WEAK (5 MT) STATIC MAGNETIC-FIELD STIMULATES LIPID-PEROXIDATION IN ISOLATED RAT-LIVER MICROSOMES IN-VITRO

The aim of the present study was to test whether relatively weak stati c magnetic fields can modulate lipid peroxidation in membranous subcel lular structures. Rat liver microsomal fraction was isolated by ultrac entrifugation (105,000 g for 60 min) and liver peroxide levels in the fraciton were expressed as thiobarbituric-acid-reactive substances (TE ARS). For the experiments, 2 samples of liver microsomal fractions wer e prepared from each rat; one sample was exposed for 40 min at 37 degr ees C (water bath) in a 5-mT static magnetic field (SMF) (pair of Helm holtz coils, diameter 35 cm), while the other was kept in a water bath at natural magnetic field (MF) (about 50 mu T) and used for compariso n with the exposed sample. Following exposure in the magnetic field, T EARS levels were determined in both samples tin triplicate). Eighteen rats (3 sets of experiments, 6 rats per experiment) were used for the study. Of the 18 rat-liver microsomal fractions exposed in the magneti c field (MF), 17 showed higher TEARS levels than did unexposed fractio ns. The difference between each pair of fractions (exposed vs, unexpos ed) ranged from 1.1% to 12.2% (mean: 6.7 +/- 3.9%), and was significan t (t = 7.68, p <.001), when analyzed with a paired t test. From the re sults obtained, we conclude that exposure to a relatively weak SMF sti mulates lipid peroxidation in biological membranes. This phenomenon ma y result in functional alterations of the membranes, but more has to b e known about thresholds of the influence of MFs on lipid peroxidation .