NEONATAL RAT ISLETS OF LANGERHANS AND FETAL-RAT PANCREAS - ISOLATION,IMMUNOHISTOCHEMICAL, FUNCTIONAL, AND AUTORADIOGRAPHIC EVALUATION

The aim of this study was to develop an optimal isolation technique fo r neonatal rat islets of Langerhans, to perform functional evaluation in vitro, to evaluate immunohistochemically isolated rat islets and fe tal rat pancreata after a variable period of culture, and to study gro wth potentials by means of autoradiography. The islets were isolated u sing minor modifications of standard procedures including collagenase and DNase, Islets were separated on a discontinuous Percoll gradient, The maximum yield of islets amounted to 240 per pancreas. Fetal pan cr eata from rats were cultured under similar conditions as neonatal isle ts to compare their insulin secretory capacity after different periods of culture, The insulin secretion increased gradually, and isolated i slets achieved a similar secretion potential to adult rat islets. The mitotic activity of both islets and fetal pancreata was confirmed usin g tritiated thymidine. The isolation procedure was found suitable for producing well-functioning islets, which could be kept in culture for a period of about 1 month without deterioration in their insulin secre tory capacity. The gradual increase in insulin secretory capacity of i slets and fetal pancreata was due, in part, to hyperplasia and not jus t hypertrophia. Autoradiographical evaluation revealed a high mitotic activity after culture, in particular of fetal pan creata. Fetal pancr eata cultured for about 10 days showed a phenomenon of budding endocri ne cells at the organ surface, A high mitotic activity was found in th ese buds.