Visfatin is present in bovine mammary epithelial cells, lactating mammary gland and milk, and its expression is regulated by cAMP pathway.
Visfatin was originally identified as a growth factor for immature B cells, and recently demonstrated to bind insulin receptor. Visfatin mRNA and protein were detected by RT-PCR and Western blot analysis in cloned bovine mammary epithelial cells, lactating bovine mammary gland and human breast cancer cell line, MCF-7. Immunocytochemical staining localized the visfatin protein in the cytosol and nucleus of both cells. Quantitative-RT-PCR analysis revealed that the expression of the visfatin mRNA was significantly elevated when treated with forskolin (500 microM), isopreterenol (1-10 microM) and dibutyric cyclic AMP (1 mM) for 24 h, and significantly reduced when treated with insulin (5-50 ng/ml) and dexsamethasone (0.5-250 nM) for 24 h. These results indicate that mammary epithelial cells express the visfatin protein and secrete them into the milk.
Yonezawa
Tomo
T
Department of Animal Physiology, Graduate School of Agricultural Science, Tohoku University, Amamiyamachi, Sendai 981-8555, Japan. yonet@bios.tohoku.ac.jp
Haga
Satoshi
S
Kobayashi
Yosuke
Y
Takahashi
Tatsuyuki
T
Obara
Yoshiaki
Y
D024506:5' Flanking Region / Q000235:genetics; D051698:Activating Transcription Factor 2 / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D000242:Cyclic AMP / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics; D016207:Cytokines / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects; D005260:Female; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007774:Lactation / Q000187:drug effects / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000166:cytology* / Q000187:drug effects; D008892:Milk / Q000737:chemistry*; D008969:Molecular Sequence Data; D010121:Oxytocin / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015854:Up-Regulation / Q000187:drug effects
D051698:Activating Transcription Factor 2; D017362:Cyclic AMP Response Element-Binding Protein; D016207:Cytokines; D007328:Insulin; D012333:RNA, Messenger; D010121:Oxytocin; D003907:Dexamethasone; D000242:Cyclic AMP