Uptake of 65Zn in tapetum lucidum

The uptake of 65Zn (administered as 65ZnCl2) in the tapetum lucidum of ferrets was studied by whole-body autoradiography. The results showed a slow increase in the labelling of the tapetal cells and 7 days after the 65Zn-injection this tissue contained the highest radioactivity in the body. The strong tapetal labelling was registered in both albino and pigmented animals. Previous biochemical and histochemical studies have indicated that there is a specific localization of zinc in the tapetal cells and the results of the present experiments support these reports. There is evidence of a slow turnover of zinc in tissues with large endogenous zinc pools and this also appears to be the situation with the tapetal zinc.