GROWTH-RESPONSE AND LEVELS OF GROWTH-FACTORS AFTER 2 YEARS GROWTH-HORMONE TREATMENT ARE SIMILAR FOR A ONCE AND TWICE-DAILY INJECTION REGIMEN IN GIRLS WITH TURNER-SYNDROME

GH is known to improve height velocity in girls with Turner syndrome ( TS) but the optimal dosage regimen has yet to be defined. OBJECTIVE We attempted to improve the growth response by trying to mimic normal pu lsatile GH secretion more closely. DESIGN In a 2-year study the effect of fractionated twice daily (BID) was compared with once daily (OD) s .c. injections of a total GH dose of 6 IU/m(2)/day. BID injections wer e administered as two-thirds at bedtime and one-third in the morning. The subjects concurrently received low dose ethinyl oestradiol (0.05 m g/kg/day, orally). SUBJECTS Nineteen girls with TS aged 11 years or ov er, who were previously involved in a 18-week GH cross-over study. MEA SUREMENTS Height and bone age were evaluated in relation to untreated Turner reference data. Final height (FH) was predicted using the Bayle y and Pinneau (BP) method, the modified Index of Potential Height (mIP H(RUS)), and a recently developed Turner-specific method (PTSRUS) base d on regression coefficients for height (H), chronological age (CA) an d bone age (BA). Plasma levers of GH, GHBP, IGF-I, and IGFBP-3 were de termined by RIA. RESULTS After 2 years treatment the growth response e xpressed as HV, HVSDS, the change in HSDSCA, the gain in height over e stimated untreated Values and in FH prediction all showed significant improvements. Although mean values tended to be higher with OD injecti ons, significant differences between groups were not found. Bone matur ation was similar between groups and compared with untreated estimated values. Independent of treatment group, the change in HSDSCA after 2 years of GH treatment was related negatively to the baseline CA and HS DSCA, and positively to BA delay at baseline. After 18 months of GH tr eatment the significant decrease in GHBP plasma levers observed after 6 months was no longer significant. In contrast, IGF-I and IGFBP-3 pla sma levels and the IGF-I to IGFBP-3 ratio increased significantly duri ng 18 months GH therapy. None of these growth related factors showed a difference between groups in their 18 months change. Relevant side-ef fects were not observed during the first 2 years of GH treatment. CONC LUSIONS The present growth data are in conformity with the data of the earlier 24-hour GH profiles. The growth response and plasma revels of growth related factors after 2 years GH an a total dose of 6 IU/m(2)/ day in combination with low-dose oestrogens were not significantly dif ferent between the once daily and the twice daily GH injection regimen .