Responses to GHRH plus arginine test are more concordant with IGF-I circulating levels than responses to arginine and clonidine provocative tests.

BACKGROUND/OBJECTIVE: Although pharmacological GH stimulation tests are still considered the gold standard for GH deficiency (GHD) diagnosis, they are burdened by poor specificity. The majority of children diagnosed as having GHD show normal GH responses when re-tested at the end of growth, thus questioning the initial diagnosis. We evaluated the concordance between IGF-I levels and GH responses to provocative tests. METHODS: We analyzed 105 GHRH plus arginine tests, 79 arginine tests, and 124 clonidine tests performed in 192 short children. IGF-I levels ≤-2SD score (SDS) were considered suggestive for high likelihood of GHD. The percentage of positive and negative results for each test was determined and compared with IGF-I levels, clinical follow-up and response to therapy. RESULTS: In children with IGF-I>-2SDS the arginine test showed a concordance rate of 6.9%, the clonidine test of 28.6%, and GHRH plus arginine test of 70%. In children with IGF-I≤-2SDS the concordance was 96.1%, 85.7%, and 46.4%, respectively. The overall concordance was 66.7% for GHRH plus arginine, 42.7% for clonidine, and 27.8% for arginine tests. CONCLUSION: Our results suggest that GHRH plus arginine test provides the best concordance with the assessment of IGF-I levels thus suggesting that the combination of the two procedures may significantly reduce the need of a second provocative test.

Catch-up growth in body mass index is associated neither with reduced insulin sensitivity nor with altered lipid profile in children born small for gestational age.

OBJECTIVE: Low birth weight is a risk factor for coronary heart disease. Persons who have coronary events as adults tend to have been small at birth and thin at 2 yr of age, after which they tended to increase their body mass index (BMI). Our aim was to determine whether BMI gain is associated to alterations in insulin sensitivity and/or lipid profile in children born small for gestational age (SGA). DESIGN: Retrospective case-control study. METHODS: We studied 78 children (mean age 7.8+/-2.5 yr): 26 SGA children with catch-up growth in BMI (CGB-SGA) (BMI= 10th to 75th centile), 26 SGA without catch-up growth (NCGB-SGA) (BMI<10th centile), and 26 appropriate for gestational age (AGA) control children (BMI: 10th to 75th centile). For each CGB-SGA child, we selected an NCGB-SGA and an AGA child of the same gender, age (within 1 yr), and pubertal status. SGA children were also subdivided into 2 groups according to post-natal catch-up growth in height (CGH). RESULTS: Glucose was significantly lower in NCGBSGA than AGA group (p=0.02). No significant differences in fasting insulin, fasting glucose/insulin ratio, homeostasis model assessment, quantitative insulin-sensitivity check index, and lipid profile were found among the 3 groups. HDL-cholesterol proved significantly reduced in SGA children with post-natal CGH (p=0.02). CONCLUSIONS: Our findings do not support the hypothesis of early alterations in insulin sensitivity and lipid metabolism in CGB-SGA subjects during childhood provided that BMI remains within the normal range. Finally, the finding of reduced HDL-cholesterol levels in CGH-SGA children suggests detrimental metabolic effects of the height gain.

Growth hormone therapy does not alter the insulin-like growth factor-I/insulin-like growth factor binding protein-3 molar ratio in growth hormone-deficient children.

