title: Growth hormone and lactogenic hormones can reduce the leptin mRNA expression in bovine mammary epithelial cells.
abstract: Leptin mRNA is expressed in not only adipocytes but also mammary epithelial cells and leptin protein is present in milk. Although milk leptin is thought to influence metabolism or the immune system in neonates, there is little information about the regulation of leptin expression in mammary epithelial cells. We examined the effect of growth hormone (GH) and/or lactogenic hormone complex (DIP; dexamethasone, insulin and prolactin) on leptin mRNA expression in mammary epithelial cells. We used a bovine mammary epithelial cell (BMEC) clonal line, which was established from a 26-day pregnant Holstein heifer. We confirmed that the mRNA was expressed in BMECs and the expression was significantly reduced by GH and/or DIP, when the cells were cultured on both plastic plates and cell culture inserts at days 2 and 7 after stimulation with lactogenic hormones. GH and/or DIP significantly increased level of alpha-casein mRNA in BMECs after 7 days on the cell culture inserts, but no mRNA expression was detected at day 2. GH and DIP significantly stimulated the secretion of alpha-casein from BMEC on cell culture inserts at 3.5 and 7 days. However, neither alpha-casein mRNA expression nor secretion was observed in the BMECs cultured on plastic dishes, even in the presence of GH or/and DIP. These results indicate that GH and DIP can directly reduce leptin mRNA expression in both undifferentiated and functionally differentiated bovine mammary epithelial cell.
authors.affiliation: Department of Animal Physiology, Graduate School of Agriculture, Tohoku University, Aoba-ku, Sendai 981-8555, Japan. yones4919@yahoo.co.jp
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yonekura
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Tokushi
authors.initials: T
authors.lastname: Komatsu
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hagino
authors.forename: Kazuo
authors.initials: K
authors.lastname: Katoh
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Obara
mesh_terms: D000818:Animals; D002364:Caseins / Q000235:genetics / Q000378:metabolism; D002417:Cattle / Q000378:metabolism*; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D013006:Growth Hormone / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D020738:Leptin / Q000096:biosynthesis* / Q000235:genetics; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D011388:Prolactin / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D002364:Caseins; D007328:Insulin; D020738:Leptin; D012333:RNA, Messenger; D003907:Dexamethasone; D011388:Prolactin; D013006:Growth Hormone