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.

Acromegalic features in growth hormone (GH)-deficient patients after long-term GH therapy.

BACKGROUND: Craniofacial, hand, foot and somatic growth depend on normal GH secretion. Acromegalic features have been described in children with GH insensitivity after IGF-I treatment. We observed patients with acromegalic features such as increase of foot size, nose and jaw enlargement among our cases with GH deficiency, treated with standard recombinant (rh)GH doses. The aim of our study was to analyse the possible factors involved in the development of acromegalic features in these patients. PATIENTS: We evaluated 21 patients, 17 with combined pituitary hormone deficiency and four with isolated GH deficiency treated with rhGH (0.05-0.15 U/kg/day, sc, at night) for 2-12 years who achieved final height. IGF-I and IGFBP-3 were measured before and every 6 months during therapy and bone age was evaluated yearly. At the end of therapy, patients' hand and foot sizes and height were measured and plotted on nomograms for hand according to height and age, and foot size according to height. Lateral radiographs of the face were performed to obtain the linear measurement of the lower jaw length. RESULTS: Foot size was greater than 97th percentile in 8/21 patients and lower jaw length was greater than +2SD in 4/21 patients. Patients were classified in two groups: group 1 (with foot size greater than 97th percentile and/or lower jaw length greater than +2SD) consisted of 11 patients (six females); nine had combined pituitary hormone deficiency (six associated to hypogonadotrophic hypogonadism) and three had isolated GH deficiency; group 2 (with foot size smaller than 97th percentile and lower jaw length less than +2SD) consisted of 10 patients (seven boys); nine had combined pituitary hormone deficiency (six associated to hypogonadotrophic hypogonadism) and one with isolated GH deficiency. During treatment, IGF-I levels ranged from < or = 3 to +2SD and IGFBP-3 levels ranged from -3 to +2SD, in both groups. We observed no statistically significant differences between the two groups regarding chronological age, bone age, height at the beginning and at the end of therapy, pubertal development, duration of rhGH treatment and IGF-I and IGFBP-3 levels (P > 0.05). Foot size percentile exceeded final height percentile in 11/21 patients (seven girls). CONCLUSION: Long-term rhGH treatment with standard doses might be associated with acromegalic features (increased foot size and lower jaw measurements) in patients with GH deficiency who achieved final height, especially in girls. Neither the clinical nor the hormonal parameters, IGF-I and IGFBP-3 levels, were useful to predict the development of these features. Further studies are necessary to analyse the frequency of this side-effect and how to prevent it.

Pituitary magnetic resonance imaging and function in patients with growth hormone deficiency with and without mutations in GHRH-R, GH-1, or PROP-1 genes.

Pituitary stalk interruption and ectopic posterior lobe on magnetic resonance imaging (MRI) are frequently observed in patients with GH deficiency (GHD), but their pathogenesis remains controversial. We performed pituitary stimulation tests, MRI, and studied GH-1, GHRH receptor (GHRH-R), and Prophet of Pit-1 (PROP-1) genes in 76 patients with GHD. Of 33 patients with isolated GHD, 4 had GH-1 deletions and 4 had GHRH-R mutations; of 43 patients with combined pituitary hormone deficiency, 1 had PIT-1 and 5 had PROP-1 mutations. Compared with the 62 patients without mutations, 14 patients with mutations had higher frequency of consanguinity (57 vs. 2%, P < 0.001), familial cases (21 vs. 3%, P < 0.05), and lower frequency of breech delivery or hypoxemia at birth (0 vs. 39%, P < 0.005). On MRI, all patients with mutations had an intact stalk, whereas it was interrupted or thin in 74% without mutations (P < 0.001). The posterior pituitary lobe was in normal position in 92% of patients with mutations against 13% without mutations (P < 0.001). Among patients with combined pituitary hormone deficiency, hormonal deficiencies were of pituitary origin in all with PROP-1 and PIT-1 mutations and suggestive of hypothalamic origin in 81% without mutations. Perinatal insults were associated with thin/interrupted pituitary stalk, ectopic posterior lobe, and hypothalamic origin of hormonal deficiencies. In contrast, GH-1, GHRH-R, and PROP-1 mutations were associated with consanguineous parents, intact pituitary stalk, normal posterior lobe, and pituitary origin of hormonal deficiencies. We conclude that pituitary MRI and hormonal response to stimulation tests are useful in selection of patients and candidate genes to elucidate the etiological diagnosis of GHD.

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.