BACKGROUND: Recent studies have linked raised levels of IGF-I and/or reduced levels of its main binding protein, IGF binding protein (IGFBP)-3, with the risk of developing cancer. A GH dose-dependent increase in IGF-I/IGFBP-3 molar ratio has been reported in subjects treated with GH, raising concern about the long-term safety. OBJECTIVE: The aim of this study was to evaluate changes in serum IGF-I, IGFBP-3, and IGF-I/IGFBP-3 molar ratio over the first 12 months of replacement GH therapy in GH deficient (GHD) children. METHODS: The study included 20 GHD children who had not previously received GH treatment, and 40 untreated non-GHD short children closely matched for age, gender, pubertal stage, and body mass index (BMI), as controls. Serum IGF-I, IGFBP-3 levels were measured before and after 12 months of GH treatment. Based on the molecular weight of IGF-I (7500) and IGFBP- 3 (40,000, mean of glycosylated variants), we calculated the molar ratio of IGF-I/IGFBP-3. RESULTS: IGF-I/IGFBP-3 molar ratio significantly increased during GH therapy (p=0.01). No significant difference in IGF-I/IGFBP-3 ratio was found between GHD children and controls at the different time points. In the multiple regression analysis, BMI (beta=0.33) and age (beta=0.33) proved to be the major predictors of the IGF-I/IGFBP-3 molar ratio (adjusted r2=0.53, p<0.0001). CONCLUSIONS: Our results suggest that at a conventional replacement dose GH does not alter the IGF-I/IGFBP-3 molar ratio. Potential fears related to long-term cancer risk are likely to be greatest in patients exposed to high-dose GH therapy and with genetic predisposition to high IGF-I and/or low IGFBP-3 concentrations.

Long-term treatment with growth hormone improves final height in a patient with Pallister-Hall syndrome.

Pallister-Hall syndrome is a disorder of development consisting of hypothalamic hamartoma, pituitary dysfunction, central polydactyly and visceral malformations. This disorder is inherited as an autosomal dominant trait and is caused by mutations of the GLI3 gene encoding a zinc finger transcription factor. We describe a case of Pallister-Hall syndrome with growth hormone neurosecretory dysfunction, successfully treated with growth hormone until attainment of final height. We conclude that children with Pallister-Hall syndrome and short stature be evaluated carefully for spontaneous somatotropic function and, if necessary, treated with growth hormone.

[Goiter prevalence and urinary excretion of iodine in a sample of school age children in the city of Rome]. / Prevalenza di gozzo ed escrezione urinaria di iodio in un campione di bambini in età scolare della città di Roma.

The aim of the study was the assessment of the urinary iodine excretion and the evaluation of thyroid volume compared with clinical examination in 1040 schoolchildren (6-14 years old), living in Rome. Mean urinary iodine excretion was 98.52 +/- 49.81 micrograms/l (median 92 micrograms/l). Thyroid enlargement, as assessed by palpation, was found to be grade 1A in 35.4% of the children, grade 1B in 9.6% and grade 2 in 0.2%. Thyroid volume, determined by ultrasound, increased with age, was significantly correlated with body surface area and was significantly higher in females, as compared to males, in the 11 and 12 years old group. Eleven children (1.9%) were negative at palpation (grade 0) but showed thyroid enlargement by ultrasound. The prevalence of goiter determined by ultrasound resulted to be 4.7%.

Urinary pyridinium collagen cross-links predict growth performance in children with idiopathic short stature and with growth hormone (GH) deficiency treated with GH. Skeletal metabolism during GH treatment.

