Effects of low frequency electromagnetic fields on the activity of ornithine decarboxylase in developing chicken embryos

Abstract In another paper we have reported the results of a study involving over 2500 chick embryos, in which time-varying magnetic fields (MFs) were shown to induce morphological abnormality. In an attempt to understand the mechanism by which these abnormalities arise, the present work explores the effects of weak magnetic fields (MFs) on the activity of the growth related enzyme ornithine decarboxylase (ODC) in chick embryos. The results presented here demonstrate that a 4 μT, 60 Hz sinusoidal magnetic field significantly enhances ODC activity during gastrulation, and diminishes ODC activity during neurulation. In another set of experiments, slightly older embryos were analyzed for gross morphology. The abnormality rate among MF-exposed embryos was approximately three times that of control embryos — with the vast majority of malformations being neural tube abnormalities. When embryos with morphological abnormalities were assayed separately from those which were morphologically normal, it was found that the ODC activity in the abnormal group was significantly less than that in the normal group. However, comparison of normal control embryos with normal MF exposed embryos showed no differences in ODC activity. Similarly comparison of abnormal control embryos with abnormal MF-exposed embryos showed no differences in the ODC activity. We speculate that MF-induced ODC alterations during neurulation may be related to the occurrence of MF-induced neural tube abnormalities at later stages of development.