A302 AGA ABSTRACTS GASTROENTEROLOGY Vol. 1I8, No.4

Results: GLP-l was not released with duodenal glucose at1kcallmin. Duodenal glucose at2.Skcal/min significantly increased plasma GLP-1 which was further augmented byIVEx-9. With Ex-9.11 antral phases IIIwere recorded compared to2with saline.

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GLP-l(7-36)AMIDE (GLP-l) IS A PHYSIOLOGICAL REGULA­TOR OF HUMAN ANTRO·PYLORO·DUODENAL MOTILITY.Joerg J. Schirra, Uwe Wank, Rudolf Arnold, Burkhard Goeke, MartinKatschinski, Philipps Univ, Marburg, Germany; Inselspital, Univ of Bern,Berne, Switzerland.

This study addressed the role of the incretin hormone GLP-l in regulatingantro-pyloro-duodenal motor functions using the specific GLP-l receptorantagonist exendin(9-39)amide (Ex-9). Methods: In 9 healthy volunteers,antro-pyloro-duodenal motility and TMPD were recorded usin¥. a sleevetechnique against background infusions of Ex-9 (300 pmolekg .min-1lorsaline. Following a 30 min interdigestive period, glucose was duodenallyperfused at 1 and 2.5 kcallmin for 60 min each. These glucose loads arebelow and above the threshold of GLP-l release, respectively (J Clin Invest1996;97:92). Conclusions: Even basal circulating GLP-l levels tonicallyinhibit antroduodenal motility and suppress antral MMC's, both in theinterdigestive state and with the low duodenal glucose load. Postprandialrelease of GLP-l by the high glucose load (3.2 ± 0.9 pM over basal)distinctly diminishes antroduodenal contractile activity but stimulates pha­sic and tonic pyloric motility. However, glucose mediated inhibition ofantroduodenal and stimulation of pyloric motility only partially rely uponGLP-l but also occur independently, most likely via direct interaction withintestinal glucose receptors. Furthermore, we suggest a negative auto­feedback regulation of GLP-l release in human.

Parameter IVinfusion Pyloric tone IPPWsJl0 min Antral Duodenal(mmHg) wavesJl0 min wavesJl0 min

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PHAMACOKINETICS OF PROGRASTRIN DERIVED PEPTIDES.Adrienne C. Paterson, Arthur Shulkes, Graham S. Baldwin, Univ of Mel­bourne, Melbourne, Australia.

There is substantial evidence that progastrin-derived peptides stimulate thegrowth of normal colonic epithelium, are elevated in the circulation ofpatients with colorectal carcinomas (CRCs), and are synthesized by mostCRCs (Baldwin and Shulkes, 1998). We have recently produced humanrecombinant progastrin6_80 and have examined the in vivo and in vitropharmacokinetics in sheep. Methods In Vitro Fresh ovine plasma (N=3)was spiked with recombinant human progastrin6_80. The plasma was im­mediately incubated at 37°C or 4°C for up to 24 hours. Samples were takenat various time points and snap frozen. In Vivo Progastrin6_80, (500 pmol),tyr70-progastrin70_80 or gastrin.sgly were injected on separate occasionsinto conscious sheep (N=4) via a cannula in the jugular vein. Bloodsamples were taken at various time points between 0 and 120 min and theplasma frozen. Peptide concentrations were measured by radioimmunoas­say (RIA) using antisera directed against the C termini of human progastrinor gastrin17-gly. Results In Vitro Progastrin was very stable in buffer orovine plasma at 37°C and 4°C, with no measurable degradation after 24hours. In Vivo The disappearance half-life of progastrin6_80 (12.1 ± 1.0min) was substantially longer than for gastrm.sgly (8.6 ± 0.5 min) ortyr70-progastrin70_80 (1.1 ± 0.1 min). The +10 minute sample from theprogastrin6_80 experiment was chromatographed on a sizing column butonly a single immunoreactive peak eluting in the position of progastrin 6-80was detected. Summary Recombinant human progastrin6_80 is stable inplasma, and has an in vivo half-life of 12.1 minutes in sheep. The half-livesof gastrin.sgly and tyr70-progastrin70_80 were significantly shorter. Therewas no detectable cleavage of progastring.g, to smaller forms reactive to Cterminal antisera. Conclusion The long half life suggests that progastrin ifsecreted should be detected in the circulation. Baldwin, G.S. and ShulkesA. (1998) Gastrin, gastrin receptors and colorectal carcinoma Gut 42:581­584

Interdigesl. saline 1.7 ± 0.6 1.6±0.S 4.8±1.S 31.0± 4.8Ex-9 27± O.S 2.0 ± O.S 12.1 ± 1.9' 54.7 ± 9.2'

1kcalfmin saline S.4 ± 0.9# 4.4±1.0# 2.3 ± 0.5# 24.4 ± 2.2#Ex-9 S.3 ± 0.6# 2.3 ± O.S' 7.8±1.4' 42.9 ± S.9'

2.5 kcallmin saline 8.9 ± 13t 103± 1.6t 1.S ± OSt 142± 2.3tEx-9 S.8 + 1.0' 4.3±1.4' 2.8 ± 0.6't 32.7 ±4.6'#

': P<O.OS vs saline. #:P<O.OS vs inlerdigestive state; t:P<O.OS vsduodenal glucose at1kcal/min.IPPW: isolated pyloric pressure wave

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EVIDENCE FOR A ROLE OF CCK AND GASTRIN IN THEPATHOGENESIS OF ACID HYPERSECRETION IN H. PYLORIINFECTION.Frank Schmitz, Frank Zumbansen, Babette Reimann, Jan M. Otte, MichaelN. Goeke, Erhard G. Siegel, Jochen Peters, Wolfgang E. Schmidt, UlrichR. Foelsch, 1 Dept of Medicine Univ of Kiel, Kiel, Germany; 1 Dept ofMedicine, Kiel, Germany; Dept of Gastroenterology, Univ of Hannover,Hannover, Germany; Institute for Pathology, Kiel, Germany; Dept ofMedicine I, Ruhr Univ, Bochum, Germany.