GH is able to promote longitudinal growth in children with GH-deficiency (GHD) and in some children with idiopathic short stature (ISS). The objectives of this study were to evaluate the predictive value of bone and collagen markers on the growth response to GH therapy in children with ISS and with GHD, and to characterize the effects of GH treatment on bone and collagen turnover in children with ISS and with GHD. Twenty prepubertal short, slowly growing, children treated with GH, 15 IU/m2 per week, were studied; of them 13 (10 males) had ISS and 7 (5 males) had GHD. An overnight 12-h urinary collection and a fasting morning blood sample were obtained at baseline, 1, 3, 6, and 12 months of treatment. Urinary levels of collagen cross-links, pyridinoline (Pyd) and deoxypyridinoline (Dpd), and circulating levels of osteocalcin, intact PTH, calcitonin, procollagen type III aminoterminal propeptide (PIIINP), insulin-like growth factor-I, and alkaline phosphatase were determined. Urinary collection was also obtained from 127 healthy children (51 males) aged 6-13 yr. In children with ISS, the changes in Dpd over 1 month of GH therapy were related to the changes in height velocity (HV) over 1 yr of therapy (r = 0.67; P < 0.05); the changes in Pyd after 1 month of GH treatment were related to the changes in HV at 6 months of GH treatment (r = 0.57; P < 0.05). All the other markers evaluated were not related to the HV changes in children with ISS. In children with GHD, the changes in Pyd and in Dpd after 1 month of GH treatment were positively related to the changes in HV after 12 months of therapy (r = 0.82; P < 0.05, and r = 0.82; P < 0.05, respectively). The changes in Pyd after 1 month were also related to the HV changes after 6 months of GH (r = 0.77; P < 0.05). Positive relationships between the HV after 6 months of GH and the increases of PIIINP (r = 0.80; P < 0.05) and osteocalcin (r = 0.77; P < 0.05) after 3 months of GH therapy were observed. All patients showed urinary Dpd and Pyd excretions in the normal range. In patients with ISS, Pyd (P < 0.05), Dpd (P < 0.05), osteocalcin (P < 0.01), PIIINP (P < 0.01), and alkaline phosphatase (P < 0.01) increased longitudinally during the GH treatment and the increments reached a maximum after 3-6 months of therapy. Patients with GHD showed an increase of the same markers but the increases occurred earlier, after 1 month of GH therapy. The collagen cross-links, Pyd and Dpd, could be helpful early markers in predicting the responsiveness to GH therapy in children with ISS and with GHD. GH treatment stimulates bone and collagen metabolism.

Preliminary validation of a prediction model for the short-term growth response to growth hormone therapy in children with idiopathic short stature.

A discriminant scoring system, using multivariate analysis, has been developed for pretreatment prediction of responsiveness to a 6-month trial of growth hormone (GH) treatment in short children with subnormal growth velocity, but without GH deficiency. Inclusion criteria included a birth weight above 2.5 kg, height below the 3rd centile for chronological age, height velocity below the 25th centile for bone age, no signs of puberty, a maximal GH response to pharmacological stimulation of above 10 micrograms/l and treatment with GH at a dose of 12-16 IU/m2/week. Children with an increase in height velocity greater than 2.5 cm/year after therapy were considered to be responders. Pretreatment clinical data from 67 patients were employed in a discriminant analysis in order to establish the model. The scoring system developed was as follows: score = -0.4 + 0.92X1 - 0.87X2, where X1 is the height velocity SD score (SDS) for chronological age, and X2 is the bone age SDS for chronological age. This model had a specificity of 96.3% and a sensitivity of 92.5% in predicting the responsiveness to GH. The model has subsequently been applied to a group of 14 patients in order to establish its validity; in this group its sensitivity was 83.3% and its specificity 100%. These preliminary data suggest that the model can be used as a guideline for selecting short, slowly growing, non-GH-deficient children who will respond to short-term GH therapy.

Characterization of a low molecular mass form of insulin-like growth factor binding protein-3 (17.7 kilodaltons) in urine and serum from healthy children and growth hormone (GH)-deficient patients: relationship with GH therapy.

