[The GHRH test in Turner's syndrome]

GHRH test was performed in 11 girls suffering from Turner's syndrome ranging in age from 5.6-13.5 years. GH peak resulted lower than 10 ng/ml in three subjects, who had also shown reduced GH values after two conventional pharmacological stimuli (L-dopa- and insulin-induced hypoglycemia) and a value of mean GH concentration over 24 hours lower than 3 ng/ml. Both GH peak and area under the curve were not correlated with height, height velocity, bone age/chronological age ratio, GH peak after conventional pharmacological stimuli and mean GH value of spontaneous secretion. The comparison with the results of GHRH test in other kinds of short stature evidenced in girls with Turner's syndrome the presence of GH values (peak and area under the curve) higher than those in subjects with "classical" GH deficiency, lower than those in "short normal stature" and similar to those in subjects with "non classical" GH deficiency. In conclusion, our data suggest, even if within a certain variability of the responses, a possible involvement of GH deficiency to the pathogenesis of short stature in Turner's syndrome, suggesting the existence of a prevalent hypothalamic nature of GH deficiency.