Whole-animal insulin sensitivity in CF and non-CF ferrets. A–E, Hyperinsulinemic euglycemic clamps in conscious CF and non-CF ferrets ranging from 70–307 days of age, depicting (A) blood glucose, (B) glucose infusion rate (GIR), (C) total insulin, and (D) GIR during the last 30 minutes of the clamp. E, Relationship between GIR and age. F, Mean cortisol levels at the indicated time range in clamped animals shown in A–E.