Normal Growth Hormone Peak Research Articles

Vitamin D content in children with short stature due to intrauterine growth restriction against normosomatotropinemia

Background. There are no data about the status of vitamin D and its effect on the growth hormone/growth factors axis in prepubertal children with intrauterine growth restriction (IGR). Of particular interest is a group of patients who remain significantly short on the background of a decrease in insulin-like growth factor 1 (IGF-1) levels and normal stimulated release of growth hormone (GH). The purpose of our study was to determine the levels of 25-hydroxycalciferol in the blood plasma of prepubertal children with short stature due to IGR on the background of normosomatotropinemia. Materials and methods. We examined 34 prepubertal children (14 girls and 20 boys) with short stature (average age — 6.95 ± 0.46 years) who had signs of IGR at birth. A symmetrical type of IGR was found in 15 (44.2 %) patients, an asymmetrical type — in 19 (55.8 %). According to the results of functional tests all patients had a normal GH peak release (> 10 ng/ml). Thyroid-stimulating hormone, free thyroxine levels in the blood plasma were determined by the immunoradiometric assay with standard Immunotech® kit (Czech Republic). At the time of examination, all patients were euthyroid. GH, IGF-1 and insulin-like growth factor binding protein 3 (IGFBP-3) levels were determined by enzyme-linked immunosorbent assay using Immulite 2000 Xi kits (Siemens, USA). 25-hydroxycalciferol level was determined by the immunochemiluminescent method (Abbott, USA). The results were evaluated according to the guidelines of the International Society of Endocrinology (2011). Results. It was found that in prepubertal children with IGR signs at birth, the average height standard deviation score (SDS) at the time of the examination was –2.83 ± 0.12. There were no significant differences between the height and body weight in patients with a symmetrical and an asymmetrical types of IGR at the time of examination (p > 0.05). Vitamin D content in the blood plasma of children with IGR signs was 49.70 ± 2.17 nmol/l in the whole group. Vitamin D insufficiency below 75 nmol/l was found in 16 (47 %) patients, and vitamin D deficiency below 50 nmol/l — in 18 (53 %). No significant differences were found between vitamin D values in girls and boys with signs of IGR (51.79 ± 3.38 nmol/l and 48.36 ± 2.86 nmol/l, respectively, p > 0.05). Height SDS in the group of patients with an asymmetrical type of IGR weakly correlates (r = 0.38) with vitamin D content. Vitamin D level significantly differed depending on IGR type (in a symmetrical type — 44.1 ± 3.2 nmol/l, in an asymmetrical type — 54.20 ± 2.56 nmol/l, p < 0.05). IGF-1 SDS in the group of patients with an asymmetrical type of IGR weakly correlated (r = 0.36) with vitamin D level. On the background of a significant decrease in IGFBP-3 content in children with an asymmetrical type of IGR compared to those with a symmetrical type (–1.32 ± 0.07 SDS and –1.00 ± 0.14 SDS, p < 0.05), there was a reduction in IGF-1 levels (–1.62 ± 0.10 SDS and –1.34 ± 0.14 SDS, p = 0.05). Conclusions. Patients born with signs of IGR, even against normosomatotropinemia, may still have significant growth deficit, a sharp decrease in IGF-1 and IGFBP-3 for a long time after birth. The results obtained indicate the presence of hypovitaminosis D in all prepubertal patients who were born with the signs of intrauterine growth restriction. No correlation was found between vitamin D level and the maximum peak of stimulated growth hormone release. However, patients with an asymmetrical type of IGR have a weak correlation (r = 0.36) between IGF-1 SDS and vitamin D content, a significant decrease in the content of IGF-1, IGFBP-3, as well as vitamin D compared to its level in a symmetrical type of IGR. It is recommended to include the determination of vitamin D level in the blood plasma irrespective of the type of disease and the state of somatotropic function in the list of studies for the examination of children with short stature who were born with signs of intrauterine growth restriction.

