Induction of metal binding proteins in striped bass, Morone saxatilis, following cadmium treatment

Abstract

1. 1. The time course of induction of cytosolic metal binding proteins (MBP) was observed following up to three daily intramuscular injections of cadmium chloride (0.2 mg cadmium/injection). 2. 2. Low molecular weight binding proteins were resolved by gel permeation chromatography on Sephadex G-75. Based on total metal binding capacity, the concentration of crude MBP increased 2.6 fold. This level of induction of MBP was confirmed by polarographic analysis. 3. 3. Initial binding of cadmium to MBP resulted in displacement of zinc, while at later times, zinc associated with MBP increased above control levels. 4. 4. Using 35S-cysteine incorporation, it was shown that the rate of hepatic MBP synthesis was significantly greater than controls and sham injected fish 18 hr after the third cadmium injection. 5. 5. Due to interfering proteins of molecular weights similar to the metal binding proteins one dimensional PAGE was not capable of verifying induction. However, the metal binding proteins were resolved using two dimensional gel electrophoresis.