Skip to main content
. 1999 Aug 15;104(4):447–457. doi: 10.1172/JCI5971

Figure 3.

Figure 3

Protein levels, tyrosine phosphorylation of IRS-1 and IRS-2, and their association with P85 subunit of PI 3-kinase in the aorta ex vivo. (a) Protein levels of IRS-1 and IRS-2. Isolated aortas were homogenized, and equal amounts of protein (10 mg) were subjected to immunoprecipitation with αIRS-1 or αIRS-2 antibodies, separated by SDS-PAGE, and immunoblotted with the same antibody. Data (mean ± SD; n = 4) are expressed as relative to control, assigning a value of 100% to the lean control mean. *P < 0.05, lean vs. obese. (b and c) Insulin-stimulated tyrosine phosphorylation of IRS-1 and IRS-2. Isolated aortas were incubated without or with insulin (100 nM) in DMEM (0.1% BSA) for 30 minutes at 37°C. Equal amounts of protein (6 mg) were subjected to immunoprecipitation with αIRS-1 or αIRS-2 antibodies, separated by SDS-PAGE, and immunoblotted with αPY antibodies. (d and e) Association of p85 subunit of PI 3-kinase to IRS-1 and IRS-2. The same membranes used for the IRS tyrosine phosphorylation study were stripped and reblotted with αp85 subunit antibody (top panels). Data (mean ± SD; n = 4) in b–e are expressed as relative to control, assigning a value of 100% to the lean insulin mean. *P < 0.05, **P < 0.01, insulin lean vs. insulin obese.