P1.03: Intravenous glucose nocturnal infusion reduces growth hormone secretion in children on total parenteral nutrition

Introduction: Most children with intestinal failure (IF) benefit from home parenteral nutrition (HPN). It allows a familial life with normal children activities such as going to school, sports, and being at home. In order to do so, PN is provided with cyclic infusion at night. Children with IF on HPN should have normal growth. However, some children grow under their genetic target height and present with decreased height velocity. Methods: We report the case of two children on HPN who presented with decreased height velocity while their weight gain was normal. After ruling out usual etiology (insufficient protein intake, acidosis, sodium deficiency, IFALD…), growth hormone (GH) deficiency was considered. Extensive testings were performed such as IgF1 levels, GH secretion stimulation test and nocturnal GH secretion. PN dependency was assessed using the PN/REE index (parenteral nutrition non-protein energy intake divided by resting energy expenditure calculated using Schofield equation, expressed in percentage). Results: These two children needed extremely high PN caloric intake to achieve a normal weight gain with a PN dependency index of 163% and 150%. Table 1 shows their clinical characteristics. Table 2 shows the results of the biological testings. These two children showed a normal GH peak under stimulation, but a low nocturnal GH secretion meaning they were able to produce GH under stimulation, but their nocturnal physiological secretion was inhibited. Their mean glycemia during PN perfusion was high compared to fasting glycemia which should normally be observed at night in children. Hyperglycemia is a well known inhibitor of GH secretion. Conclusion: Children with very high PN dependency are at risk of developing reduced height. In some children, GH secretion seems to be inhibited by nocturnal high glucose infusion. A longer PN infusion time can be proposed and/or a decrease in glucose intake with an increase in lipid intake. Also, growth hormone supplementation might be discussed and should be evaluated in this setting.

Growth Hormone Response to Standard Provocative Stimuli and Combined Tests in Very Young Children with Prader-Willi Syndrome

Background: In Prader-Willi syndrome (PWS) a reduced growth hormone (GH) response to several stimulators has been documented in many studies, but none have focused on very young children. We evaluated the pattern of GH secretion in very young PWS patients. Patients and Methods: Twenty-seven genetically confirmed PWS children (10 females, aged 0.4-5 years, mean: 2.2 ± 1.4 years) were included. All subjects underwent standard provocative tests (clonidine, CLO; and arginine, ARG) and one combined test [growth hormone-releasing hormone (GHRH) plus pyridostigmine (13 patients) or GHRH plus arginine (14 patients)]. Insulin-like growth factor-1 (IGF-1) levels were also measured. Results: While standard tests (CLO and ARG) showed low GH peak in 85.2 and 70.4% of the patients, respectively, the combined test was found to be normal in 85.2%. IGF-1 was low in 66.7% of patients. Out of 27 patients, 3 (11%) showed a normal GH peak with both standard tests (group A), 6 (22%) to one of the standard tests (group B) and 18 (67%) presented a low response to both standard tests (group C). Four subjects showed low response to both the combined and standard tests and reduced IGF-1. Conclusion: Our data suggest that very young PWS children seem to have impaired hypothalamic GHRH secretion with a normal GH pituitary reserve.

Do IGF-I concentrations better reflect growth hormone (GH) action in children with short stature than the results of GH stimulating tests? Evidence from the simultaneous assessment of thyroid function

BackgroundThe diagnosis of growth hormone (GH) deficiency (GHD) in short children seems unquestionable when both GH peak in stimulating tests (GHST) and IGF-I concentration are decreased. However, the discrepancies between the results of GHST and IGF-I secretion are observed. It seems purposeful to determine the significance of GHST and IGF-I assessment in diagnosing GHD. The relationship between GH secretion and thyroid function, as well as GH influence on the peripheral thyroxine (T4) to triiodothyronine (T3) deiodination, mediated by IGF-I, were identified. Thus, clear differences in thyroid function between GH-deficient and non-GH-deficient subjects should exist.MethodsAnalysis comprised 800 children (541 boys), age 11.6 ± 3.1 years (mean ± SD), with short stature, in whom two (2) standard GHST (with clonidine and with glucagon) were performed and IGF-I, free T4 (FT4), free T3 (FT3) and TSH serum concentrations were assessed. The patients were qualified to the following groups: GHD - decreased GH peak in GHST and IGF-I SDS (n = 81), ISS - normal GH peak and IGF-I SDS (n = 347), low GH - normal IGF-I SDS, and decreased GH peak (n = 212), low IGF - decreased IGF-I SDS, and normal GH peak (n = 160). The relationships among the results of particular tests were evaluated.ResultsIn the groups with decreased IGF-I concentrations (GHD Group and low IGF Group), the more severe deficit of height was observed, together with higher TSH and FT4 but lower FT3 levels than in groups with normal IGF-I concentrations (ISS Group and low GH Group), independently of the results of GHST. TSH, FT4 and FT3 concentrations were - respectively - similar in two groups with decreased IGF-I secretion, as well as in two groups with normal IGF-I levels. Significant correlations were found between patients' height SDS and IGF-I SDS, between FT3 and IGF-I SDS (positive), and between FT4 and IGF-I SDS (negative), with no correlation between GH peak and any of the parameters analyzed.ConclusionThe assessment of thyroid function in children with short stature provides the evidence that measurement of IGF-I concentration may be a procedure reliable at least to the some degree in diagnosing GHD as the results of GHST.

