Investigation of GH Insufficiency	

	Methods of testing the hypothalamopituitary axis are legion (Fig. 14.20), and the interpretation of results of GH tests requires consideration of the circumstances, particularly in the patient with delayed puberty whose GH response can be amplified by the administration of testosterone (to a boy), 100mg, given intramuscularly three days before the test, or of ethinyloestradiol 30µg (to a girl) for three days. When investigations are required to investigate a low growth velocity, these should comprise testing of the whole hypothalamopituitary axis and should be undertaken in a centre that is properly staffed and equipped for the safe investigation of children with endocrine problems .