Levels of tyrosine phosphorylation for IR, IGF-1R, IRS-1 and IRS-2 in bovine adipose tissue at one week post partum (1 WPP) and 5 months of gestation (5 MG).

Western blots showing the tyrosine phosphorylation levels of IRβ (A), IGF-1Rβ (B), IRS-1 (C) and IRS-2 (D) in adipose tissue lysates from dairy cows at one week post partum (1 WPP, n = 8 animals) and 5 of months gestation (5 MG, n = 8 animals). Immunoprecipitation (IP) was performed before gel electrophoresis. The antibody used is indicated as follows: IP: molecule X; the immune sera used to determine protein phosphorylation levels are indicated to the left of the gels (e.g., PY20 is directed against anti-phosphotyrosine residues). The levels of phosphorylation of IR, IGF-1R, IRS1 and IRS-2 were normalized with respect to the corresponding total protein, with specific antibodies, as indicated to the left of the gels. The gels show protein bands, which are underlined for each group, with four dairy cows per group. From left to the right, the groups are 1 WPP and 5 MG. Below each gel, the histograms show the mean ± SEM for a total of n = 8/group. *indicates a significant difference (p<0.05).