Methionyl human growth hormone in Turner's syndrome

Analysis of new growth promoting black market products

Detecting agents allegedly or evidently promoting growth such as human growth hormone (GH) or growth hormone releasing peptides (GHRP) in doping controls has represented a pressing issue for sports drug testing laboratories. While GH is a recombinant protein with a molecular weight of 22 kDa, the GHRPs are short (3-6 amino acids long) peptides with GH releasing properties. The endogenously produced GH (22 kDa isoform) consists of 191 amino acids and has a monoisotopic molecular mass of 22,124 Da. Within this study, a slightly modified form of GH was discovered consisting of 192 amino acids carrying an additional alanine at the N-terminus, leading to a monoisotopic mass of 22,195 Da. This was confirmed by top-down and bottom-up experiments using liquid chromatography coupled to high resolution/high accuracy mass spectrometry. Additionally, three analogues of GHRPs were identified as Gly-GHRP-6, Gly-GHRP-2 and Gly-Ipamorelin, representing the corresponding GHRP extended by a N-terminal glycine residue. The structure of these peptides was characterised by means of high resolution (tandem) mass spectrometry, and for Gly-Ipamorelin and Gly-GHRP-2 their identity was additionally confirmed by custom synthesis. Further, established in-vitro experiments provided preliminary information considering the potential metabolism after administration.

The growth pattern and final height of girls with Turner syndrome with and without human growth hormone treatment

BACKGROUND

Shortness is the most frequent and quite disturbing characteristic of girls with Turner syndrome (TS). Human growth hormone administration (hGH) to girls with TS increases growth velocity (GV), but a favorable effect on final height (FH) has not been documented. The aim of this study was to evaluate the effect of hGH administration on the growth pattern and FH in girls with TS.

METHODS

The study group was comprised of 123 girls with TS who were cared for in our center. Eighty-two of these girls received hGH (mean dose, 0.78 +/- 0.12 IU/kg/week), given subcutaneously 5 to 7 times per week for a period of 2.2 +/- 1.2 years (hGH group). The mean chronological age (CA) and bone age (BA) at hGH initiation were 11.5 +/- 2.5 years and 9.7 +/- 2.3 years, respectively. The remaining 41 girls did not receive hGH and are designated as the untreated control group. In both groups, gonadal steroids were given for pubertal initiation and maintenance.

RESULTS

The GV during the first year of hGH therapy (GV1) was higher than the year before hGH (6.3 cm/year vs 4.0 cm/year) and higher than the GV of the untreated group at a similar CA (4.4 cm/year). The GVs during the second (GV2) and third (GV3) year of hGH treatment (5.4 and 4.9 cm/year, respectively) were lower, but still higher in the hGH group, in comparison with the untreated group (GV2, 4.2 cm/year; GV3, 3.4 cm/year). GV1, GV2, and GV3 were negatively related to age and to BA at hGH initiation. The FH of the 35 hGH-treated girls was not significantly different from the FH of the 27 untreated girls (146.1 cm vs 144.0 cm). The Delta target height-FH was not significantly different in the two groups. The FH standard deviation score of the hGH-treated group was positively related to height standard deviation score for CA at treatment initiation (r = +0.73), maternal height (r = +0.57), target height (r = + 0.66), and birth weight (r = +0.54), but was unrelated to CA or BA at start of therapy or to hGH dose.

CONCLUSIONS

hGH therapy in girls with TS, in the dose and duration of treatment applied in this study, significantly accelerated GV but did not significantly improve FH.

Human growth hormone treatment in prepubertal children with achondroplasia

We studied the effects of recombinant human growth hormone (GH) treatment in 6 prepubertal children with achondroplasia. The patients' age ranged from 2 11/12 to 8 5/12 years and the GH dose was of 0.1 IU/kg/day subcutaneously. Auxological assessments and bone age determinations were performed 6 months before, at the beginning, and after 6 and 12 months of therapy. The growth velocity increase during the whole year of treatment ranged from 1.1 to 2.6 cm/year in 3 patients while in the others no variation was detected. No side effects were observed during the trial apart from a slight advancement of bone age in two patients. MRI at the cervicomedullary junction and CT scan of the base of the skull did not show any variation of the dimensions of the foramen magnum at the end of the trial compared to baseline. Our study shows that r-hGH can safely increase short-term growth velocity in some but not all prepubertal children with achondroplasia. Our data confirm the individual variability in the response to the GH treatment.