The insulin-like growth factor binding proteins (IGFBPs) are the carriers for insulin-like growth factor (IGF0-I and IGF-II. IGFBP-3 is GH-dependent and circulates associated with IGFs and an acid-labile subunit to form a 150-kilodalton (kDa) complex. In human serum, two immunoreactive molecular weight forms of IGFBP-3 have been identified. In human urine, radioimmunoassayable levels of IGFBP-3 have been detected. The objectives of this study were to characterize the molecular weight forms of IGFBP-3 in urine and serum of healthy children and adults and in children with GH deficiency (GHD), to quantify the urinary molecular weight forms of IGFBP-3, and to evaluate the relationship of these forms with GH therapy. Urine and serum were obtained from 12 prepubertal children with GHD, before and after 6 months of GH therapy, from 30 prepubertal healthy children, and from 8 healthy adults. Western immunoblotting (WIB) with IGFBP-3 antiserum (alpha IG-FBP-3g1) showed that in urine the most representative IGFBP-3 was a 17.7-kDa form. The 17.7-kDa IGFBP-3 was high in urine of healthy children compared with healthy adults and was low in children with GHD but increased after GH therapy. Urinary IGFBP-3 immunoreactive profile was determined by neutral-size exclusion chromatography, followed by IGFBP-3 RIA analysis of the fractions. Urine showed a major peak of IGFBP-3 immunoreactivity around 17 kDa. The 17-kDa urinary IGFBP-3 chromatographic peak averaged 8461 +/- 367 ng/12 h.m2 of body surface in healthy children, 3415 +/- 739 in adults (P < 0.001), 2294 +/- 354 in children with GHD before GH therapy (P < 0.001), and 7940 +/- 1874 in children with GHD after GH therapy. Urinary IGFBP-3 was also measured by RIA in unfractionated urine; healthy children showed levels significantly higher (14575 +/- 460 ng/12 h.m2) than adults (7823 +/- 1083, P < 0.001) and higher than children with GHD before GH therapy (4710 +/- 703, P < 0.001). Again, however, immunoreactive IGFBP-3 increased after GH treatment (12294 +/- 3394). In the serum of the healthy children we characterized by specific IGFBP-3 WIB analysis, a 17.7-kDa immunoreactive form of IGFBP-3 that was absent in the serum of healthy adults and low in patients with GHD, increased during GH therapy. Serum samples were subjected to neutral-size exclusion chromatography and the fractions were analyzed by WIB.(ABSTRACT TRUNCATED AT 400 WORDS)

Prediction of the outcome of growth hormone therapy in children with idiopathic short stature. A multivariate discriminant analysis.

OBJECTIVE: To identify, with the use of pretreatment clinical data, the children with idiopathic short stature responsive to treatment with growth hormone (GH). DESIGN: Open, prospective study in a university hospital. SUBJECTS: Patients admitted to the study met the following criteria: birth weight at least 2.5 kg, no sign of dysmorphic disease, stature less than the 3rd percentile for chronologic age (CA), linear growth velocity (GV) less than the 25th percentile for bone age (BA), no sign of puberty, maximal GH response to pharmacologic stimulation greater than 10 micrograms/L, no evidence of organic disease, treatment with daily subcutaneous administration of GH at a dose of 12 to 16 IU/m2 per week. MAIN OUTCOME MEASURES: Eight pretreatment growth variables and the increase of GV after 6 months of therapy were measured. Children with a change in GV that was greater than 2.5 cm/yr after 6 months of GH therapy were considered responders to GH. RESULTS: We studied 67 patients (44 boys). Forty patients (60%) were responders. With univariate analysis the variables found to have predictive value were GV (z score for gender and CA), bone age (z score for gender and CA), and percentage of ideal body weight. These variables were employed in a multivariate discriminant analysis. Growth velocity and BA showed the best independent discriminant analysis. Growth velocity and BA showed the best independent discriminant significance in predicting responsiveness to the initial 6 months of GH therapy. The obtained equation was as follows: Score = -0.40 + 0.92X1 - 0.87X2, where X1 is the GV z value for CA and X2 is the BA z value for CA). Using this scoring system, we obtained a specificity of 96.3% and a sensitivity of 92.5% in predicting responsiveness to GH (chi-square with Yates correction, 48.2; p < 0.001). CONCLUSIONS: Discriminant analysis may permit the pretreatment prediction of responsiveness to the initial 6 months of GH therapy in short children without GH deficiency.

Effect of insulin on hydrogen peroxide production by human polymorphonuclear leukocytes. Studies with monoclonal anti-insulin receptor antibodies, and an agonist and an inhibitor of protein kinase C.

