An audit of 500 subcutaneous glucagon stimulation tests to assess growth hormone and ACTH secretion in patients with hypothalamic-pituitary disease

OBJECTIVE The insulin tolerance test (ITT) is usually regarded as the 'gold standard' for the assessment of the hypothalamic-pituitary axis (growth ho rmone (GH) and ACTH) but must be used with caution and is contra-indicated in certain groups of patients. The glucagon stimulation test (GST) has prev iously been shown to be a good alternative when the ITT is contra-indicated and like the ITT stimulates both GH and ACTH secretion. There is however l imited data on the use of the GST in patients with ehypothalamic-pituitary disease. DESIGN AND PATIENTS An audit of 500 GST was performed in 374 patients with hypothalamic-pituitary disease. Glucagon was administered via the subcutane ous route and bloods were taken at times 0 90 120 150 180 210 and 240 minut es. RESULTS In the vast majority peak GH (84.4%) and cortisol (93%) responses o ccurred between 120 and 180 minutes Little information was obtained from th e 240 minute sample. The medical supervision required was minimal and the s ide-effects encountered during this test were mild; 20% of the tests were a ssociated with nausea occasionally with vomiting sweating or headaches. Fou r patients fainted but recovered quickly. CONCLUSIONS This large audit has shown that the glucose stimulation test is well tolerated and can easily be performed in an out-patient setting with minimal medical supervision. The 240 minute sample added little additional information and could be omitted.