Growth hormone response to arginine test differentiates between two subgroups of Huntington's disease patients

ObjectiveHuntington's disease (HD) is an autosomal dominant disorder characterised by motor, cognitive and psychiatric disturbances. Several studies have demonstrated that hypothalamic dysfunction is part of the phenotypic spectrum. The aim...

Diagnosis of growth hormone (GH) deficiency: comparison of pituitary stalk interruption syndrome and transient GH deficiency

BackgroundMost patients with childhood non-organic growth hormone (GH) deficiency (GHD) produce a normal GH peak as young adults. Our objectives were to better define this transient GHD and evaluate the factors influencing the growth response of patients with pituitary stalk interruption syndrome (PSIS).MethodsWe studied 72 prepubertal patients with a GH peak < 6.7 ng/ml after 2 stimulation tests, treated with 0.2 mg GH/kg/w for at least 3 years. Group 1 (n = 53, 4.7 ± 4.0 years) had PSIS and Group 2 (n = 19, 9.2 ± 3.0 years) had transient GHD and normal pituitary.ResultsAt diagnosis, 64% of Group 1 and one Group 2 were < 5 years old. The growth rate of 59% Group 1 and two Group 2 patients was ≤ -2 SDS. The GH peak of 64% Group 1 patients and no Group 2 patients was < 3 ng/ml. The plasma insulin-like growth factor-1 of all Group 1 and all but one Group 2 patients was ≤ -2 z scores.During the first year of GH treatment, the growth rate was ≥ 2 SDS in 81% Group 1 and 37% Group 2 patients. In Group 1, it was negatively correlated with the GH peak before treatment (P < 0.03), and with the difference between the target and adult heights (P < 0.01).The height gain SDSs between diagnosis and adult height were 1.7 ± 1.2 in Group 1 (n = 30) and 1.08 ± 0.8 in Group 2 (n = 12, P = 0.05).ConclusionThe factors of the growth response to GH treatment should be analysed separately for each population: with and without PSIS or other markers.

Response to Long-Term Growth Hormone Therapy in Short Children with Reduced GH Bioactivity

Background/Aims: The aim of the present study was to investigate whether short children with normal growth hormone (GH) immunoreactivity, but reduced bioactivity (bioinactive GH) could benefit from rhGH treatment as GH deficient (GHD) patients. Methods: We evaluated 12 pre-pubertal children (8 M, 4 F), with GH deficiency-like phenotype showing normal serum GH peak levels (>10 ng/ml), measured by immunofluorimetric assay (IFMA-GH), in contrast with a reduced GH bioactivity (bio-GH), evaluated using the Nb₂ cells. We also evaluated 15 age-matched GHD pre-pubertal children (11 M, 4 F) with serum GH peak <5 ng/ml. Both groups were treated with rhGH therapy at the dose of 0.23 mg/kg/week s.c. Results: Serum bio-GH/IFMA-GH ratio at peak time for each patient during the provocative test was significantly lower in bioinactive GH than in GHD children (0.29 vs. 2.05, p = 0.00001). Recombinant human GH therapy induced a significant (p < 0.001) increase in growth rate in both groups during the first 2 years. In the third year of treatment, while growth rate in GHD children is maintained, in bioinactive GH patients it decreases remaining, however higher compared to the pre-treatment one. Conclusions:Short rhGH therapy given to selected bioinactive GH children improve growth rate and might result in greater final adult height.

