title: Oestradiol decreases melanin-concentrating hormone (MCH) and MCH receptor expression in the hypothalamus of female rats.
abstract: Previous studies have shown that oestradiol (E₂) decreases the orexigenic effect of melanin-concentrating hormone (MCH). In the present study, we examined whether this action of E₂ is mediated by its ability to decrease the expression of MCH or its receptor (MCHR1). Using immunocytochemistry and western blotting, we examined whether E₂ decreases MCH-immunoreactive neurones or MCHR1 protein content in the hypothalamus of female rats. We found that both MCH and MCHR1 protein expression was decreased by acute E₂ treatment in ovariectomised rats, and by the peri-ovulatory increase in circulating E₂ in pro-oestrous rats, relative to rats at other cycle stages. To determine whether these changes in MCH/MCHR1 protein expression may be mediated by E₂'s ability to directly regulate the transcription of MCH and MCHR1 genes, the effect of E₂ treatment on MCH and MCHR1 mRNA expression in a neuronal hypothalamic cell line was examined using real-time reverse transcriptase-polymerase chain reaction. We also determined whether MCH and oestrogen receptor (ER)α are co-expressed in the hypothalamus of female rats. E₂ treatment did not decrease MCH or MCHR1 mRNA expression in vitro, and no hypothalamic neurones were identified that co-expressed MCH and ERα. We conclude that E₂-dependent decreases in hypothalamic MCH/MCHR1 protein expression mediate the ability of E₂ to decrease MCH-induced feeding. The current findings suggest, however, that E₂ exerts these actions indirectly, most likely though interactions with other neuronal systems that provide afferent input to MCH and MCHR1 neurones.
authors: Program in Neuroscience, Florida State University, Tallahassee, FL, USA. jsantoll@buffalo.edu
authors: J
authors: J
authors: Santollo
authors: L A
authors: LA
authors: Eckel
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000502:physiology; D004971:Estrus; D005260:Female; D007028:Hypothalamic Hormones / Q000235:genetics / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D008543:Melanins / Q000235:genetics / Q000378:metabolism*; D010907:Pituitary Hormones / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D060888:Real-Time Polymerase Chain Reaction; D011979:Receptors, Pituitary Hormone / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D047628:Estrogen Receptor alpha; D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; D011979:Receptors, Pituitary Hormone; C092274:melanin-concentrating hormone receptor; D004958:Estradiol; C019463:melanin-concentrating hormone