BACKGROUND: CCK activates both CCK-A and CCK-B/gastrin recep­tors (CCK-BR) while gastrin selectively recognizes the CCK-BR subtype.Gastrin stimulates acid secretion, whereas CCK has been shown to be apotent negative regulator of acid secretion and gastrin release in humans(Schmidt et al. 1994). One candidate mechanism by which CCK suppressesacid secretion is through release of somatostatin (SST) by activation ofCCK-AR on D cells. Accumulating evidence suggests that H. pylorigastritis (HPG) of the antrum suppresses SST release from D cells whichresults in hypergastrinemia and increased acid secretion. At present, it isuncertain whether hypersecretion in HPG is related to a defect of theCCK-mediated release of SST. AIM: To determine the sites of action ofCCK and gastrin in individual cells of the normal gastric mucosa and inHPG. METHODS: Mucosal biopsies from 40 patients undergoing upper GIendoscopy were utilized for (1) isolation of total RNA (2) RT-PCR insituin paraffin-embedded tissue sections (3) immunohistochemistry (IH)and confocal laser scanning microscopy (CLSM) to identify CCK receptor­expressing cells in situ. RESULTS: CCK-AR and CCK-BR transcriptswere identified in both antral and oxyntic mucosa by PCR in vitro.CCK-AR expression mapped primarily to non-parietal cells as depicted byRT-PCR in situand lB. Counterstaining by IH revealed that mRNACCK_ARwas amplified within the cytosol of chief cells, mucous neck cells, andSST-producing D cells. A small fraction of parietal cells (15%) alsoexpressed mRNAccK_AR' CCK-BR transcripts were identified primarily inacid-secreting parietal cells within oxyntic mucosa. 51 % of parietal cellswithin the isthmic and neck region of the gastric gland expressed CCK-BRtranscripts in situ. In addition, ECL cells also expressed mRNACCK_BR' ThemRNA expression of both CCK receptor subtypes was confirmed byepitope-specific antisera directed against the CCK-A or CCK-BR protein.DISCUSSION: The CCK receptor expression analysis in situreveals that Dcells bearing CCK-AR mRNA and protein may function as prime target forCCK. The inhibition of gastrin-induced acid secretion by CCK in humansis likely to result from CCK-AR-mediated release of SST from D cells.Hence, hypersecretion in HPG is likely to occur by a defect of theCCK-SST link. (Supported by DFG)

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THERAPY OF MICROCIRCULATORY DYSFUNCTION INACUTE PANCREATITIS WITH I.V. APPLICATION OF BOVINEHEMOGLOBIN IN THE RAT.Tim G. Strate, Helge Kleinhans, Oliver Mann, Claus G. Schneider, ThomasStandi, Jakob R. Izbicki, Christian Bloechle, Univ of Hamburg, Hamburg,Germany.

Background: Stasis of the pancreatic microcirculation (PM) initiates andaggravates acute pancreatitis (AP). Hydroxy-Ethyl-Starch (HAES) hasbeen shown to improve pancreatic microcirculation. Similarly, bovinehemoglobin (BH) improves rheology due to its colloid effect, but alsosupplies additional oxygen to the tissue. The aim of this study was toevaluate the therapeutic effect of BH on PM in severe AP. Material andMethods: In Wistar rats, AP was induced by administration of gluco­deoxycholic-acid (10 mmolJl, 1 mlIkg) i.d, and cerulein (5 j.l.gIkglh) i.v..Leukocytes were marked with Acridine Orange and PM was continuouslymonitored by fluorescence microscopy. 15min. after the initiation of AP,animals received either 0.8 ml BH, HAES or 0.9% NaCI i.v, at random.After 6 hrs, animals were sacrificed and histopathological damage of thepancreas was assessed using a validated histology score (0-16; no-max.damage). Results: In comparison with the NaCI group, PM improvedsignificantly in the BH group (capillary density 70 vs. 33%, p=0.002,leukocyte adherence (LA) 27 vs. 56%, p=O.OO4). Histology score revealedless tissue damage in the BH group (6.25 vs. 9.25 (3-8.5 vs. 8.25-10.25,p=0.027)). Amylase level was reduced in the BH group by 81.2 UIL, whileit increased by 3420 UIL (p=O.Oll). TAP level was lower compared withthe NaCI group (11.7nmolJl vs. 23.3 nmolJl; p=0.019) This therapeuticeffect of BH became only partially apparent in the HAES treated animals.PM only improved regarding LA (36.8 vs. 56%, p=0.017). Histology scoreimproved only regarding fatty necrosis and hemorrhage (1.75 vs. 2.75(1.5-2.75 vs. 2.25-3.5, p=0.036)), but not regarding the total score (8 vs.9.25 (6.5-10.25 vs. 8.25-10.25, ns.). Conclusion: In severe AP, singletherapeutic i.v. administration of BH improves PM and reduces histologictissue damage. This effect could only partially be demonstrated adminis­tering HAES. The additional beneficial effect is probably due to plasmabound oxygen, that allows for better tissue oxygenation in the severelydamaged pancreatic tissue, thus maintaining not only flow, but oxygen­ation.