This study evaluated the effect of insulin on the respiratory burst of human polymorphonuclear leukocytes (PMNLs) and the signalling pathways involved in this process, especially the involvement of protein kinase C (PKC). Isolated human PMNLs from healthy volunteers were incubated with different concentrations of insulin (10-10-10-7 mol/l) and for different durations of incubation (5-90 min). The intracellular production of hydrogen peroxide (H2O2) was detected employing a previously validated flow cytometric assay using 2',7'-dichlorofluorescein-diacetate (DCFH-DA) as a marker for H202 production. Specificity of insulin action was verified using an insulin antagonist (the monoclonal antibody MA-10). To identify the signalling pathway involved, we used; (a) monoclonal antibody MA-5, directed against the alpha-subunit of the insulin receptor, that partially mimics insulin without activating tyrosine kinase; (b) H7, an inhibitor of PKC involved in O2- production in PMNLs, and (c) phorbol myristate acetate (PMA) that binds and stimulates PKC. Insulin caused a dose- and time-dependent stimulation of H202 release by human PMNLs. The effect of insulin was blocked MA-10. The actions of insulin and PMA on H2O2 release were additive, whereas the actions of MA-5 and PMA were not. H7 partially inhibited the H2O2 production stimulated by insulin and completely inhibited MA-5 action. We conclude that insulin stimulates, in a dose- and time-related manner, the respiratory burst of human PMNLs. PKC activation can only partially account for the intracellular mechanisms involved in this process.

Reduced growth hormone secretion in Turner syndrome: is body weight a key factor?

The age-related decline in spontaneous growth hormone (GH) secretion has been suggested to cause growth failure in girls with Turner syndrome (TS). We studied 23 girls (mean age +/- SD: 11.1 +/- 2.7 years) diagnosed to have TS by karyotype analysis. The control group consisted of 18 prepubertal age-matched subjects (10.7 +/- 2.5 years) with growth retardation due to familial short stature and/or constitutional growth delay. In addition, 18 children (10.9 +/- 3.3 years) diagnosed to have GH deficiency by two different provocative tests were chosen as a further comparison group. Spontaneous 12-hour nocturnal GH secretion was assessed by RIA at 30-min intervals. Plasma insulin-like growth factor 1 (IGF-1) levels were determined by RIA after acid-ethanol extraction. Girls with TS had a percentage of ideal body weight significantly higher than controls (p < 0.0001) and showed spontaneous GH secretion significantly lower than controls (mean +/- SD: 3.2 +/- 1.6 in TS vs. 5.5 +/- 1.3 microgram/l in controls; p < 0.0001) but higher than GH-deficient patients (1.3 +/- 0.8 microgram/l; p < 0.0001). No significant difference was found in IGF-1 levels between TS patients and controls, whereas GH-deficient children showed IGF-1 levels significantly lower than those of TS patients (p < 0.0005). As expected, GH concentrations correlated with bone age in controls (r = 0.51, p < 0.05), whereas no relationship was seen in TS. interestingly, in TS, GH levels were negatively related to the percentage of ideal body weight (r = -0.43, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Increased chromosome fragility in lymphocytes of short normal children treated with recombinant human growth hormone.

A few years ago it was reported that some growth-hormone-deficient children had developed leukemia following therapy with human growth hormone. This raised concern that this therapy may stimulate tumor development. Since it is known that the tendency to develop cancer is closely related to chromosome breakage, we decided to investigate whether recombinant human growth hormone (rhGH) therapy can increase chromosome fragility. Ten short normal children were studied during their first year of treatment. Lymphocytes were collected at 0, 6 and 12 months of rhGH therapy, and we assessed the rate of spontaneous chromosome aberrations, the frequency of sister chromatid exchanges, the proliferative rate indices, the expression of common fragile sites induced by aphidicolin, and the sensitivity towards the radiomimetic action of bleomycin. At 6 months of therapy, there was a significant increase in bleomycin-induced chromosome aberrations, which remained unchanged after 1 year of treatment. An increase in spontaneous chromosome rearrangements at 6 and 12 months of therapy was also observed. These findings are further supported by data obtained from the analysis of 16 short normal children already on rhGH therapy.

