Oncostatic action of melatonin[10(-10) M]is exerted through modulation of the levels of gap junctional intercellular communication. Also, the data indicate that ELF-MF could counteract the melatonin-induced enhancement of junctional transfer.

Melatonin,(10(-9)M) added to the culture medium, increased the duration of the cell cycle of human breast cancer cells, delaying the entry into mitosis.

Effects of light and electromagnetic fields (EMFs) could have implications for long-term risk of breast cancer, peak levels may be consistent with those thought to suppress melatonin.

Associations between EMF exposure, breast cancer and modifications of melatonin secretion could be a biologic signal of these effects.

Light and EMF effects on melatonin; melatonin effects on breast cancer.

Results support an association between work as a radio and telegraph operator and breast cancer for disturbances of chronobiological parameters.

Nocturnal serum melatonin determination at 50 microT did not yield significant differences.

Melatonin (1nM) antiproliferative effects could be mediated by a reduction of DNA synthesis.

50-Hz, 100-mG MF significantly decreases circulating melatonin but is not associated with a development of DMBA-induced mammary tumors.

No abstract available.