EFFECTS OF LOW-FREQUENCY ELECTROMAGNETIC-FIELDS ON THE ACTIVITY OF ORNITHINE DECARBOXYLASE IN DEVELOPING CHICKEN EMBRYOS

In another paper we have reported the results of a study involving ove r 2500 chick embryos, in which time-varying magnetic fields (MFs) were shown to induce morphological abnormality. In an attempt to understan d the mechanism by which these abnormalities arise, the present work e xplores the effects of weak magnetic fields (MFs) on the activity of t he growth related enzyme ornithine decarboxylase (ODC) in chick embryo s. The results presented here demonstrate that a 4 mu T, 60 Hz sinusoi dal magnetic field significantly enhances ODC activity during gastrula tion, and diminishes ODC activity during neurulation. In another set o f experiments, slightly older embryos were analyzed for gross morpholo gy. The abnormality rate among MF-exposed embryos was approximately th ree times that of control embryos - with the vast majority of malforma tions being neural tube abnormalities. When embryos with morphological abnormalities were assayed separately from those which were morpholog ically normal, it was found that the ODC activity in the abnormal grou p was significantly less than that in the normal group. However, compa rison of normal control embryos with normal MF exposed embryos showed no differences in ODC activity. Similarly comparison of abnormal contr ol embryos with abnormal MF-exposed embryos showed no differences in t he ODC activity. We speculate that MF-induced ODC alterations during n eurulation may be related to the occurrence of MF-induced neural tube abnormalities at later stages of development. (C) 1997 Elsevier Scienc e S.A.