CHANGES IN ANNEXIN-I AND ANNEXIN-II LEVELS DURING THE POSTNATAL-DEVELOPMENT OF RAT PANCREATIC-ISLETS

The expression patterns and the dynamic changes in content of both ann exin I and annexin II in the rat pancreatic islets during postnatal de velopment were investigated by both western blot analysis and immunohi stochemistry. Immunohistochemical methods clearly demonstrated the pre sence of annexins I and II exclusively in pancreatic islets, while exo crine tissues were not stained by anti-annexin antibodies. Pancreatic islets were diffusely stained with no specific differences in distribu tion between different cell types. The expression of annexin I in panc reatic islets gradually increased with postnatal development. A develo pmental study of annexins I and II by western blot analysis essentiall y supported the results obtained by immunohistochemistry. In addition, the increasing expression of two protein tyrosine kinases, epidermal growth factor-receptor/kinase and pp60(src), which phosphorylate annex in I and annexin II, respectively, and of protein kinase C, which phos phorylates both proteins, was also shown during postnatal development in rat pancreatic islets. Thus, a relationship between the expression of annexins I and II and the maturation of islet cell function is sugg ested.