Effect of melatonin on pro-opiomelanocortin mRNA expression in arcuate nucleus of rat hypothalamus.
OBJECTIVE
To observe altered expression of pro-opiomelanocortin (POMC) mRNA localized in neurons in the arcuate nucleus of rat hypothalamus following exogenous administration of melatonin.


METHODS
The experimental animals were divided into two groups injected i.p. with melatonin 90 mg.kg-1 and vehicle at 12 h interval (9:00 am and 9:00 pm). Twelve hours after the last injection, the rat brains were processed for coronal sections and nonradioactive in situ hybridization histochemistry technic was used. The integral optical density (IOD) and mean optical density (OD) of the stained brain sections were measured using the computer-assisted image processing technique.


RESULTS
The POMC mRNA expression in the arcuate nucleus showed obvious enhancement in the brain sections of rats treated with melatonin. The IOD and OD values in the hypothalamic arcuate nucleus area were increased significantly (P < 0.01, P < 0.05 respectively) with melatonin treatment.


CONCLUSIONS
Melatonin may enhance the POMC mRNA expression in the arcuate nucleus of rat hypothalamus.
Yu
C X
CX
State Key Laboratory of Medical Neurobiology, Department of Neurobiology, Shanghai Medical University, Shanghai 200032, China. zjyucx@pub5.fz.fj.cn
Wu
G C
GC
Xu
S F
SF
Chen
C H
CH
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D007033:Hypothalamus, Middle / Q000378:metabolism; D017403:In Situ Hybridization; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D012333:RNA, Messenger; D011333:Pro-Opiomelanocortin; D008550:Melatonin