“…It has been shown that a considerable propor tion of adults and children with GH defi ciency show an increase of plasma GH in response to an intravenous GRF bolus, which has been interpreted as an indication that in these cases the GH deficiency is of hypothalamic origin [3][4][5][6][7][8], On the other hand, a negative GH response to GRF does not exclude a hypothalamic origin, as prim ing the pituitary with repeated GRF boluses can increase the GH response [9], Theoretically, GRF could be used as a therapeutical agent in GH deficiency of hy pothalamic origin. This was confirmed for GRF administered every 3 h by intravenous and subcutaneous infusion [10,11], Later, GH-deficient children were treated with one or two subcutaneous injections daily by var ious investigators, but the results were quite variable [12][13][14][15], At present, it has not been firmly established which dosage and which frequency of administration leads to results which are as good as these of GH therapy. In addition, not all GH-deficient children re spond favourably, even when only those children are selected who show a clear GH response to the diagnostic intravenous GRF test.…”