RESUMO
OBJECTIVES: Patients with single allele defects in the gene encoding the type 1 IGF receptor have been reported to have growth failure, but fibroblasts from affected patients have not exhibited insensitivity to the effects of IGF-I in vitro. The in vitro and in vivo responses to short-term recombinant human IGF-I (rhIGF-I) in a severely growth-retarded girl with ring chromosome 15 and deletion of a single allele for the type 1 IGF receptor gene have been investigated. DESIGN AND PATIENT: The child exhibited prenatal and severe post-natal growth failure, and delayed psychomotor development. Southern blotting revealed a 50% reduction in IGF-I receptor DNA, and in an RNase protection assay (RPA), a quantitatively similar reduction in steady-state mRNA for type 1 IGF receptor. rhIGF-I was administered in graded doses of 40, 60 and 80 microg/kg twice daily by subcutaneous injection for periods of 2-2.5 days each. RESULTS: During rhIGF-I treatment, mean urinary nitrogen excretion was unchanged and urinary calcium rose to 60% greater than in the pre-treatment period. rhIGF-I injections produced only a modest decrease in indices of GH secretion, assessed by frequent (every 20 min) sampling over periods of 12 h. There was no significant difference between the mean GH concentrations during rhIGF-I treatment (5.32 +/- 6.2 mU/l) compared with that before rhIGF-I treatment (8.46 +/- 10.2 mU/l). Mean IGFBP-3-values were increased (4.5 mg/l before vs. 5.4 mg/l during rhIGF-I). TSH values after injection of TRH were not significantly reduced by IGF-I (mean of all values, 18.6 mU/l vs. 15.5 mU/l during rhIGF-I treatment). In vitro binding of radiolabelled IGF-I to the patient's fibroblasts was less than that bound by control fibroblasts (patient, 0.69% binding by 248 000 cells, vs. 1.41% binding by 260 000 fibroblasts from an age-matched control). However, the patient's fibroblasts exhibited a growth response in vitro to the addition of IGF-I in a fashion similar to that of control fibroblasts. CONCLUSIONS: These studies show evidence in each of the indices examined of in vivo resistance to IGF-I and suggest that the growth retardation observed in such patients may be the direct result of the absence of one of the alleles encoding the type 1 IGF receptor.
Assuntos
Cromossomos Humanos Par 15 , Deleção de Genes , Transtornos do Crescimento/genética , Fator de Crescimento Insulin-Like I/uso terapêutico , Receptor IGF Tipo 1/genética , Cromossomos em Anel , Southern Blotting , Células Cultivadas , Pré-Escolar , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Transtornos do Crescimento/tratamento farmacológico , Transtornos do Crescimento/metabolismo , Hormônio do Crescimento/sangue , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , RNA Mensageiro/análise , Receptor IGF Tipo 1/metabolismo , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/uso terapêuticoRESUMO
We report 13 cases of benign intracranial hypertension (IH) in children with growth hormone (GH) deficiency treated with GH in the United States. The group consisted of eight boys and five girls, 3 to 16 years of age (median, 9 years). The interval from starting GH therapy to diagnosis of IH was 2 weeks or less in six patients, between 2 and 12 weeks in four, 8 months in one, 5 years in one, and unknown in one. Seven patients were not known to have previously described IH risk factors; the other six had at least one factor each. All patients but one had headache, nausea, vomiting, and visual changes. All had papilledema, and cerebrospinal fluid pressures were elevated (> 250 mm H2O) in all nine patients tested. The GH dosage range was 0.17 to 0.35 mg per kilogram body weight per week (median, 0.30 mg/kg per week) for the 11 patients with dosage data. After discontinuation of GH and treatment with lumbar punctures and/or medications, signs and symptoms resolved in eight children; in two of these children signs and symptoms reappeared when GH therapy was restarted. In four patients signs and symptoms resolved while GH therapy was continued; one child was treated with a ventriculoperitoneal shunt because of an arachnoid cyst, after which GH was restarted without subsequent IH. In the 12 patients with idiopathic GH deficiency the course of IH was benign, with complete resolution of all signs and symptoms. Because doses and scheduling of GH administration have changed since the introduction of recombinant GH, higher doses and increased frequency of administration may be contributing to the development of IH in some patients. We suggest beginning therapy at the lowest recommended dose, with gradual titration to higher doses, and the performance of routine funduscopic examinations during initiation of GH therapy and whenever signs or symptoms of IH develop.
Assuntos
Hormônio do Crescimento/efeitos adversos , Hormônio do Crescimento/deficiência , Pseudotumor Cerebral/induzido quimicamente , Adolescente , Criança , Pré-Escolar , Esquema de Medicação , Feminino , Hormônio do Crescimento/administração & dosagem , Humanos , MasculinoRESUMO
We report 22 cases of prepubertal gynecomastia diagnosed during growth hormone (GH) treatment. The age and dose range were 2 to 12 years and 0.18 [corrected] to 0.3 mg/kg per week, respectively. In most of the patients, gynecomastia appeared between 0.5 and 7 months after GH was started. Three boys were using drugs other than GH. This condition appears to be self-limited and benign.
Assuntos
Hormônio do Crescimento/efeitos adversos , Ginecomastia/induzido quimicamente , Criança , Pré-Escolar , Hormônio do Crescimento/uso terapêutico , Humanos , MasculinoRESUMO
Because some patients with growth hormone (GH) deficiency are found to be hypothyroid after initiation of treatment with GH, we assessed the predictive value of the nocturnal thyrotropin surge (a sensitive test for central hypothyroidism) in 56 untreated GH-deficient children and adolescents. Eighteen patients had a subnormal thyrotropin surge (mean 18% (range -30% to 46%)), significantly less than that of 96 normal control subjects (mean 124%; 95% confidence limits, 47% to 300%; p less than 0.01); 13 of the 18 had a subnormal total thyroxine (T4) level or a subnormal free T4 level, or both. These 18 patients were given thyroid hormone replacement therapy; GH deficiency was confirmed during treatment with thyroxine. Of the remaining 38 patients, who had no initial evidence of dysfunction of the hypothalamic-pituitary-thyroid axis, 23 were re-examined while they were receiving GH treatment. Hypothyroidism developed in none of those 23 children during GH therapy. The nocturnal thyrotropin surge test and determination of iodothyronine levels were repeated in 14 of these euthyroid patients. There was no significant change in mean thyrotropin surge (129% (range +49% to +300) vs 125% (range +51% to +222%)), mean serum level of total T4 (111 +/- 4 vs 103 +/- 3 nmol/L), mean serum level of free T4 (19 +/- 0.7 vs 18 +/- 0.8 pmol/L), mean serum level of triiodothyronine (2.5 +/- 0.1 vs 2.5 +/- 0.1 nmol/L), or mean serum level of thyrotropin (2.9 +/- 0.3 vs 2.9 +/- 0.5 mU/L (mean +/- SEM)). We conclude that GH treatment does not appreciably alter thyroid function in GH-deficient patients who have no evidence of thyroid axis dysfunction before GH treatment.