title: Negative energy balance in dairy cows is associated with specific changes in IGF-binding protein expression in the oviduct.
abstract: Negative energy balance (NEB) during early lactation in dairy cows leads to an altered metabolic state that has major effects on the production of IGF family members. Low IGF-I concentrations are associated with poor fertility and therefore we aimed to determine whether NEB exerts a direct effect on IGF expression in the postpartum oviduct. Multiparous Holstein cows were allocated to two treatments (each n=6) designed using differential feeding and milking regimes to produce either mild NEB (MNEB) or severe NEB (SNEB). Animals were slaughtered in week 2 of lactation when divergent metabolic profiles were evident. Oviducts were collected for RNA analysis by real-time RT-PCR and in situ hybridisation. Quantitative measures in oviduct gene expression were obtained for all members of the IGF family (IGF-I/II, IGF-binding proteins (IGFBP) 1-6 and receptors for IGF types 1 and 2), insulin A/B, GH, glucocorticoid and oestrogen alpha/beta. Expression of IGFBP-2 and IGFBP-6 (both of which have a high affinity for IGF-II) was decreased in SNEB relative to MNEB (P<0.05). No other gene was altered by NEB, but IGF-II, IGFBP-3, IGFBP-5 and IGFBP-6 all showed differential expression in different regions of the oviduct. These results indicate that, in addition to low circulating IGF-I after calving, NEB may also influence IGF availability in the oviduct indirectly through changes in specific IGFBP expression. It is possible that the predicted increased signalling by IGF-II may perturb embryo development, contributing to the high rates of embryonic mortality in dairy cows.
authors.affiliation: Reproduction, Genes and Development Group, Department of Veterinary Basic Sciences, Royal Veterinary College, London, AL9 7TA, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Fenwick
authors.forename: S
authors.initials: S
authors.lastname: Llewellyn
authors.forename: R
authors.initials: R
authors.lastname: Fitzpatrick
authors.forename: D A
authors.initials: DA
authors.lastname: Kenny
authors.forename: J J
authors.initials: JJ
authors.lastname: Murphy
authors.forename: J
authors.initials: J
authors.lastname: Patton
authors.forename: D C
authors.initials: DC
authors.lastname: Wathes
mesh_terms: D000818:Animals; D001345:Autoradiography; D002417:Cattle / Q000378:metabolism*; D003612:Dairying; D004734:Energy Metabolism; D005187:Fallopian Tubes / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D005313:Fetal Death; D015870:Gene Expression; D017403:In Situ Hybridization / Q000379:methods; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000032:analysis / Q000378:metabolism; D018976:Insulin-Like Growth Factor Binding Protein 6 / Q000032:analysis / Q000378:metabolism; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D007774:Lactation / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D011986:Receptors, Somatotropin / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000502:physiology
chemical_list: D018971:Insulin-Like Growth Factor Binding Protein 2; D018976:Insulin-Like Growth Factor Binding Protein 6; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II