced aberrant crypt foci formation and colon cancer in growth hormone deficient rats. Growth Horm IGF Res 19:447-56
McLoughlin, Thomas J; Smith, Sierra M; DeLong, Alissa D et al. (2009) FoxO1 induces apoptosis in skeletal myotubes in a DNA-binding-dependent manner. Am J Physiol Cell Physiol 297:C548-55
Shambaugh 3rd, G E; Natarajan, N; Davenport, M L et al. (1995) Nutritional insult and recovery in the neonatal rat cerebellum: insulin-like growth factors (IGFs) and their binding proteins (IGFBPs). Neurochem Res 20:475-90
Zhao, X; Unterman, T G; Donovan, S M (1995) Human growth hormone but not human insulin-like growth factor-I enhances recovery from neonatal malnutrition in rats. J Nutr 125:1316-27
Ney, D M; Yang, H; Smith, S M et al. (1995) High-calorie total parenteral nutrition reduces hepatic insulin-like growth factor-I mRNA and alters serum levels of insulin-like growth factor-binding protein-1, -3, -5, and -6 in the rat. Metabolism 44:152-60
Goswami, R; Lacson, R; Yang, E et al. (1994) Functional analysis of glucocorticoid and insulin response sequences in the rat insulin-like growth factor-binding protein-1 promoter. Endocrinology 134:736-43
Lacson, R; Oehler, D; Yang, E et al. (1994) Dideoxy sequencing and structural analysis of the rat insulin-like growth factor binding protein-1 gene. Biochim Biophys Acta 1218:95-8

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