The objectives of this project are to investigate the molecular mechanisms through which the conditionally essential nutrient glutamine and the peptide growth factor IGF I (insulin-like growth factor 1) stimulate anabolic responses in cells and tissues. Previous work has demonstrated a nutritional requirement for the amino acid glutamine that develops in humans and experimental animals with catabolic disease states arising from such diverse etiologies as traumatic injury, infection, major operation, cancer chemotherapy, the short bowel syndrome, and malnutrition. Plasma concentrations of IGF I often are decreased in the same catabolic disease states that are characterized by a deficiency of glutamine, and recent studies have demonstrated anabolic tissue responses when IGF I is administered under these conditions. In preliminary studies, we have observed an additive or synergistic anabolic interaction when glutamine and IGF I are given in combination to experimental animals. The specific objectives of this project are to investigate the anabolic effects of glutamine and IGF I, their molecular mechanisms of action, and the underlying basis and significance of interactions between glutamine and IGF I. The experimental approach will involve studies on elements of the anabolic responses to glutamine and IGF I in laboratory rats following fasting, feeding with a low protein diet, or partial intestinal resection to create a model of the short bowel syndrome. Signalling events and regulatory molecules involved in the responses to IGF I and glutamine will be investigated with methods that use specific antibodies to assess tyrosine kinase activity, phosphatidylinositol 3-kinase activity, and the levels of signalling intermediates in animal tissues. Northern blotting and related methods will be used to study the expression of transcription activators and other regulatory molecules. Selected mRNA sequences that are modulated in response to glutamine and/or IGF I will be investigated using the recently developed method for differential-display of cDNA fragments following PCR amplification. These studies will increase our understanding of the fundamental mechanisms through which glutamine and IGF I produce anabolic effects in mammalian tissues. This information is essential for developing a rational approach to the use of glutamine- supplemented nutrition and IGF I, alone or in combination, in a broad spectrum of clinical disorders characterized by tissue catabolism and malnutrition.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK048503-03
Application #
2148848
Study Section
Nutrition Study Section (NTN)
Project Start
1994-09-01
Project End
1998-08-31
Budget Start
1996-09-01
Budget End
1998-08-31
Support Year
3
Fiscal Year
1996
Total Cost
Indirect Cost
Name
Joslin Diabetes Center
Department
Type
DUNS #
071723084
City
Boston
State
MA
Country
United States
Zip Code
02215
Wang, P H; Almahfouz, A; Giorgino, F et al. (1999) In vivo insulin signaling in the myocardium of streptozotocin-diabetic rats: opposite effects of diabetes on insulin stimulation of glycogen synthase and c-Fos. Endocrinology 140:1141-50
Qu, Z; Ling, P R; Chow, J C et al. (1998) Effects of dietary protein and tumor necrosis factor on components of the insulin-like growth factor-I pathway in the colon and small intestine in protein-depleted rats. Metabolism 47:345-50
Ziegler, T R; Mantell, M P; Chow, J C et al. (1998) Intestinal adaptation after extensive small bowel resection: differential changes in growth and insulin-like growth factor system messenger ribonucleic acids in jejunum and ileum. Endocrinology 139:3119-26
Qu, Z; Chow, J C; Ling, P R et al. (1997) Tissue-specific effects of chronic dietary protein restriction and gastrostomy on the insulin-like growth factor-I pathway in the liver and colon of adult rats. Metabolism 46:691-7
Giorgino, F; Pedrini, M T; Matera, L et al. (1997) Specific increase in p85alpha expression in response to dexamethasone is associated with inhibition of insulin-like growth factor-I stimulated phosphatidylinositol 3-kinase activity in cultured muscle cells. J Biol Chem 272:7455-63
Porch, J V; Jain, K; Reilly, A et al. (1997) Aging, physical activity, insulin-like growth factor I, and body composition in Guatemalan women. Am J Clin Nutr 66:874-9
Chow, J C; Ling, P R; Qu, Z et al. (1996) Growth hormone stimulates tyrosine phosphorylation of JAK2 and STAT5, but not insulin receptor substrate-1 or SHC proteins in liver and skeletal muscle of normal rats in vivo. Endocrinology 137:2880-6
Ziegler, T R; Mantell, M P; Chow, J C et al. (1996) Gut adaptation and the insulin-like growth factor system: regulation by glutamine and IGF-I administration. Am J Physiol 271:G866-75
Giorgino, F; Smith, R J (1995) Dexamethasone enhances insulin-like growth factor-I effects on skeletal muscle cell proliferation. Role of specific intracellular signaling pathways. J Clin Invest 96:1473-83
Mantell, M P; Ziegler, T R; Adamson, W T et al. (1995) Resection-induced colonic adaptation is augmented by IGF-I and associated with upregulation of colonic IGF-I mRNA. Am J Physiol 269:G974-80

Showing the most recent 10 out of 11 publications