DISTRIBUTION OF HEAVY-METALS AND THEIR ULTRAHISTOCHEMICAL DETERMINATION IN THE ORGANS OF CALVES

The distribution of Cd, Zn, Se and Cu in the tissues of animals receiv ing different total doses of these metals for different time periods w as studied at the submicroscopical level. In experiment I, 32 calves o f both sexes were given heavy metals singly (Cd and Zn) or in combinat ion (Cd, Zn; Cd, Se) from 2 to 14 weeks of age. Experiment II included 21 bulls which received Cd, or Cd and Cu or Cd and Zn in a diet from 3 to 15 months of age. For ultrahistochemical examination, samples of liver, kidney, pancreas, testis or ovary and diaphragm were collected in experiment I and those of liver, kidney, pancreas and testis in exp eriment II. The ultrahistochemical method used was based on the detect ion of metal sulphides using a hydroquinone developer with silver nitr ate added. The foci of reduced silver on sulphide molecules were ident ified as dark granules in cell cross-sections. In experiment I, after combined administration of Cd and Zn, the highest amounts of reduced s ilver granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were foun d in glandular cells of the pancreas. Administration of Cd and Se resu lted in the presence of large numbers of granules in the nuclei and nu cleoli of spermatogonies. In experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucle oli, nuclei and cytoplasm of cells in testes, kidneys and pancreas. Fo llowing Cd intake, the highest accumulation of granules was observed i n the nucleoli of hepatocytes and cells of the proximal and distal ren al tubules. Combined Cd and Cu produced the highest numbers of granule s in cells of the proximal and distal renal tubules and in the nucleol i and nuclei of germinal epithelium.