The effects of low-energy 60-Hz environmental electromagnetic fields upon the growth-related enzyme ornithine decarboxylase.

People living in the industrial society of today are unavoidably exposed to low-energy electromagnetic (EM) radiation. The potential risk to human health of such exposure has received much study. In this regard, numerous epidemiological studies have linked exposure to low-energy EM fields to increased cancer risk. We investigated the ability of low-energy 60-Hz EM fields to alter the activity of ornithine decarboxylase (ODC) in a number of established cell lines. The activity of ODC, the controlling enzyme in polyamine biosynthesis, has been shown to be elevated in growing cells or tissues and during the process of tumor promotion. A 1-h exposure to a 60-Hz EM field of an intensity of 10 mV/cm produced a 5-fold increase in ODC activity in human lymphoma CEM cells and a 2- to 3-fold increase in mouse myeloma cells (P3) relative to the unexposed cultures. Depending upon the cell type, ODC activity increased during the 1-h exposure period and remained elevated for several hours after the field exposure ended. In another series of experiments, fields of an intensity as low as 0.1 mV/cm for a 1-h period produced a 30% increase in the activity of ODC in Reuber H35 hepatoma cells grown in monolayer culture. In the H35 cells, continuous exposure to the 60-Hz EM field (10 mV/cm) for periods of 2 and 3 h resulted in either no increase in ODC activity (2 h) or a decrease in enzyme activity (3 h) compared to the unexposed control cultures. The data is discussed in relation to possible molecular mechanisms of field-cell interaction, the importance of the exposure intervals altering cellular ODC activity and the potential ability of 60-Hz EM fields to serve as a tumor promoting stimulus.