Management of Boys with Short Stature and Delayed Puberty

To review the management of boys with short stature and delayed puberty and the testosterone priming protocol. In 148 boys aged > 14 years seen for height < -2 SDS and constitutional delayed puberty we evaluated growth hormone (GH) secretion and final height (80 boys). The GH peak was < 10 microg/l after arginine-insulin tests performed with testosterone heptylate priming in 8/32 (25%) and without in 62/153 (41%), including first and second evaluations. It was low in 7/11 boys given 2 x 100 mg testosterone (14.7 +/- 1.7 microg/l) and in 1/21 given 4 x 100 mg (21.3 +/- 2.0 microg/l, p = 0.04). It was low during sleep in 4/29 (14%) boys, all having basal plasma testosterone below 3.5 nmol/l. The basal insulin-like growth factor (IGF)-I concentration was below -2 SDS in 22% of the boys evaluated. Final height was -0.8 +/- 0.1 SDS. It was similar in those with low (n = 9) and normal (n = 71) GH peak, and in those treated (n = 22) or untreated (n = 58) with testosterone. It was over 1 SDS lower than the target height in 20% and than the predicted height at the initial evaluation in 14% of the boys. Pubertal growth was not correlated with the GH peak or plasma IGF-I. The GH peak during the sleep is more frequently normal than the peak after stimulation. The number of testosterone doses influences the quality of priming. The medical problems involved in treating boys with delayed puberty are excluding disease and deciding on testosterone treatment.

Assessing Short-Statured Children for Growth Hormone Deficiency

Aim: To optimize the workup of short-statured children by defining the most appropriate tools for diagnosing growth hormone (GH) deficiency. Methods: Patients were assigned to prepubertal (n = 113) or pubertal (n = 112, including 25 boys primed with testosterone) age groups. Mean plasma GH concentration during sleep, GH peak after provocative test, and insulin-like growth factor I (IGF-I) were measured in a single evaluation. Results: The mean GH concentration during sleep was more often normal (n = 155) than the GH peak after provocative tests (n = 105) or the IGF-I concentration (n = 88). Prepubertal patients with a normal body mass index (BMI) had mean GH concentrations during sleep that correlated positively with height, growth rate, GH peak after provocative tests, and IGF-I (p < 0.0005 for all) and negatively with the difference between target and patient heights (p = 0.01) and BMI (p < 0.05). Pubertal patients with a normal BMI had a mean GH concentration during sleep that correlated positively with GH after provocative tests (p < 0.0001) and IGF-I (p < 0.005). Mean GH concentration during sleep and IGF-I concentration for boys primed with testosterone were more often normal (n = 23) than the GH peak after provocative tests (n = 14). All 9 patients with pituitary stalk interruption had low IGF-I concentrations; 1 patient had a normal GH peak after provocative test, and 2 patients had normal mean GH concentrations during sleep. Conclusions: Measuring the GH concentration during sleep and priming boys with pubertal delay can help to exclude idiopathic GH deficiency. Magnetic resonance imaging is needed to exclude anatomic abnormalities when GH and/or IGF-I concentrations are low.

Growth Hormone Deficiency: Permanence and Diagnosis in Young Adults

Objective: To optimize the tools for diagnosing idiopathic growth hormone (GH) deficiency. Methods: We compared the data of 43 young adults treated for GH deficiency before and after GH treatment and puberty. Those with organic lesions were assigned to group 1 (n = 9), those with certain GH deficiency (n = 11) to group 2 and those with no criterion of certitude of GH deficiency to group 3 (n = 23). Results: Group 1 patients: the GH peaks at first [1.5 ± (SE) 0.4 µg/l] and second (1.9 ± 0.7 µg/l) evaluations before treatment were similar to those at the third evaluation (1.2 ± 0.8 µg/l) after treatment. Group 2 patients: they had similar peaks (2.6 ± 0.8, 2.9 ± 0.5 and 5.5 ± 1.4 µg/l). Group 3 patients: the peaks increased from 4.9 ± 0.4 and 4.8 ± 0.4 to 18.4 ± 2.3 µg/l (p < 0.0001); 87% had a GH peak >10 µg/l at this evaluation. The plasma insulin-like growth factor 1 was initially below –2 z-score in 12/13 of these patients and similarly low in 4/17 patients at the third evaluation. The growth rates of the three groups before and their increase during the 1st year of treatment were similar. Conclusion: Almost all patients with GH deficiency before puberty without criteria of certitude had a normal GH peak after puberty. Some of these patients probably had a transiently low GH secretion.

