FIG. 5.
Inhibition of glucose uptake in rat adipocytes with z-His-Phe-Phe-Bpa-[125I]Tyr-O-Et. A, the indicated concentrations of peptide were added to insulin-stimulated primary rat adipocytes 1 min prior to measuring [3H]2-deoxyglucose uptake (1 min at 37 °C). HFF and CB represent positive controls in which 200 μM of the peptide zHFFe or 20 μM cytochalasin b, respectively, were added to the assay mixture. B, insulin-stimulated primary rat adipocytes were treated with the indicated concentrations of peptide and exposed to 254 nm light (black bars) or kept in the dark (gray bars) for 3 min at 37 °C. The adipocytes were then immediately washed three times with KRB to remove unreacted peptide before measuring residual 2-deoxyglucose transport activity. All assays were performed in triplicate and the values shown represent the mean ± S.E. Asterisks (*) indicate p < 0.05 compared with untreated control as determined by the Student's t test.