Developmental changes in the hypothalamic mRNA levels of prepro-orexin and orexin receptors and their sensitivity to fasting in male and female rats.
Orexin, which is also called as hypocretin (Hcrt), a product of the prepro-orexin (pp-orexin//Hcrt) gene, affects various physiological and behavioral functions, such as the sleep-wake cycle and appetite. The developmental changes in the hypothalamic mRNA levels of pp-prexin and the orexin receptors OX1R and OX2R and their sensitivity to fasting were evaluated in both male and female rats. During development, hypothalamic pp-orexin/Hcrt mRNA expression increased in both male and female rats, whereas hypothalamic OX1R mRNA expression decreased in both sexes. In addition, hypothalamic OX2R mRNA expression increased in male rats, but did not change in female rats. Fasting did not affect hypothalamic pp-orexin/Hcrt mRNA expression in either sex. Hypothalamic OX1R mRNA expression was increased by fasting in the prepubertal period (postnatal days 20 and 30) in female rats, but was not affected by fasting in males. In male rats, hypothalamic OX2R mRNA expression was decreased by fasting during the neonatal period (postnatal day 10), but not the prepubertal period (postnatal days 20 and 30). In females, hypothalamic OX2R mRNA expression was also decreased by fasting; however, the fasting-induced downregulation of hypothalamic OX2R expression persisted until postnatal day 20. These results indicate that the developmental patterns of components of the orexin system and their sensitivity to fasting during the neonatal and prepubertal periods only differ slightly between the sexes. These differences might be involved in the development of some physiological and behavioral functions.
Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan. Electronic address: iwasa.takeshi@tokushima-u.ac.jp.
Takeshi
T
Iwasa
Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan.
Toshiya
T
Matsuzaki
Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan.
Munkhsaikhan
M
Munkhzaya
Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan.
Altankhuu
A
Tungalagsuvd
Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan.
Akira
A
Kuwahara
Department of Reproductive and Menopausal Medicine, Institute of Biomedical Sciences, Tokushima University Graduate School, Japan.
Toshiyuki
T
Yasui
Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima 770-8503, Japan.
Minoru
M
Irahara
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D005215:Fasting; D005260:Female; D007031:Hypothalamus / Q000254:growth & development* / Q000378:metabolism*; D008297:Male; D064446:Orexin Receptors / Q000235:genetics / Q000378:metabolism*; D000068797:Orexins / Q000235:genetics / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012727:Sex Characteristics
D064446:Orexin Receptors; D000068797:Orexins; D012333:RNA, Messenger
Development; Hypothalamus; pporexin