02015naa a2200301 a 450000100080000000500110000800800410001910000180006024500940007826000090017250001430018152010700032465000110139465000140140565000090141965000160142865000150144465300080145965300100146765300280147770000220150570000150152770000180154270000230156070000230158370000180160677300890162418761912018-05-04       2010    bl uuuu     u00u1 u    #d1 aSCHNEIDER, A.  aInsulin-like growth factor and growth hormone receptor in postpartum lactating beef cows.  c2010  aTítulo em português: Fator de crescimento semelhante à insulina e receptor do hormônio do crescimento no pós?parto de vacas de corte.  aThe objective of this study was to evaluate the plasma concentrations of insulin-like growth factor-I (IGF-I), and the mRNA hepatic expression of IGF-I and of the growth hormone receptors GHR and GHR 1A, in postpartum beef cows. Four Angus and four crossbred (Angus x Nelore) postpartum suckled beef cows were used. Liver and blood samples were collected every 10 days, from calving to 40 days postpartum, for gene expression and for -hydroxybutyrate and IGF-I assays, respectively. Samples for progesterone assay were collected every other day, from day 10 to 40ápostpartum. Three cows ovulated before 40ádays postpartum. IGF-I concentration was higher in Angus x Nelore than in Angus cows. There was no difference in the expression of GHR, GHR 1A and IGF-I according to breed or ovulatory status. IGF-I concentrations were higher in crossbred cows, but have not changed according to postpartum ovulatory status. Moreover, changes in postpartum IGF-I concentrations are not associated with changes in liver GHR, GHR 1A and IGF-IámRNA expression in either breed.  aCattle  aOvulation  aZebu  aBos Indicus  aBos Taurus  aGHR  aIGF-I  aMRNA hepatic expression1 aPFEIFER, L. F. M.1 aHAX, L. T.1 aPALUDO, G. R.1 aDEL PINO, F. A. B.1 aDIONELLO, N. J. L.1 aCORREA, M. N.  tPesquisa Agropecuária Brasileira, Brasília, DFgv. 45, n. 8, p. 925-931, ago. 2010