Provocative tests for growth hormone release

Subnormal growth hormone responses to both insulin-induced hypoglycemia and arginine infusion (peak response less than or equal to 5 ng/ml) were found in five male subjects (aged 10 to 14 years) with short stature but with normal interval growth rates and normal bone ages (in 4 cases). They demonstrated one or more normal GH responses to subsequent provocation by glucagon stimulation, tolbutamide-induced hypoglycemia, and repeat insulin and arginine testing following pretreatment with sex steroids. Two subjects had received exogensou GH therapy for six months prior to the subsequent assessment; each one failed to demonstrate the growth response characteristic of GH deficiency. These studies indicate the need for multiple provocative human GH testing to exclude children whose growth would not be enhanced by GH therapy despite a subnormal response to provocative tests with insulin and arginine.