Developmental effects of magnetic field (50 Hz) in combination with ionizing radiation and chemical teratogens.

The influence of a 50 Hz magnetic field (MF) on avian and mammalian embryogenesis, the MF level and vector, as well as the effect of exposure to MF (50 Hz, 10 mT) in combination with X-rays has been recently reported [2,3]. No significant alterations of chick or rat embryogenesis were found after repeated exposures to 50 Hz MF at 10 mT or 6 microT or with different vectors. However, X-ray chick embryotoxicity was significantly affected by repeated exposures of developing organisms to MF. A strong dependence of effect on the type of interaction was revealed. A decrease of X-ray induced teratogenicity was observed when MF preceded X-ray exposure (indirect interaction), while MF exposure applied immediately after X-ray radiation (direct interaction) non-significantly potentiated adverse developmental effects of ionizing radiation. This study deals with the effects of MF in combination with insulin or tetracycline. Exposure of chick embryos to MF influenced the sensitivity of embryonic morphogenetic systems to the subsequently administered chemical teratogens, insulin and/or tetracycline. A protective effect of MF was detected similarly as in the case of indirect interaction with ionizing radiation.

Effect of prenatal and postnatal exposure to lead on kidney function in male and female rats.

The effect of 5 months' exposure to 0.5% lead acetate in drinking water on the kidney function of developing rats was studied. In both sexes, lead exposure produced a significant elevation of the kidney weight and after 3 months' treatment both male and female rats showed signs of tubular impairment. In male rats increased beta 2-microglobulin and lactate dehydrogenase excretion was observed. Lysozyme was increased after 5 months of exposure. No changes were observed in total proteins and albumin excretion. Female rats showed a significantly increased excretion of beta 2-microglobulin from 3 months onwards, while lactate dehydrogenase increased only at the end of 3 months and total proteins after 5 months of exposure. No changes were observed in lysozyme and albumin excretion. Thus, the results suggest that lead exposure produces changes in the renal tubular function of developing rat. There is no sex difference in the nephrotoxicity of lead. Comparison with our previous studies suggests that exposure to lead starting at weaning is more renotoxic than exposure starting 2 months later. However, prenatal exposure might also have been a contributory factor.

Study of the effects of 50 Hz magnetic field on embryonic development: dependence on field level and field vector.

We studied the influence of power frequency and vector of EMF on avian and mammalian embryogenesis at a high level of magnetic induction (10 mT professional exposures and using therapeutic devices of Czech provenance) and at a low level (6 microT-environmental occurrence). No significant alterations of either avian or mammalian embryogenesis were found after repeated exposures to 50 Hz MF at 10 mT or 6 microT, nor with different vectors.

Influence of chronic lead exposure on hormone levels and organ weights in developing rats.

The effect of 5 months' exposure to 0.5% lead acetate in drinking water on the hypothalamo-pituitary-thyroid-adrenal system was evaluated by measuring hypothalamic and striatic noradrenaline (NA), serum thyroxine (T4), 3,5,3'-triiodothyronine (T3) and corticosterone (CS) and blood and adrenal catecholamines (CA) levels in developing rats of both sexes. Blood CA were increased and hypothalamic and striatic NA was decreased by exposure in male rats. In female rats, blood and adrenal CA and serum CS were increased and hypothalamic and striatic NA was decreased by exposure. No changes in the two sexes were observed in serum T3 and T4. Exposure induced an increase in spleen and kidney weights in both sexes; the weight of liver was increased only in female rats. Weights of hypothalamus, striatum, adrenals and thyroid glands were not changed. Female but not male rats exposed to lead gained less weight than controls. The results suggest a non-specific stress response in female rats. In male rats only the sympatho-adrenal system seems to be affected by this lead exposure.

Stress reaction in developing rats exposed to 1% lead acetate.

Effects of a three-month exposure of both male and female rats under their development to lead acetate in drinking water on the hypothalamus-pituitary gland-thyroid gland-suprarenals and sympathico-adrenal systems were evaluated by determining noradrenaline (NA) in the hypothalamus and striatum, thyroxine (T4), 3,5,3'-tri-iodothyronine (T3) and corticosterone (CS) in the serum and catecholamines (CA) in both blood and suprarenals. NA in the hypothalamus and striatum was decreased in exposed males. CA in blood and suprarenals and CS in the serum were increased and NA decreased in the hypothalamus and striatum in exposed females. No serum T3 and T4 changes were found in males or females. The exposure to lead resulted in increased weight of spleen and kidneys in both sexes and suprarenals in females only. Weights of hypothalamus, striatum, liver and thyroid gland did not change. Female rats exposed to lead grew more slowly than control animals. Retardation in the growth was not statistically significant in males. The results indicate a specific stress reaction in female rats. In males only the sympathico-adrenal system seems to be affected by such lead exposure.