[Ultrastructural analysis of reactive changes in the exo- and endocrine epithelium of embryonal pancreas in organ cultures].

The purpose of the work was to study reactive changes of endocrine and exocrine epithelii of the rat embryonic pancreas in organic culturation. The culturation was carried out at 34 degrees C and in the nutritional mixture of the following composition: medium 199--70%, cattle serum--20%, chicken embryo extract--10%, glucose--400 mg/100 ml, vitamin "C"--7 mg/100 ml, benzilpenicillin--50 U/ml. Three series of experiments were carried out with cultivation of the pancreatic gland of 18, 19 and 20-day-old embryos for 4--28 days. The electronograms obtained demonstrate a certain difference in reactivity, cytophysiology and differentiation of exocrine and endocrine epithelium under the conditions of organic cultivation. During the process, endocrine epithelium undergoes primary differentiation, secondary cytodifferentiation and, further, degenerative changes and necrosis develop. B-cells of the insular apparatus grow and function better than the exogenous epithelium. On the 28th day of cultivation, the embryonic pancreas of 19-day-old embryo demonstrates certain signs of synthesis and B-granule formation. In B-cells cytoplasm, granules of different stages of secrete formation are revealed.