Influence of certain metals on the level of metallothionein-like proteins in the liver and kidneys of rats.

Rats were given certain metal salts once every other day for six to eight doses and therafter the levels of metallothionein-like proteins (MTP) were determined in their liver and kidneys. The normal level of those proteins ranged from 0.1 to 0.4 mg/g in the liver and 0.2 and 0.6 mg/g in the kidney. Beryllium, magnesium, barium, strontium, tin, arsenic, selenium, chromium, and nickel administration did not influence the tissue levels of MTP. There was a tendency toward increased MTP levels in the liver after the application of high doses of iron. A significant increase in MTP levels in the liver resulted from cobalt administration and in the kidneys of bismuth-treated rats. Applying molecular filtration it was shown that both metals were partially bound in vivo to protein fractions, the molecular weights of which are close to that of metallothionein.