April 1 9 9 5 Pancreatic Disorders A 3 6 9

• GLUCOCORTICOID INDUCED PANCREATIC PROLIFERATION BY STIMULATION OF ORNITHINE DECARBOXYLASE EXPRESSION IN DEVELOPING RATS. P. C. Lee and Mark Struve Division of Gastroenterology, Department of Pediatrics, Medical College of Wisconsin, Milwankee, WI. Increased ornithine decarboxylase (ODC) expression is associated

with tissue proliferation and differentiation. We examined the role of ODC in glucocorticoid induced precocious proliferation and differentiation of the developing rat pancreas. Rat pups at various selected ages were treated with and without dexamethasone (DX) (0. lmg/Kg body weigh0 and their pancreata collected for the determination of ODC mRNA levels. Wet tissue weight, protein and DNA content were evaluated as index of proliferation. Lipase and amylase contents were measured as index of differentiation. In suckling rats (10 days old) significant increases in protein and amylase contents (2-3X) were found 24 hours after DX administration. Lesser increases in wet tissue weight and DNA content occurred. Corresponding increases in pancreatic ODC mRNAs (3-4X) were seen in the treated pups compared to control age-matched littermates. Increase in ODC mRNA was detectable 12 hours after DX, a time when there were minimal increases in other parameters of proliferation and differentiation. The increase in ODC mRNA in response to DX was age dependent as similar DX treatment in rats aged 25 day and older did not result in significant changes of ODC mRNA or in proliferation of the pancreas. The action of DX on ODC expression was receptor mediated as the increase in ODC mRNA levels was abolished by concomitant administration of U38486 (a type II specific glucocorticoid receptor antagonist) but not by spironolactone (a type I specific glucocorticoid receptor antagonis 0. DX induced pancreatic growth was likewise abolished by U38486 but not by spironolactone. The results indicated that glucocorticoid induced pancreatic proliferation in the neonatal rats acts via stimulation of ODC expression and that glucocorticoid probably acts at the pretranslational level.

PACAP STIMULATES PANCREATIC SECRETION VIA THE RELEASE OF SECRETIN AND CHOLECYSTOKININ (CCK) IN RAT. ST Lee KY Lee, TM Chang, "D Coy, WY Chey. University of Rochester Medical Center, Rochester, NY and "Tulane University Medical Center, New Odeans, LA.

Pituitary adenylate cyclase activating peptide (PACAP) stimulates protein and/or amylase secretion from isolated rat pancreatic acini. To study the effect of PACAP on pancreatic secretion in vivo and the mechanism of its action, the following study was carried, out in Urethane-anesthetized rats (weighing 250-300 gm) prepared with pancreatic and bile ducts cannulation and pyloric ligation. Jugular vein was catheterized to infuse saline or PACAP. After a 30 min basal period, PACAP-27 at doses of 2.5, 5, and 10 nmol/kg (n=6) given intravenously while pancreatic juice was collected for 30 rain per each dose of PACAP. In 3 other groups of rats, effect of PACAP, 10 nmol/kg was studied under the influence of either Ioxiglumide (L, 10 mg/kg, n=6), antisecretin serum (Anti-S, 0.1 ml, n=5) or L+Anti-S (n=5). Volume, bicarbonate and protein of pancreatic juice was measured. For RIA of secretin and CCK in plasma, venous blood was obtained from each rat 5 min after iv PACAP. Results: 1) PACAP significantly increased pancreatic secretion: flow volume, bicarbonate and protein in a dose-dependent manner; 2) the increase in pancreatic secretion paralleled that of plasma secretin and CCK levels (Table 1); 3) combination of L and Anti-S completely abolished the PAOAP-stimulated pancreatic secretion, whereas L or Anti-S alone partially blocked the pancreatic secretion. Table 1: Plasma concentrations (pM, mean + SE, n=6)

Basal PACAP (10 nmol/kq) Secretin 3.7t-0.6 "9.3-L-0.5 CCK 10.6±2.3 "22.8-'1:4.5

Table 2: Pancreatic secretion (%1") after PACAP (10 nmoVkg) PACAP +L +Anti-S +L+Anti-S

Volume 132±26 "33.-I:14 *36±7 0 Bicarbonate 175±44 "70+__3 "38±31 0 Protein 128±29 °27_+.26 *62+25 0

": p <0.05 - 0.01 over Basal or PACAP. In conclusion, PACAP-27 stimulates pancreatic secretion of water bicarbonate and protein in dose-dependent manner in rats. This increase is mediated by endogenous releases of both secretin and CCK.

PANCREATIC POLYPEPTIDE (PP) INHIBITS AN INSULIN ACTION ON PANCREATIC EXOCRINE SECRETION VIA INTRAPANCREATIC CHOLINERGIC NERVES. YL Lee, HS Park, HJ Park. Department of Physiology, College of Medicine, Hallym University, Kangwon-Do, Korea.