Defective growth hormone (GH) secretion and short-term treatment in Noonan syndrome.

Auxological and endocrine data from 12 prepubertal children (3 males, 9 females) with Noonan syndrome (NS) were compared with those of 15 children with constitutional short stature (CSS), 20 children with partial GH deficiency (GHD), and 6 children with Turner syndrome (TS). Four children with NS were treated with human growth hormone (hGH) (n = 4) (25 units/m2 week, divided on daily s.c. doses). In children with NS, the peak serum GH response to clonidine (5.4 +/- 2.7 ug/L) and glucagon (7.4 +/- 3.4 ug/L) were significantly lower than those for children with CSS (14.8 +/- 3.4 and 12.8 +/- 2.8 ug/L respectively). Nine out of the 12 (75%) children with NS did not mount normal GH peak (10 ug/L or more) after provocation. The 12-h integrated GH secretion in the 3 children with NS who had normal GH response to provocation (2.7 +/- 0.7 ug/L) was markedly lower compared to that for children with CSS (6.7 +/- 1.2 ug/L). The serum insulin-like growth factor-1 (IGF-I) concentrations were lower in children with NS (67 +/- 32 ng/ml) vs CSS (165 +/- 35 ng/ml), but not different from those for GHD children (59 +/- 33 ng/ml). In 4 children with NS, hGH therapy for a year increased height growth velocity from 4.1 +/- 0.3 cm/yr to 7.4 +/- 0.6 cm/yr and height standard deviation score (Ht SDS) from -2.2 +/- 0.6 to -1.45 +/- 0.3. This growth acceleration was accompanied by an increase in IGF-I concentration (from 52 +/- 21 ng/ml to 89 +/- 25 ng/ml). In summary, these results prove a defect of the GH secretion in children with NS and suggest that GH therapy has an important role in the management of their short stature.

Growth hormone secretion, puberty and adult height after cranial irradiation with 18 Gy for leukaemia.

The dose of prophylactic cranial irradiation given to patients for acute lymphoblastic leukaemia has been decreased from 24 to 18 Gy, but the beneficial effect of this decrease on growth is controversial. This study compares the growth hormone (GH) secretion and growth of 35 patients (20 boys) given 18 Gy at 3.7+/-0.3 (SE) years, and routinely evaluated 5.4+/-0.4 years after irradiation to define the indications for GH treatment in these patients. Of these, 63% had a low GH peak (< 10 microg/l) after one (22 cases) or two (17 cases) stimulation tests. The plasma concentrations of insulin-like growth factor I and its GH-dependent binding protein were normal for age in all but two cases. The height changes between irradiation and evaluation were correlated with the GH peaks (P < 0.03) and were concordant, except in patients with early puberty. This occurred in 16 patients including all 12 girls irradiated before 4 years of age. A significant (P < 0.03) reduction in height (SD) between irradiation and adult height occurred in untreated GH-deficient patients (-1+/-0.3, n=6), but not in GH-deficient patients given GH (-0.6+/-0.3, n=8) or in those with normal GH peak (-0.4+/-0.3, n=7). In children irradiated for acute lymphoblastic leukaemia, GH deficiency is frequent after 18 Gy but its impact on adult height is smaller than after higher doses. We suggest that the indications for gonadotropin releasing hormone analogue therapy should be broad in patients with early or rapidly progressing puberty and those for GH therapy in those patients with a below average constitutional height before irradiation.

Adult height after cranial irradiation with 24 Gy: factors and markers of height loss.

