Effects of copper deficiency and copper loading on 67Cu in supernatants of rat organs

Eleven organs of the rat were studied 1 hr and 24 hr after the intravenous administration of 67CuCl2 and 67Cu-ceruloplasmin. The rats were normal, copper-deficient, or copper-laden. The amounts of stable copper and 67Cu in the whole organ and supernatant fractions, corrected for whole blood copper and 67Cu, were measured. The distribution of supernatant 67Cu was determined in three Sephadex G-100 chromatographic zones: Peak I (150,000 daltons), Peak II (31,000 daltons), and Peak III (11,000 daltons). All organs took up 67Cu from both sources, but there was a tendency for increased uptakes in copper-deficient rats and decreased uptake in copper-laden rats. Only lung, heart, and testis took up more 67Cu from 67Cu-ceruloplasmin than from 67CuCl2. Supernatant 67Cu tended to be in Peak I when the source was 67Cu-ceruloplasmin and in Peak II when the source was 67CuCl2. When 67Cu-ceroloplasmin was added to supernatant fractions in vitro, the 67Cu was in Peak I. However, when 67CuCl2 was added to supernatant fractions, Peak III predominated in kidney, brain, testis, and liver; Peak II predominated in none; and Peak I predominated in spleen, muscle, large and small bowel, stomach, lung, and heart. A high-molecular-weight copper-binding substance seems to be present in organ supernatant fractions.