Effects of irradiation on the sensitivity of melatonin release to norepinephrine in cultured pineal bodies of rats.
We measured levels of basal and norepinephrine (NE) -induced melatonin release in cultured pineal bodies of rats just after and 2 days after irradiation (20 or 200 Gy) or sham-irradiation. On the day of irradiation, basal and NE-induced melatonin release were not affected by irradiation. Two days after irradiation, basal melatonin levels in both irradiated groups were significantly lower than those in control group, whereas NE-induced melatonin levels in the irradiated groups were higher than those in the control group. These results suggested that irradiation decreases basal melatonin synthesis in pineal glands but that melatonin response to NE is increased after irradiation.
Saito
K
K
Department of Physiology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan.
Shinohara
K
K
Morofushi
M
M
Funabashi
T
T
Mitsushima
D
D
Hata
M
M
Matsubara
S
S
Kimura
F
F
D000316:Adrenergic alpha-Agonists / Q000378:metabolism* / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism* / Q000494:pharmacology*; D010870:Pineal Gland / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D000316:Adrenergic alpha-Agonists; D008550:Melatonin; D009638:Norepinephrine