Figure 4.

Effect of β-adrenergic blockade or β-adrenergic blockade plus insulin oscillation removal on the FFA oscillation. The top row shows the basal FFA profiles. The bottom row shows the effect of propranolol infusion (Prop. Inf.) or propranolol infusion plus insulin clamp (Prop. + Ins. Inf.) on the FFA profile. The left half shows two dogs in which propranolol or propranolol plus insulin clamp seemed to remove the FFA oscillation, as determined by ULTRA (see the text). The right half shows two dogs in which propranolol or propranolol plus insulin clamp significantly disrupted the FFA oscillation, but did not remove it.