Gastrointestinal hormones are major regulators of the digestion and metabolism of food. Cholecystokinin, probably the most important of these hormones, regulates the exocrine and endocrine pancreas, gallbladder contraction, GI motility, and in addition, is a major neuropeptide. This proposal will continue work characterizing the receptors for CCK and other GI hormones.
Specific aims or projects include: 1) purification of the CCK receptor and generation and characterization of antibodies directed against the receptor; 2) characterization of the biosynthesis, processing, and turnover of the CCK receptor. The role of receptor glycosylation in maturation and function will be probed. The regulation of receptor biosynthesis and degradation by CCK and other hormones will be evaluated; 3) the role of distinct receptor affinity states in initiating biological responses will be evaluated using CCK analogy active on only one affinity state; 4) the cellular uptake and processing of CCK will be determined by electron microscope autoradiography and HPLC. Cellular uptake and recycling of the CCK receptor will also be evaluated; 5) other GI hormone receptors particularly for the pancreatic polypeptide peptide, PYY, NPY family will be characterized by ligand binding and cross-linking. The localization of receptors for these and other hormones in intact tissues such as the pancreas and stomach will be evaluated by autoradiography; 6) the mRNA coding for GI hormone receptors will be characterized by expression in Xenopus oocytes. Techniques developed for the CCK receptor mRNA will be extended to other Ca2+ mobilizing receptors. Other receptors will be characterized in oocytes by their electrophysiological effects on endogenous or exogenously inserted ion channels. These projects in total will extend our understanding of the molecular structure and function of GI hormone receptors and the action of GI hormones as physiological and pathophysiological regulators.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK041225-02
Application #
3241857
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1989-04-15
Project End
1994-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
2
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Owyang, Chung; Logsdon, Craig D (2004) New insights into neurohormonal regulation of pancreatic secretion. Gastroenterology 127:957-69
Zhang, Lizhi; Duan, Chao Jun; Binkley, Charles et al. (2004) A transforming growth factor beta-induced Smad3/Smad4 complex directly activates protein kinase A. Mol Cell Biol 24:2169-80
Ji, B; Bi, Y; Simeone, D et al. (2001) Human pancreatic acinar cells lack functional responses to cholecystokinin and gastrin. Gastroenterology 121:1380-90
Logsdon, C D (1999) The influence of the cellular context on receptor function: a necessary consideration for physiologic interpretations of receptor expression studies. Life Sci 64:369-74
Nicke, B; Detjen, K; Logsdon, C D (1999) Muscarinic cholinergic receptors activate both inhibitory and stimulatory growth mechanisms in NIH3T3 cells. J Biol Chem 274:21701-6
Dabrowski, A; Detjen, K M; Logsdon, C D et al. (1997) Stimulation of both CCK-A and CCK-B receptors activates MAP kinases in AR42J and receptor-transfected CHO cells. Digestion 58:361-7
Detjen, K; Yule, D; Tseng, M J et al. (1997) CCK-B receptors produce similar signals but have opposite growth effects in CHO and Swiss 3T3 cells. Am J Physiol 273:C1449-57
Grady, T; Liang, P; Ernst, S A et al. (1997) Chemokine gene expression in rat pancreatic acinar cells is an early event associated with acute pancreatitis. Gastroenterology 113:1966-75
Bragado, M J; Groblewski, G E; Williams, J A (1997) p70s6k is activated by CCK in rat pancreatic acini. Am J Physiol 273:C101-9
Blevins, G T; van de Westerlo, E M; Logsdon, C D et al. (1996) Nucleotides regulate the binding affinity of the recombinant type A cholecystokinin receptor in CHO K1 cells. Regul Pept 61:87-93

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