Effects of dexamethasone and N(G)-nitro-L-arginine methyl ester (L-NAME), the nitric oxide (NO) synthase inhibitor, on caerulein-induced acute pancreatitis were examined in rats. Acute pancreatitis was induced by caerulein (20 mug/kg, s.c.) given repeatedly 2 or 4 times every hour, and serum amylase levels, pancreas weight and myeloperoxidase (MPO) activity were measured 6 h after the first injection of caerulein. Dexamethasone (3 mg/kg) and L-NAME (30 mg/kg) were administered p.o. 30 min before the first injection of caerulein. Caerulein caused moderate or severe pancreatitis, depending on the times of injections, resulting in different degrees of increase in serum amylase levels and pancreas weight, and the marked elevation of MPO activity was observed only after injections of caerulein given 4 times per hour. Both dexamethasone and L-NAME suppressed the severity of pancreatits, yet the effect of L-NAME as compared with dexamethasone was more potent against mild pancreatitis but less potent against severe pancreatitis. These results suggest that caerulein-induced acute pancreatitis shows different responsiveness to L-NAME and dexamethasone, depending on the severity; the former is more effective against pancreatitis with less inflammation, while the latter is more effective against pancreatitis with severe inflammation. It is assumed that endogenous NO may be involved in oedema formation as the early event in the development of acute pancreatitis.

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PEPS proved to be a feasible new technique for diagnosing chronic pancreatitis, and it was able to detect abnormal findings more clearly than other imaging methods.

Electronic pancreatoscopy with the PEPS is feasible in most patients and technically safe, and improves diagnostic yield over conventional pancreatoscopy.

Stress is reportedly known to affect the severity of acute pancreatitis, yet the effect has not been without controversy. We investigated the influence of restraint stress on cerulein-induced pancreatitis, especially in relation to endogenous glucocorticoids. In the present study, restraint stress significantly reduced the increase in serum amylase levels but not pancreas weight induced by cerulein, the effect being totally antagonized by pretreatment with mifepristone, a glucocorticoid receptor antagonist. The changes induced by cerulein were prevented by dexamethasone in a dose-dependent manner. Histologically, restraint stress suppressed the intralobular edema, similar to a low dose of dexamethasone, while the latter at a high dose prevented not only the intralobular but also the interlobular edema. These results suggest that restraint stress exerts a beneficial influence on the cerulein-induced pancreatitis, mainly mediated by endogenous glucocorticoids, and it is assumed that short-term steroid therapy has a potential of clinical application for treatment of pancreatitis.