Effects of oxytetracycline on the rat exocrine pancreas

Objectives. Given the appearance of pancreatitis attributed to tetracycline , as described in the literature, we have investigated its effect on the en zymatic content of pancreas and duodenal fluid and on pancreatic ultrastruc ture. We have evaluated possible differences between sexes and the relation of our findings with those described in the initial phases of acute pancre atitis, in the context of the acinar hypothesis. Methods. With 128 Wister rats (63 male and 65 female), 3 groups were establ ished: control (group I) experimental animals treated with oxytetracycline intramuscularly, 15 and 30 mg/kg/d (groups II and III, respectively). Befor e sacrifice? half of the rats in each group were stimulated with cholecysto kinin. Blood, pancreatic tissue (for enzyme dosage and morphological study) , and duodenal fluid were extracted following anesthesia. Results, The stimulated males of group III presented lower amylase levels i n pancreatic tissue and duodenal fluid (P < 0.003). Just the opposite occur red in female rats. A similar tendency was observed with other enzymes (lip ase and trypsin). Zymogen granule counts, appearance of immature granules, and dilation of ergastoplasm were more frequent in the stimulated animals. Conclusions. Oxytetracycline seems to induce morphofunctional changes in ra t pancreas, which differ according to sex. In the female, enzyme accumulati on that could predispose intracellular activation seems; to exist, as well as the ultrastructural findings described in initial phases of acute experi mental pancreatitis. This agrees with the greater frequency of pancreatitis in women undergoing tetracycline treatment described in the literature. In contrast, for males the findings were more compatible with decrease of pro tein synthesis. This would make them less susceptible to crinophagy phenome na and, thus, to acute pancreatitis in the context of the acinar or lysosom e hypothesis.