Glucagon propranolol test

Purpose

To investigate somatotropic function in growth retardation by using an associated assay to stimulate growth hormone secretion. This test associates the effect of Gucagon on the alpha-adrenergic receptors, involved in GH-RH secretion, and beta blocking agents’ inhibitor effect on the somatostatine secretion, consequence of a higher response in hCG. This is a front line test among the most efficient.

Subject preparation

• Fasting for 12 hours. Children can eat before the beginning of the challenge
• Away from any stimulation at least 2 hours prior the beginning of the challenge

Product

• Glucagon Novo® , Novo Nordisk Pharmaceutical SA (1mg bottle)
• Propranolol, Avlocardyl®, Astra Zeneca (40 mg tablet or 5mg/5ml vial – oral administration)

Dose

• Glucagon (Glucagon Novo®) : 1 mg or 0.5mg if child is less than 1 year old, by slow IV injection.
• Propranolol (Avlocardyl®): 0.75 mg /kg body weight without exceeding 40 mg, oral administration.

Protocol

• Commence the perfusion of normal saline 30 minutes before the challenge.
• Blood samples (1 dry tube and 1 fluoride tube) at T-30 min.
• Oral administration of the correct dose of propranolol.
• Blood samples (1 dry tube and 1 fluoride tube) at T0.
• IM injection of 1 mg glucagon.
• Blood samples (1 dry tube and 1 fluoride for each time interval) at the time intervals: T+30, T+60, T+90, T+120, T+150 and T+180 min.

Samples

After centrifugation, draw off the serum and plasma. Freeze the serum and store plasma at +4°C.

Side effects

Close medical supervision (with regular measurements of pulse and blood pressure) due to the risk of:

• Bradycardia and faintness due to the propranolol.
• Vomiting and hypoglycaemia at the end of the glucagon challenge.

Contraindications

• Asthma.
• Heart failure.