GH values after clonidine stimulation measured by immunofluorometric assay in normal prepubertal children and GH-deficient patients.

OBJECTIVE: To establish the cut-off values of GH measured by immunofluorometric assay, a more sensitive and specific assay, in normal prepubertal children and compare their values with those of proven GH-deficient patients. METHODS: 30 normal children (20 males) and 26 patients with known causes of GH deficiency were submitted to the clonidine test and their GH values were compared. A powdered clonidine tablet (0.1 mg/m(2)) was given orally and blood samples for GH measurements were drawn at times -30, 0, 60, 90 and 120 min. RESULTS: GH peak values presented a wide variation ranging from 1.7 to 25 micro g/l (mean +/- SD = 12.87 +/- 5.8 micro g/l) in the normal group. The cut-off values for the 5th and 10th percentiles of the distribution curve were 3.3 and 5.5 micro g/l, respectively. In the GH deficiency group, maximum GH levels after clonidine stimulation ranged from <0.1 to 2.1 micro g/l (0.56 +/- 0.58 micro g/l). CONCLUSIONS: The cut-off values obtained with the immunofluorometric method are lower than the ones obtained by radioimmunoassay. We suggest a cut-off value of 3.3 micro g/l (5th percentile) that ensures 100% of sensitivity along with 93% of specificity to exclude the diagnosis of GH deficiency when using this immunofluorometric method.

Telarca reversível espontaneamente em meninas pré-púberes durante o tratamento com hormônio de crescimento recombinante humano / Reversible thelarche spontaneously in pre-puberal girls during of the treatment with human recombinant growth hormone

OBJETIVO: Descriçäo de 4 casos de desenvolvimento transitório de mamas em meninas pré-púberes tratadas com hormônio de crescimento recombinante humano (rhGH). CASUíSTICA E MÉTODOS: Quatro meninas pré-púberes com baixa estatura, duas com síndrome de Turner (ST) e duas com deficiência de hormônio de crescimento (DGH). O desenvolvimento das mamas (Tanner II e III) ocorreu com idade cronológica (IC) de 5,6 e 7,7 anos e idade óssea (10) de 5,7 a 6,9 anos, 2 a 60 meses após o inicio do tratamento com rhGH na dose de 0,1 - 0,15U/kg/d. Todas as pacientes apresentaram regressäo espontânea da telarca num período de 8 a 15 meses. Três pacientes foram submetidas ao teste de estímulo com GnRH apresentando resposta pré-puberal de LH. DISCUSSäO: O desenvolvimento de mamas após o início do tratamento com rhGH tem sido relatado em meninos, mas näo em meninas pré-púberes. Concluímos que o rhGH pode induzir ao desenvolvimento transitório das mamas, também em meninas, sem a ativaçäo do eixo hipotálamo-hipófise-gonadal, näo se fazendo necessária a supressäo da puberdade.

Body composition and bone mass of children with hypopituitarism following six months of human growth hormone therapy

Total body composition and the bone mineral content (BMC) and density (BMD) of 8 perpubertal (4 boys and 4 girls) GH-deficient children aged 6-14 years were investigated before and during a 3-6 month period on human growth hormone (hGH) therapy (0.075 IU/Kg/day, sc.); measurements were made by dual energy x-ray absorptiometry (DEXA). Before hGH therapy, total body fat mass was 4 + 3 kg and the total body percentage of fat was 22 + 12 per cent; the total lean mass was 14 + 3 kg. Total BMC was 625 + 163 g, and total BMD was 0.777 + 0.025 g/cm2. When compared with a matched population of normal children, GH-deficient children presented decreased lean mass (-0.9 to -5.9 SD), BMC (-0.9 to - 5.6 SD) and BMD (-0.1 to -4 SD). Fat mass, as a percentage, was not significantly different between populations (22 + 12 per cent in GH-deficient children vs. 17 + 5 per cent in normal children, p>0.05). Therapy with hGH was associated with: (I) a major decrease of total body percentage of fat mass: -31 + 15 per cent after 6 months (p<0.05); and with (II) an increase in the total lean mass and total BMC, 14 + 8 per cent and 7 + 5 per cent, respectively (both p<0.05). Total BMD was not significantly changed after 6 months of hGH therapy. We conclude that hGH replacement therapy results in a major and rapid decrease of total fat mass and in a less pronoucend increase of total lean mass.