The decrease in adult height of children who have been given cranial irradiation (24 Gy) for acute lymphoblastic leukaemia is attributed to chemotherapy, growth hormone (GH) deficiency and early puberty. This study evaluates the factors involved in the height loss between irradiation and adult height and its markers in 43 patients irradiated at 5.8 +/- 0.4 (SEM) years. The mean height loss was 0.9 +/- 0.2 SD in the children with a normal GH peak (n = 11), 1.7 +/- 0.2 SD in those with a low GH peak and untreated (n = 15) and 0.6 +/- 0.2 SD in those treated with GH (n = 17). The adult height was significantly lower than target height in all three groups. The height loss correlated negatively with the GH peak (p < 0.02) and with the age at onset of puberty (p < 0.05) in the first two groups with spontaneous growth, but not with the chemotherapy regimen or its duration, or the plasma insulin-like growth factor I (IGFI) and its GH-dependent binding protein (BP-3). Early puberty (onset at 8-10 years) occurred in 6 girls from the first two groups. At the first evaluation, 5.6 +/- 0.4 years after irradiation, the GH peak values after arginine-insulin stimulation correlated with the age at irradiation (p < 0.03), taking into account the time since irradiation. The plasma IGFI and BP-3 values were correlated with each other, but not with the GH peak. In conclusion, this study demonstrates the impact of GH deficiency and GH replacement therapy on adult height in children given cranial irradiation for leukaemia. They therefore should be evaluated for their GH secretion 1-2 years after the end of chemotherapy. GH therapy is indicated for those with low GH peak and decreased growth rate or no increase in growth rate despite puberty.

A new test for the diagnosis of growth hormone deficiency due to primary pituitary impairment: combined administration of pyridostigmine and growth hormone-releasing hormone

The diagnosis of growth hormone (GH) deficiency (GHD) is currently based on failure to increase plasma GH levels to an arbitrary cutoff point of 7 or 10 micrograms/l in response to two provocative stimuli. False negative responses to these tests, however, frequently occur thus reducing their diagnostic reliability. The aim of this study was to assess a combination of pyridostigmine (PD) and GH-releasing hormone (GHRH) (60 mg oral PD 60 min before 1 microgram/Kg GHRH iv) as a reliable test probing pituitary somatotropic function. In fact PD, an acetylcholinesterase inhibitor, strikingly potentiates GH response to GHRH likely by inhibiting somatostatin release. The combination PD + GHRH was tested in normal children and adolescents (NS, n = 27) and in a large group of short children classified as having familial short stature (FSS, n = 24), constitutional growth delay (CGD, n = 34) and GH deficiency (organic, oGHD, n = 6; idiopathic, iGHD, n = 10). In all groups results obtained by PD + GHRH were compared with those obtained by testing with GHRH, clonidine (CLON) and PD alone and by studying spontaneous nocturnal GH secretion over 8 hours. Assuming 7 micrograms/l as minimum normal GH peak, a positive response occurred in only 18/24, 11/12 and 12/13 NS for GHRH, CLON, and PD, respectively. In contrast even assuming a minimum normal GH peak as high as 20 micrograms/l, PD + GHRH induced a positive response in 27/27 NS all having a nocturnal GH mean concentration (MC) greater than or equal to 3 micrograms/l. Therefore PD + GHRH test gave no false negative responses and this was true not only in NS but even in all FSS and CGD having a GH MC greater than or equal to 3 micrograms/l. On the other hand, PD + GHRH induced a negative GH response in all oGHD and in 8/10 iGHD patients. In the remaining two iGHD patients, PD + GHRH demonstrated a normal pituitary GH reserve in spite of a GH MC less than 3 micrograms/l and low IGF-I level, thus pointing to a hypothalamic pathogenesis for the GHD. Considering FSS and CGD children having a GH MC less than 3 micrograms/l, PD + GHRH showed a primary pituitary GH deficiency in 3/12 CGD with low plasma IGF-I levels. In conclusion, in slowly growing children PD + GHRH test is the most reliable provocative test for the diagnosis of primary pituitary GH deficiency being capable to discriminate between an unequivocally normal and impaired somatotropic function.(ABSTRACT TRUNCATED AT 400 WORDS)