We have previously reported, in the isolated rat pancreas, that PP inhibits pancreatic exocdne secretion by reducing a potentiating action of insulin on cholecystokinin (CCK)-stimulated pancreatic exocrine secretion and that the insulin action is under an intrapancreatic cholinergic influence. It has been also reported that PP suppresses the intrapancreatic cholinergic activity. Thus, this study was aimed to see if PP reduces the insulin action via the intrapancreatic cholinergic nerves in the isolated rat pancreas. The isolated pancreas was peffused with modified Krebs-Henseleit solution containing 2.5 mM glucose, 0.1% BSA and 3% dextran via the celiac and superior mesenteric arteries at a speed of 1.2 ml/min. The volume flow and amylase output were determined from pancreatic juice collected in 15 min samples. Intra-arterial infusion of porcine insulin (100 nM) resulted in potentiation of the pancreatic volume flow and amylase output that were stimulated by CCK-8 (14 pM). As shown in the following table, rat PP (10 pM) completely abolished the potentiating actions of insulin on the CCK- stimulated pancreatic exocrine secretion. Vesamicol (10 p.M), a potent inhibitor of vesicular acetylcholine storage, reduced the combined actions of insulin and CCK-8. Carbamylcholine (50 pM) reversed the combined actions of insulin and CCK-8 inhibited by vesamicol. Also rat PP failed to attenuate the pancreatic exocrine secretion that was reversed from the vesamicol- induced inhibition by carbamylcholine.

Insulin + Cholecystokinin C +PP +V +V+Ch +V+Ch+PP

Volume 9.0 5.5" 4.9" 8.4 8,0 (111/15 rain) ±0.9 ±0,6 E).4 0.9 -ZO.8 Amylase 72.4 22.8 "81.9 "238.9 246.2 (U/15 rain) +49.3 +3.9 ±19.6 ±52.9 ±44.8

C: control, V: vesamicol, Ch: carbamylcholine. Mean + SE of six experiments; *:p<0.05 vs C. The results indicate that PP inhibits the potentiating action of insulin on CCK-stimulated pancreatic exocrine secretion by suppressing the intrapancreatic cholinergic activity in the isolated rat pancreas.

A UNIQUE PATTERN OF ILEOCAECAL GUT WALL MORPHOLOGY RELATED TO PANCREATIC ENZYME REPLACEMENT THERAPY: AN ULTRASONOGRAPHY STUDY IN 200 CYSTIC FIBROSIS-PATIENTS B. Lembcke, M. Pohl, B. Kreckhardt, H.G. Posselt. Centers of Internal Medicine & Pediatrics, University Hospital, Frankfurt, Germany

As pancreatic steatorrhea in patients with cystic fibrosis (CF) is partially resistent to conventional pancreatin therapy, high-strength pan- creatin preparations have been developed. Recently, strictures of the asc. colon and caecum leading to intestinal obstruction have been disco- vered as a new entity in CF-patients, which were attributed to high- strength pancreatic enzymes (Lancet 1994; 343:85-86). Aim: To investi- gate gut wall morphology (wall thickness and layers) with respect to pan- creatic enzyme therapy in the cohort of 260 CF-patients from our institu- tions. Method: 214 CF-patients (1-38 years) and 12 controls were studied by high-resolution real time ultrasonography (US) of the small and large bowel from April - August 1994. 123 Patients had high-strength pancraatin preparations (HSP; >20,000 units lipase/dose), 69 patients normal-strength pancreatin (NSP; 10,000 units/dose), and 8 patients did not require pancreatin. In 14 cases US was unsatisfactory. US was performed by a single investigator (B.L) who did not know the patients before and was unaware of their therapy. The wall thickness of the terminal ileum, caecum, ascending and descending colon was measured both in longitudinal and transverse sections, and the pattern of the gut wall layers was registered. Results: Patients with CF receiving pancreatin had a distinct ileocaecal US pattern with prominent submucosal layer. Gut wall thickening was significant in the ileum with NSP and HSP, in the caecum additionally also without pancreatin, and in the asc. colon with HSP only. The effect was correlated to high strength-preparations but not to the daily dose of enzyme replacement ther~ Table: means _+ SD

Ileum Caecum Asc. Colon Desc. Colon I control (n=12) 1.23_+0.20 1.29-z0.14 1.214-0.21 1.154-0.17 No enzymes (n= 8 ) 1.314-0.39 1.82_+0.69 1.27~0.13 1.41_+0.19 NSP (n=69) 1.604-0.55 1.944-0.75 1.544-0.70 1.32±0.41 HSP (n=123) 1.76_40.55 2.38_+0.97 1.72±0.77 1.50/-0.63

Conclusion: US detects characteristic ileocaecal wall lesions (a regular pattern of submucosal prominence [fibrosis]) in the majority of CF- patients on pancreatic enzymes. These lesions may lead to significantly increased ileocaecel wall thickness, which is correlated but not restricted to high-strength enzyme preparations.