Glucose homeostasis in rats exposed to magnetic fields.

The development of diagnostic and therapeutic applications of magnetic fields, especially with regard to magnetic resonance imaging (MRI), draws attention to accompanying possible adverse effects. Recent investigations revealing an increase in insulin release in diabetic rats, increase in glycogen, and decrease in glucose level in rats exposed to magnetic fields, have provided the stimulus for the current studies. Rats were exposed to uniform constant magnetic fields of 10(-3) T and 10(-2) T, 1 hour each day, for a period of ten days. Blood glucose slightly increased, the release of insulin decreased, and the glucagon content increased when compared with controls. The efficiency of the hypophysis-hypothalamic system changed, as indicated by an increase in the level of growth hormone and thyroid-stimulating hormone. The content of the thyroid hormones, triiodothyronine and thyroxine, was higher between the third and seventh day of exposure. An increase in the cortisol level was also observed. The results might implicate a temporarily diabetic-like response in rats exposed to the magnetic field.

Structural and functional changes in organelles of liver cells in rats exposed to magnetic fields.

Exposure of rats to magnetic fields of 10(-3) and 10(-2) T for 1 hr daily generated structural changes in hepatocytes mitochondria, endoplasmic reticulum, and ribosomes. Simultaneously there was an increase in the activities of the mitochrondrial respiratory enzymes: NADH dehydrogenase, succinic dehydrogenase, and cytochrome oxidase. The extent of the changes in liver cell properties following exposure depend on the duration of exposure to and the strength of the applied magnetic fields. Ultrastructural studies did not reveal any changes in external membranes of hepatocytes or in the membranes of cell nuclei. An increase in the amount of glycogen in hepatocytes of rats exposed to both 10(-3) and 10(-2) T was noted. The high level of cortisol in serum of exposed rats suggests that magnetic field may be a stress generating factor.

Effect of static magnetic field on some enzymes activities in rats.

The magnetic field of 0.008 T and 0.15 T inductions influence lasting 7 weeks (7 days a week), 1 h daily determines the increase of the activity of cytoplasmatic enzymes (glutamic pyruvic transaminase, glutamic oxalacetic transaminase, lactic dehydrogenase), the decrease of cholinesterase activity and the growth of alkaline phosphatase activity in the plasma of the examined animals. The observed changes were reversible. 2 months after the exposure had been stopped, the tested parameters were back to normal.

Effect of chronic exposure to static magnetic field upon the serum glutamic pyruvic transaminase activity GPT and morphology of the cardiac muscle, skeletal muscles, kidneys, cerebellum and lung tissue in guinea pigs.

In a cycle of investigations concerning the pathogenesis of functional changes caused by the influence of magnetic field of induction occurring in laboratory and industrial conditions glutamic pyruvic transaminase activity in external blood and morphological picture of cardiac muscle, skeletal muscles, kidneys, cerebellum and lung tissue in guinea pigs were examined. Static homogeneous magnetic field as low as 0.005 T produced a statistically significant decrease in GPT activity. The animals were exposed to the magnetic field action for seven weeks 1 hour a day, 7 days a week. The range of observed changes of enzyme activity were determined by the duration of magnetic field. No morphological changes were observed.

Effect of chronic exposure to static magnetic field upon the K+, Na+ and chlorides concentrations in the serum of guinea pigs.

The magnetic field influence on the concentration of serum K+, Na+ and chlorides was tested. The guinea pigs were exposed to the static magnetic field for six weeks 1 hour a day, 7 days a week. Magnetic field of induction 0.005 T--0.3 T produced progressively an increase in Na+ concentration and a decrease in chlorides concentration in the serum. The range of observed changes was dependent on the duration of exposure to the magnetic field. No change in K+ serum concentration was observed following magnetic field exposure.

Effect of magnetic field on the process of cell respiration in mitochondria of rats.

Exposure of rats to static magnetic field 1 hour daily for a period of 7 weeks (7 days a week) leading to disturbances of the respiration processes in the mitochondria of liver cells. The rate of respiration through NADH dehydrogenase, succinic dehydrogenase and cytochrome oxidase was dependent on both the duration and the intensity value of the field applied. The animals showed greater sensitivity to the action of a 0.008 T magnetic induction field than to that of 0.15 T. The observed changes were reversible after 3 months since the everyday exposure had been stopped.

Activity of acid and alkali phosphatase in guinea pigs exposed to the static magnetic fields.

The influence of static homogeneous magnetic field on alkali and acid phosphatase in guinea pigs (regarding the twenty four hours rhythm) was studied. The increase of acid phosphatase activity was determined by the time of exposure to magnetic field. No changes in alkali phosphatase activity were observed.

The effect of static magnetic field on protein concentration in serum of guinea-pigs.

The influence of the static magnetic field on magnetic induction 0.005 T--0.3 T on the protein concentration in serum of guinea-pigs with regard of twenty four hours rhythm was investigated. The range of occurrenced changes were determined by the duration of the static homogeneous magnetic field.

The effect of magnetic fields on platelets, blood coagulation and fibrinolysis in guinea pigs.

Exposure of guinea pigs to homogeneous magnetic fields as low as 0.005 T for 1 hour, 7 days a week, for 6 weeks led to a decreased platelet count; increased platelet aggregation; increased prothrombin and partial thromboplastin times; decreased fibrinogen and increased fibrinolysis. These effects were reversible within 2 months of discontinuation of exposure to the magnetic field. These results suggest an extensive hemorrhagic diathesis combined with a tendency toward thrombosis. Possible mechanisms are discussed.

Effect of magnetic field on activity of cytochrome oxidase not moved or moved relative to magnetic field lines.

The influence of constant homogeneous magnetic fields (700 to 13,000 gauss) on cytochrome c oxidase activity as a function of strength and duration of magnetic field and as a function of enzyme concentration at 0-5 degrees C in solution was measured on samples not moved or moved relative to the magnetic field lines. Increases or decreases of enzyme activity were observed depending on whether or not the samples were so moved. These changes persisted for hours after terminating exposure to the magnetic field.

Effect of deterlon (DBS) on the electrocardiogram of eel Anguilla anguilla (L).

Effect of Deterlon (DBS) on the electrocardiogram of eel Anguilla anguilla (L). Acta Physiol. Pol. 1977, 28 (2): 179--186. The investigations of the effect of a detergent Deterlon-DBS present in industrial and community sewage on ECG changes in the eel Anguilla anguilla (L) showed that it causes disturbances in the impulse-generating centres and in the mechanism of impulse conduction in the heart. It was found that the threshold concentration of Deterlon-DBS in aqueous medium is 3 mg SA/1 for the eel, the lethal concentration lying in the range of 60--100 mg SA/1.