IS THE PERSISTENCE OF ISOLATED GH DEFICIENCY IN ADULTHOOD PREDICTED BY ANATOMICAL HYPOTHALAMIC-PITUITARY ALTERATIONS

The aim of this study was to verify the persistence in adulthood of GH deficiency diagnosed in childhood and treated with hGH in childhood a nd to study whether anatomical hypothalamic-pituitary alterations eval uated by magnetic resonance (MR) imaging could predict it. To this goa l, in six GHD adults (3 males and 3 females aged 17.2-24.5 yr, BMI 21. 8+/-1.3), we studied anterior pituitary hormone response to GHRH (1 mu g/kg iv)+pyridostigmine (120 mg po) + GnRH (100 mu g iv) + TRH (400 m u g iv) + hCRH (100 mu g iv) as well as brain MR imaging. In childhood , the diagnosis of severe isolated GHD had been done based on auxologi cal findings as well as on GH response <7 mu g/L after two classical p rovocative stimuli. In the present study, hormonal responses showed th e persistence of severe isolated GHD in 4 out of 6 patients (peak, mea n+/-SEM: 3.8+/-0.6, range 2.6-4.8 mu g/L). In these patients, IGF-I le vels were found low or low-normal. In other 2 patients, a clear GH res ponse to stimulation ( peak: 51.3 and 43.0 mu g/L, respectively) toget her with normal IGF-I levels were found. No other anterior pituitary h ormone deficiency was present in all subjects. MR imaging showed pitui tary hypoplasia in all patients with persistent GHD; in 2 out of them, pituitary stalk interruption and ectopic neurohypophysis was also pre sent. On the other hand, MR imaging showed normal hypothalamo-pituitar y morphology in the 2 subjects with normal somatotrope response. In co nclusion, our present data indicate that testing with a potent stimulu s such as GHRH+pyridostigmine is a reliable method to assess the persi stence of GH deficiency which associates with anatomical hypothalamic- pituitary alterations at the MR imaging. Patients with transient GH de ficiency in childhood and normal pituitary GH reserve in adulthood hav e normal hypothalamic-pituitary MR imaging. (C) 1997, Editrice Kurtis.