Effect of some heavy metals on protein and collagen biosynthesis in rabbit dental pulp in vitro

Cadmium, zinc, copper, and mercury, being components of dental alloys, have been tests at concentrations from 20 to 120 micronM for their effect on the incorporation of 14C-proline into various fractions of rabbit dental pulp incubated in vitro. With cadmium and zinc and increased amount of 14C-activity was recovered from the TCA-soluble pool, whereas the further incorporation into total protein and collagen, i.e. 14C-hydroxyproline, was markedly inhivited. Copper and mercury, however, reduced the amount of label in the TCA-soluble fraction. Both metals exhibited a dose-dependent inhibitory effect on the hydroxylation step in collagen synthesis, whereas for mercury only, an inhibition of the general protein synthesis was indicated. With all four metals the proportion of 14C-labeled protein and hydroxyproline recovered from the medium was reduced, the effect being most prominent with cadmium and zinc.