45 SmC RESPONSE TO hGH AND GH-RF IN GH-RF-DEFICIENT CHILDREN

4 GH-RF deficient children (1 with isolated GH-deficiency, 2 with GH-TSH deficiencies, 1 with GH-TSH-ACTH-deficiencies) were administered s.c. hGH (after the previous hGH treatment had been discontinued 1 week before the study) at a dose of 0,1 UI/Kg, according to usual substitutive therapy, at times 0 and 48 h. After a further week without therapy the subjects were administered i.v. GH-RF at a dose of 3 μg/Kg at times 0,8,16,24,32,40,48,56,64 h. SmC blood samples were collected at time 0 and, after hGH and GH-RF administrations, at times 4,8,12,16,24,28,32,36,40,48,52,56,60,64,72 h. In all patients a significant GH-response (> 4 ng/ml) was attained after each GH-RF administration. In 3 subjects a SmC increase was observed after both hGH and GH-RF administrations. In 1 case there were no changes in SmC levels after both hGH and GH-RF administrations. By calculating the integrated areas of the SmC curve, the values obtained after hGH and GH-RF administrations were higher in 2 cases after the GH-RF injection, higher in 1 case after the hGH injection, and in 1 case the areas were similar. In our patients and in our experimental conditions we did not find differences in the SmC release between the usual hGH therapy and GH-RF administration.