Distribution of Co60, Cu64, and Zn65 in the cytoplasm and nuclei of tissues.

The functions of trace elements in cellular metabolism have been emphasized by various investigators. The stimulating effect of cobalt and copper on the hematopoietic system has been recognized, and the functions of zinc in the enzyme systems have been greatly elucidated by the work of Keilin and Mann (1). Radioactive isotopes of cobalt, copper, and zinc have been used for tracer study by various investigators. Comar (2) recently reviewed the literature dealing with the radioisotopes of trace elements. Some of the essential trace elements appear to exert their action as components of enzyme systems or by stimulating the action of certain enzymes. It seemed reasonable to begin a study of the distribution of trace elements in the cytoplasmic fraction of tissues and compare this with the distribution of the same elements in the nuclear fraction. The data presented below refer to the metabolism of the trace elements cobalt, copper, and zinc in white laboratory mice.