Insulin-like growth factor binding protein 1 (IGFBP-1) levels in Turner syndrome.

We tested whether IGFBP-1, a modulator of IGF-I action, would play a role in the pathogenesis of growth failure and metabolic picture of Turner syndrome. Fasting serum levels of IGFBP-1 were assessed in nineteen girls with Turner syndrome (aging 6.5 to 17.2 years) by radioimmunoassay. Our patients showed normal values of IGFBP-1 (mean +/- SD: 68.6 +/- 32.5 micrograms/l, range: 16 to 134 micrograms/l; range for age and pubertal stage-matched normal children: 15 to 180 micrograms/l). IGFBP-1 levels inversely correlated with bone age (p < 0.05), weight (p < 0.001), percentage of ideal body weight (p < 0.002) and body mass index (BMI) (p < 0.001). Our results seem to rule out a role of IGFBP-1 in the pathogenesis of growth failure in Turner syndrome. The close inverse relationship between IGFBP-1 levels and BMI suggests the serum concentrations of IGFBP-1 to be regulated by the nutritional status. Due to IGFBP-1 inhibiting action on IGF biological activity, the reduction of IGFBP-1 levels in overweight subjects might represent a mechanism to enhance the IGF insulin-like activity, thus supplementing the insulin action.

Plasma levels of insulin-like growth factor binding protein-1, and growth hormone binding protein activity from birth to the third month of life.

Serum levels of insulin-like growth factors (IGF-1 and IGF-2), insulin, insulin-like growth factor binding protein-1 (IGFBP-1), growth hormone (GH) and growth hormone-binding protein (GH-BP) activity were assessed in a group of healthy newborns and reevaluated at one and three months of life in six of them. A significant decrease in IGFBP-1 plasma levels was observed at one month (p < 0.002) and three months (p < 0.02) of life compared to cord blood values. IGF-1 plasma levels did not change during the first three months of life. In contrast, IGF-2 plasma levels increased significantly at three months of life compared to cord blood values (p < 0.002). GH plasma levels showed a significant decrease at three months of life (p < 0.03). GH-BP activity was low at birth and did not change significantly during the first three months of life. The low GH-BP activity may reflect the GH receptor status, indicating that GH receptors are poorly expressed in early infancy. The high IGFBP-1 plasma levels in newborns could be important in protecting them from hypoglycemia.

GH assessment and three years' hGH therapy in girls with Turner syndrome.

Fifteen girls with Turner syndrome (TS) were submitted to GH secretion assessment before undergoing hGH therapy. In the first 9 months, hGH was given at a dose of 0.5 IU/kg/week s.c. daily; afterward, the dose was increased to 1 IU/kg/week s.c. daily. The girls were prepubertal, with a mean (SD) chronological age (CA) of 12.5 (2.6) years, and a mean (SD) bone age of 10.5 (1.8) years. A clonidine stimulation test, 1-29 GHRH test and GH spontaneous nocturnal secretion assessment were performed in all patients. Results showed a variable pattern of GH secretion in 10 patients, in only 2 did we find all values definitely normal, and in 3 we found a total GH deficiency. Height velocity, expressed as standard deviation scores (SDS) for CA according to Turner references, during the first year of treatment increased significantly: 0.36 (1.15) -3.30 (2.87) (p < 0.001), and the increment remained quite unchanged during both the second and third years: 3.16 (2.96) and 2.55 (3.87), respectively (n.s.). Height, expressed in SDS for CA for Turner references, increased significantly throughout the whole period of treatment and reached the highest value at the end of the third year of therapy. GH secretion parameters poorly correlated with pretreatment auxological data or response to treatment. Our long-term study confirms that in TS GH measurement is not useful in indicating hGH therapy or in predicting the response.

