ZAG inhibits insulin action <i>via</i> β1/β2-AR signaling.

<p>Differentiated SGBS adipocytes were pre-treated for 30 min with or without 1 μM propranolol prior to culture with 25 μg/ml ZAG for 24 hours. <b>(A)</b> Glucose uptake was measured after stimulation with 100 nM insulin (Ins) for 30 minutes by incorporation of labelled 2-deoxyglucose into the cells for the final 10 minutes of culture. Left panels represent mean±SEM of 3 independent experiments performed in triplicate and are expressed as pmol glc/mg prot/10 min. Right panels represent percentage of stimulation produced by insulin over control cells (no insulin, without or with ZAG respectively). *, P < 0.01. <b>(B)</b> GLUT1 and GLUT4 mRNA expression were analyzed by qPCR in adipocytes pre-treated with 1 μM propranolol or 300 nM CPG20712A (CPG) prior to culture with ZAG. Data are presented as mean±SEM (n = 3). *, P < 0.01 vs control. <b>(C)</b> Lysates from differentiated SGBS cells pre-treated with propranolol or CPG prior to culture with ZAG and 100 nM insulin (Ins) for 15 minutes were analyzed by western blotting using antibodies against phosphorylated and total Akt (Ser473). A representative experiment is shown together with densitometric analysis of phosphorylated <i>vs</i> total proteins (3 independent experiments). *, P < 0.01.