THE LEVEL OF MAP KINASE-ACTIVITY IN THE STOMACH STUMP IN RATS AFTER SUBTOTAL GASTRECTOMY

MAPK (Mitogen - Activated Protein Kinase) is one of the elements of ki nase cascades (MAPK, MEK-MAP kinase, kinase, Raf-l, Pas) regulating ce llular proliferation and differentiation processes. It seems that the changes in its number and activity may be the factor having influence on carcinogenesis. In some human carcinomas a significant increase of its activity is observed, in others a decrease of its activity is desc ribed. Our research aimed at the evaluation of the dynamics of precanc erous and cancerous changes in the stomach stump in rats after the exp erimental, partial stomach resection. Apart from histological and ultr astructural examination we also determined the activity of the sub-uni t p42 MAP kinase. The material comprised segments of gastric mucosa of the stomach stump of 15 rats after subtotal gastrectomy. Part of the rats after the procedure were administered carcinogen orally (MNNG). O n the histological and ultrastructural examination we used routine met hods, the activity of MAP kinase was determined by western-blotting me thod with the use of IgG against MAPK p42, Santa Cruz #154). In 8 exam ined rats we observed the increase of MAP kinase activity. We establis hed probable correlation (without statistical analysis, regarding mise rly material) between the increase of MAPK activity and histological a nd ultrastructural changes. Among three cases diagnosed as adenoma tub ulare in two we observed the increase of MAPK activity. A clear increa se of this kinase was also present in the stomach stump of a rat, whic h was diagnosed as adenocarcinoma. On the basis of our research carrie d so far we think that the increase of the MAPK activity may be one of the causes of the neoplasm development. It seems important to obtain the confirmation of our results and to establish a possible usefulness of MAPK activity determination as a prognostic indicator in case of t he neoplasm of stomach stump.