IS COBALT CONCENTRATED IN PANCREATIC ISLET TISSUE?

Abstract

ABSTRACT Radioactive (58Co) cobaltous chloride with stable cobaltous chloride as a carrier, was administered to the marine teleost Cottus scorpius as a single intramuscular injection. The radioactivity of various tissues was measured from 3 h to 10 d after the injections in a scintillation spectrometer. The unique anatomical features of Cottus scorpius – its pancreatic islet tissue is concentrated into two grossly visible structures free from admixture of exocrine pancreatic parenchyma – allow of quantitative determination of the total uptake of radiocobalt in islet tissue and comparison with that of other tissues. This is not possible in mammals. It was found that the isolated islet tissue had approximately the same high ability as the liver to concentrate cobalt at all observation periods after 3 h. Autoradiograms, however, showed only a slight uptake of radiocobalt in the islet tissue. This finding is interpreted as indicating that most of the accumulated cobalt existed in a free soluble form or bound to substances which were dissolved during conventional fixation and embedding procedures preceding autoradiography.