Reduced spontaneous growth hormone secretion in patients with Turner's syndrome

We evaluated growth hormone (GH) secretion in 81 patients with Turner's syn drome (TS) (mean age 10.7 +/- 3.6 y) with respect to karyotype, auxological characteristics and growth response to GH treatment (1 IU/kg/wk). None of the patients had spontaneous puberty or had started replacement therapy wit h estrogens. Thirty-nine patients (48%) had monosomia 45X, 29 (36%) structu ral abnormalities of the X chromosome and 13 (16%) X mosaicism. Before the start of GH therapy, each patient underwent an evaluation of mean nocturnal GH concentration (MGHC) and 75 patients also underwent 2 pharmacological t ests. MGHC of the TS patients did not differ from that of 29 prepubertal GH -deficient girls (GH peaks < 8 mu g/l after pharmacological tests) and both groups were lower (p < 0.0001 and p < 0.0005, respectively) than MGHCs of 27 short normal girls (GH peak > 8 mu g/l). MGHC of the patients with TS wa s negatively correlated (p < 0.001) with bodyweight excess (BWE) at multipl e regression analysis. MGHC of the TS patients with BWE < 20% was significa ntly higher (p < 0.02) than that of the TS patients with BWE > 20%, but aga in did not differ from that of the GH-deficient patients and was lower (p < 0.001) than that of the short normal girls. MGHC did not significantly dif fer between the 3 groups subdivided according to karyotype. Forty-few perce nt of the TS patients showed GH responses to pharmacological tests < 8 mu g /l. Height velocity SDS at first and second year of therapy was not influen ced by MGHC levels, chronological or bone age, target height or BWE. In con clusion, spontaneous secretion in our patients with TS was lower than that of the short normal prepubertal girls and did not differ from that of GH-de ficient subjects, even if we excluded overweight patients. The level of GH secretion was unable to predict GH response to treatment.