We have recently developed an in vitro system of pancreatic acinar AR42J cells, a highly differentiated rat cell line. In addition, we have developed a primary monolayer culture system of mouse pancreatic acinar cells which allows studies of normal cell function over a period of several weeks. The objective of this proposal is to determine which hormones have direct regulatory effects on pancreatic acinar cell growth and differentiation, and to elucidate the mechanisms involved, by utilizing these two culture systems. We will test: hormones that regulate intracellular Ca2+, (e.g. cholecystokinin); hormones that act via cyclic AMP (e.g. secretin); hormones that act via tyrosine kinase activity (e.g. insulin); and steroid hormones. To identify hormones which regulate growth, we will measure DNA synthesis, protein and DNA content, and the nuclear labeling index. We will test the hypothesis that CCK increases the growth of pancreatic acinar cells by the same mechanisms that mediate CCK induced enzyme secretion, by evaluating the effects of other Ca2+-mediated secretagogues, and of pharmacological agents which directly increase intracellular Ca2+, or activate protein kinase C. Variant strains of AR42J cells with unique growth properties will also be developed to help elucidate the mechanism involved in CCK induced growth. To identify hormones which regulate acinar cell differentiation we will test effects on pancreatic secretory enzyme synthesis using biosynthetic labeling, immunoprecipitation, and two-dimensional gel electrophoresis. To determine the mechanisms by which these hormones affect enzyme synthesis, we will utilize in vitro translation and nucleic acid hybridization with cDNA probes to quantitate changes in the acinar cell mRNA. Nuclear run-off assays will be conducted to determine whether changes in mRNA levels represent changes in transcription, or mRNA stability. Effects on cellular morphology will be evaluated by morphometric analysis and immunocytochemistry. The longterm regulation of CCK receptors by CCK and other factors will be determined by analysis of hormone binding, internalization and synthesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK035912-04
Application #
3234189
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1987-11-01
Project End
1989-07-31
Budget Start
1988-08-01
Budget End
1989-07-31
Support Year
4
Fiscal Year
1988
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
Nicke, B; Tseng, M J; Fenrich, M et al. (1999) Adenovirus-mediated gene transfer of RasN17 inhibits specific CCK actions on pancreatic acinar cells. Am J Physiol 276:G499-506
Detjen, K; Fenrich, M C; Logsdon, C D (1997) Transfected cholecystokinin receptors mediate growth inhibitory effects on human pancreatic cancer cell lines. Gastroenterology 112:952-9
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; Dabrowski, A; Williams, J A et al. (1996) Stress-activated protein kinase activation is the earliest direct correlate to the induction of secretagogue-induced pancreatitis in rats. Biochem Biophys Res Commun 227:1-7
Dabrowski, A; Grady, T; Logsdon, C D et al. (1996) Jun kinases are rapidly activated by cholecystokinin in rat pancreas both in vitro and in vivo. J Biol Chem 271:5686-90
Simeone, D M; Yule, D I; Logsdon, C D et al. (1995) Ca2+ signaling through secretagogue and growth factor receptors on pancreatic AR42J cells. Regul Pept 55:197-206
Detjen, K; Yang, J; Logsdon, C D (1995) Muscarinic acetylcholine receptor down-regulation limits the extent of inhibition of cell cycle progression in Chinese hamster ovary cells. Proc Natl Acad Sci U S A 92:10929-33
Detjen, K; Tseng, M J; Logsdon, C D (1995) High- and low-affinity CCKA receptor states mediate specific growth inhibitory effects on CHO cells. Biochem Biophys Res Commun 213:44-51
Hoshi, H; Logsdon, C D (1993) Both low- and high-affinity CCK receptor states mediate trophic effects on rat pancreatic acinar cells. Am J Physiol 265:G1177-81

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