Enhancement by growth hormone of phorbol diester-stimulated respiratory burst in human polymorphonuclear leukocytes.

The oxidative metabolic burst of mononuclear and polymorphonuclear phagocytes can be stimulated to produce free oxygen radicals. Several substances can enhance this respiratory burst activity by a priming action: recently growth hormone (rat and porcine) was demonstrated to act as a priming agent on rat peritoneal and on porcine alveolar macrophages. In our study we wanted to verify whether also human GH had a similar priming action on homologous cells, in particular on polymorphonuclear leukocytes. To determine the oxidative activity of polymorphonuclear leukocytes, after stimulation with phorbol myristate acetate, a flow-cytometric assay was employed which registered the intracellular formation of highly fluorescent products as indicators for the intracellular formation of hydrogen peroxide. The incubation of phorbol myristate acetate-stimulated polymorphonuclear leukocytes with GH resulted in a time-dependent and dose-dependent increase in fluorescence, thus demonstrating that human GH enhances in vitro the oxidative metabolic burst of these cells. The action of GH appeared to be significant after 30 min of incubation, was maximal at 60 min, and decreased after 90 min. After one hour of incubation, the first significant variation of fluorescence appeared with GH at a concentration of 50 micrograms/l. The maximum effect was seen at 100 micrograms/l with no further increase. Specificity of GH action was demonstrated by the inhibition of its effect by the addition of monoclonal antibodies to GH.

Immune function in growth hormone-deficient children treated with biosynthetic growth hormone.

Conflicting data regarding the immune function in growth hormone (GH) -deficient children or changes in immune parameters during substitutive GH therapy have been reported. We have studied the immune function in 13 patients with GH deficiency before and during treatment with biosynthetic GH (12 IU/m2 body surface/week) after 6 and 12 months of therapy. We found that the absolute number of total T lymphocytes and T-cell subsets (using monoclonal Ab as markers), Natural Killer cell activity (target K562) and response of lymphocytes to polyclonal mitogens (PHA, ConA, PWM) were all in the normal range and remained so after 6 and 12 months of therapy. The absolute number of B lymphocytes was in the normal range before treatment and after 6 months of therapy but dropped significantly after 12 months of treatment. Serum immunoglobulins (IgG, IgA, IgM) did not show a parallel drop and remained normal throughout the whole study. Our GH-deficient patients did not show any undue susceptibility to infections and our data thus seem to confirm that the immune function is basically intact in these children and that it is not suppressed by GH treatment. Although a drop in B lymphocytes was observed, the normal level of immunoglobulins and the normal functional response to PWM seem to demonstrate the maintenance of a normal humoral immune response.

Long term growth hormone (GH)-releasing hormone and biosynthetic GH therapy in GH-deficient children: comparison of therapeutic effectiveness.

Twenty-five GH-deficient children were treated with GHRH (1-44), once daily sc for 6-24 months. At the 6th month of therapy, 40% of our patients showed a catch-up growth (responders), while the remaining 60% did not (nonresponders). No differences in auxological and biological variables at inclusion were found between the two groups. However, integrated GH secretion elicited by iv GHRH at inclusion was significantly (p less than 0.025) higher in responders than in non responders. During GHRH therapy, no significant increase in IGF 1/SmC was found in both groups. In all patients treatment was discontinued after 6-24 months, when its effect on growth rate failed. After a wash-out period of at least 6 months, patients were submitted to biosynthetic GH therapy. After 6 months of GH treatment a significant catch-up growth was found in both responder and non-responder children. Although the majority of GH-deficient children have hypothalamic rather than pituitary dysfunction, GHRH therapy is found to be less effective than GH treatment. Other methods of GHRH administration are worth investigating.