Thymidine Kinase and DNA Polymerase Activity in Normal and Zinc Deficient Developing Rat Embryos

Summary

Thymidine kinase and DNA polymerase activities were significantly (P < 0.05 and P < 0.01, respectively) lower in 9, 10, 11, and 12-day embryos taken from dams fed a zinc deficient diet than in those from ad libitum fed and restricted intake controls. An additional finding was that of increased activity of both thymidine kinase and DNA polymerase with increasing age of embryos. As previously found with thymidine kinase, addition of zinc and other divalent metal ions in vitro had little effect on restoration of DNA polymerase activity from zinc deficient extracts when added at concentrations of 0.01 and 0.05 mM. When added at a level of 0.2 mM, zinc, but not other metal ions, had an inhibitory effect on DNA polymerase activity. These findings support the hypothesis that the teratogenic effects of zinc deficiency are associated with the enzymes involved in DNA synthesis.

This research was supported in part by NIH Research Grant No. HD-01743 from the National Institute of Child Health and Human Development.