title: Circularly polarized 50-Hz magnetic field exposure reduces pineal gland and blood melatonin concentrations of Long-Evans rats.
abstract: In order to determine if pigmented rats also exhibit melatonin suppression like that described for albino rats exposed to circularly polarized, 50-Hz, 1-muT magnetic fields for 6 weeks, two experiments were conducted with Long-Evans rats. The field-exposed experimental group received circularly polarized, 50-Hz, 1-muT magnetic fields for 6 weeks, the concurrent sham-exposed control group was exposed to the stray field of 0.02 muT. In addition, prior to the exposure experiment, two cage-control groups were placed in the facility for 6 weeks without activation of the 50-Hz magnetic field generation apparatus. Rats were sacrificed at 12.00 and at 24.00 h for collection of plasma and pineal gland: melatonin was determined by radioimmunoassay. Significant reductions of plasma and pineal gland melatonin contents were observed at 0.02 muT as compared to the control values, and a further reduction was observed at 1 muT. As do albino rats, pigmented rats rats also exhibit melatonin suppression when exposed to time-varying magnetic fields.
authors.affiliation: Department of Physiology, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Honma
authors.forename: T
authors.initials: T
authors.lastname: Shigemitsu
authors.forename: Y
authors.initials: Y
authors.lastname: Shiga
mesh_terms: D000818:Animals; D004574:Electromagnetic Fields; D008297:Male; D008550:Melatonin / Q000096:biosynthesis* / Q000097:blood; D010870:Pineal Gland / Q000378:metabolism / Q000502:physiology*; D011863:Radioimmunoassay; D051381:Rats; D013997:Time Factors
chemical_list: D008550:Melatonin