[Changes in monoamine concentrations in developing female rat brains under continuous light].
Norepinephrine (NE), dopamine (DA) and serotonin (5-HT) concentrations in the hypothalamus were measured by HPLC on days 10, 20, 30 and 40 of age in Sprague-Dawley albino female rats after continuously exposed to light (LL). When rats were housed under a lighting schedule (14hr light and 10hr dark: LD), the NE concentration increased linearly. The DA concentration remained lower on days 10, 20 and 30 of age, but a sudden increase in the DA concentration appeared on day 40 of age. An increase in the 5-HT concentration occurred at day 20 of age, and remained at the same level thereafter. LL exerts profound effects on DA and 5-HT concentrations in the hypothalamus; an increase in the 5-HT concentration appeared at day 10 of age, and the peak concentration of DA was reached at day 30 of age. The inference is then that LL exerts effects on the metabolism of 5-HT and DA and promotes the increase in 5-HT and DA concentrations in the hypothalamus, and that the advanced appearance of 5-HT and DA in the hypothalamus seems to correspond with the advancement of puberty onset. Indeed, LL exerted its effects on puberty onset and advanced it.
Ohkura
T
T
Department of Obstetrics and Gynecology, Koshigaya Hospital, Dokkyo University School of Medicine, Saitama.
Hagino
N
N
Yaoi
Y
Y
D000818:Animals; D004298:Dopamine / Q000032:analysis*; D005260:Female; D007031:Hypothalamus / Q000737:chemistry*; D008027:Light; D009638:Norepinephrine / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000032:analysis*
D012701:Serotonin; D004298:Dopamine; D009638:Norepinephrine