Characterization and development of metallothionein in fetal forelimbs, brain and liver from the mouse

The presence of the low molecular weight protein metallothionein (MT) has been investigated in fetal forelimbs, brain and liver from the mouse with the aim of using the protein as a biochemical marker for the early recognition of potential teratogenic agents in the future. Forelimbs, brain and liver were taken from mouse fetuses at ages ranging from 12 to 18 d. Each type of organ was homogenized and centrifuged at 9000 x g. The analysis of MT in the supernatants (S9) with the Cd-heme saturation method detected in all three cases the presence of a low molecular weight, Cd-binding protein whose concentration increased with the age of the fetus. Analysis of the S9 fractions using gel- and anion exchange-chromatography and polyacrylamide gel electrophoresis demonstrated the existence of a protein analogue to the hepatic MT in forelimbs and brain.