Hyperglycemic hormones are released at what plasma glucose level?

• A. 65-70 mg/dL
• B. 80-85 mg/dL
• C. 40-45 mg/dL
• D. 100-110 mg/dL

Answer: (A)

Hyperglycemic hormones are released when blood glucose starts to fall toward the lower end of the normal range in order to raise glucose back up. The first responders are glucagon from pancreatic alpha cells and epinephrine from the adrenal medulla; they act quickly to increase hepatic glucose production through glycogenolysis and gluconeogenesis and to limit glucose uptake in tissues. If glucose remains low for a longer period, growth hormone and cortisol come into play to sustain glucose production over hours by promoting gluconeogenesis and lipolysis. So the onset of these counter-regulatory hormones occurs at the lower end of the normal glucose range, which is why that threshold best fits the idea of hyperglycemic hormones being released to defend against falling glucose.