Deterioration of growth hormone (GH) response and anterior pituitary function in young adults with childhood-onset GH deficiency and ectopic posterior pituitary: a two-year prospective follow-up study.

Context: The current criteria for definition of partial GHD in young adults are still a subject of debate. Objectives: The objective of the study was to reinvestigate anterior pituitary function in young adults with congenital childhood-onset GHD associated with structural hypothalamic-pituitary abnormalities and normal GH response at the time of first reassessment of GH secretion. Design and Setting: This was a prospective explorative study conducted in a university research hospital. Patients and Methods: Thirteen subjects with a mean age of 17.2 0.7 yr and a peak GH after insulin tolerance test (ITT) higher than 5 g/liter were recruited from a cohort of 42 patients with childhoodonset GHD and ectopic posterior pituitary at magnetic resonance imaging. GH secretion after ITT and GHRH plus arginine, IGF-I concentration, and body mass index, waist circumference, blood pressure, total cholesterol, and fibrinogen were evaluated at baseline and at 2-yr follow-up. Results: At mean age of 19.2 0.7 yr, the mean peak GH response decreased significantly after ITT (P 0.00001) and GHRH plus arginine (P 0.0001). GH peak values after ITT and GHRH plus arginine were less than 5 and 9 g/liter in 10 and eight patients, respectively. Additional pituitary defects were documented in eight patients. Significant changes were found in the values of IGF-I SD score (P 0.0026), waist circumference (P 0.00001), serum total cholesterol (P 0.00001), and serum fibrinogen (P 0.0004). Conclusions: The results of this study underline the importance of further reassessment of pituitary function in young adults with GHD of childhood-onset and poststimulation GH responses suggestive of partial GHD. (J Clin Endocrinol Metab 92: 3875–3884, 2007)