Effects of estrogen on the expression of connexin32 and connexin43 mRNAs in the suprachiasmatic nucleus of female rats.
The suprachiasmatic nucleus of the hypothalamus (SCN) is the site of the endogenous biological clock that regulates circadian rhythms in mammals. It has been shown that the gap junction couples neurons in the rat SCN. To determine the effects of estrogen on gap junction communication in the SCN, we examined the effects of estrogen on the expression of connexin32 and connexin43 mRNAs in the SCN and cerebral cortex (CX) of female rats. Ovarectomized adult rats were injected with 20 microg of 17beta-estradiol and killed 24 h after the treatment. Northern blot revealed that the expression of connexin32 mRNA was significantly increased in the SCN but not in the CX. On the other hand, estrogen increased the connexin43 mRNA level in the CX but not in the SCN. These results suggest that the gap junction with connexin32 is specifically regulated by estrogen in the SCN of female rats.
Shinohara
K
K
Department of Physiology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan. kazuyuki@med.yokohama-cu.ac.jp
Funabashi
T
T
Mitushima
D
D
Kimura
F
F
D000818:Animals; D015152:Blotting, Northern; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D018031:Connexin 43 / Q000235:genetics*; D017630:Connexins / Q000235:genetics*; D004967:Estrogens / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D017629:Gap Junctions / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D012333:RNA, Messenger / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013493:Suprachiasmatic Nucleus / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D000097002:Gap Junction beta-1 Protein
D018031:Connexin 43; D017630:Connexins; D004967:Estrogens; D012333:RNA, Messenger; D000097002:Gap Junction beta-1 Protein