Content of eight elements in rat foetal pancreatic islets by neutron activation analysis

Iron and zinc, essential elements for human body are detected in much highe r concentration than any other elements (Rb, Cs, Sc, Cr, Co and Se) by neut ron activation analysis in rat pancreatic islets after different times of i n vitro culture. The physiological function of iron is adscribed to the red ox potential reaction at the biochemical and metabolic level to obtain ener gy in active secretory processes in the cells, and forming part of importan t proteins one of which is ferritine, an iron accumulative protein also pre sent in pancreatic islets. Zinc in Langerhans islets has an essential role in the synthesis and function of insulin and forming part of metallothionei n. The concentration of both elements Zn and Fe are found as high as 124 an d 105 mg/kg dry weight respectively, in experiments using 20 pancreatic isl ets. One pancreatic islet corresponds to 1+/-0.3 mu g protein. The increase of iron and zinc in function of time during incubation of the foetal rat pancreatic islet corroborates in this work the continuous rise o f insulin content during the late fetal and early neonatal periods in the r at pancreatic islets. Moreover, the reported results of the increase of the se bivalent essential cations, corresponds with the increase of the known h ormonal content, its basal release and with the response to glucose, using the fetal rat islets cultured in vitro. The gradient of other elements concentration are diminishing from Rb>Se>Cr> Co>Cs>Sc. Rubidium it is known kinetically as interchangeable element with potassium in the pancreatic islets. Selenium, chromium and cobalt are consi dered essential elements participating in numerous enzimatic defense and me tabolic reactions but the changes between these last six elements, also det ermined in this work are not significant enough to reveal important biochem ical events, as for instance for chromium related to the glucose tolerance factor.