Guidelines for the use of growth hormone in children with short stature. A report by the Drug and Therapeutics Committee of the Lawson Wilkins Pediatric Endocrine Society

On the basis of the information currently available, the only conditions in which GH therapy appears to be safe and effective in increasing adult height are GH deficiency and, likely, Turner syndrome. Therapy with GH also increases the growth velocity of children with CRI and may increase adult height, but no long-term data are available. Encouraging short-term results have been reported in patients with a few other conditions, such as patients with glucocorticoid-induced growth failure, renal transplantation, and Prader-Willi syndrome, but the data are limited and no long-term studies have been reported; in many other conditions the data are either inconclusive or discouraging. For children in these latter groups, GH therapy should be considered investigational and undertaken only as part of ethically sound, controlled clinical trials. Knowledge concerning the conditions in which GH is safe and effective is a prerequisite to making rational decisions concerning its use. However, in deciding whether therapy is warranted in an individual child, one must consider other important factors. The age and emotional maturity of the child, the family structure and dynamics, and even financial considerations may, in some cases, outweigh the presence of a GH-responsive condition. Likewise, the child's and the family's views about "short" stature and the likely benefits of therapy must be considered. Ultimately, a decision concerning the appropriateness of GH therapy must be individualized and based on a realistic assessment of its impact on the quality of life of the child and future adult.

Treatment of patients with Ullrich-Turner syndrome with conventional doses of growth hormone and the combination with testosterone or oxandrolone: effect on growth, IGF-I and IGFBP-3 concentrations

Thirty-nine girls with Ullrich-Turner syndrome (UTS) (median age 9.5 years) were treated with growth hormone (GH) with either 12 or 18 IU/m2 per week for 12 months followed by combination therapy with either oxandrolone (Ox) (0.0625 mg/kg/day po) or low-dose testosterone (T) (5 mg in every 2 weeks). Growth velocity improved significantly after 12 IU/m2 per week (6.4 +/- 1.7 cm/year vs 4.0 +/- 1.3 cm/year, x +/- SD, P < 0.001) and 18 IU/m2 per week of GH (6.5 +/- 1.3 cm/year vs 4.5 +/- 1.4 cm/year, P < 0.001). Ox, but not T was effective in maintaining growth velocity during the 2nd year of therapy (6.9 +/- 1.3 vs 5.3 +/- 1.5 cm/year). Basal insulin-like growth factor-I (IGF-I) concentrations were in the lower normal range and increased significantly in patients treated with 18 IU/m2 per week (357 +/- 180 ng/ml vs 160 +/- 84 ng/ml) and 12 IU/m2 per week (273 +/- 121 ng/ml vs 140 +/- 77 ng/ml). IGF-I concentrations increased further after addition of Ox (533 +/- 124 ng/ml, P < 0.001) or T (458 +/- 158, P < 0.05). IGFBP-3 concentrations were in the upper normal range before therapy and increased only moderately in both GH dosage groups. However, IGF binding protein-3 (IGFBP-3) concentrations were not affected by additional Ox or T treatment.

CONCLUSIONS

1. Conventional GH doses are effective in increasing growth velocity in UTS, especially, when combined with Ox.(ABSTRACT TRUNCATED AT 250 WORDS)

Use and abuse of human growth hormone

Recombinant human growth hormone (hGH) has been available for nearly a decade. Side effects are rare. Its efficacy in promoting growth acceleration has been widely confirmed in children with GH deficiency (GHD), Turner syndrome, idiopathic short stature, chronic renal failure, and a variety of other conditions. The dramatic increase in height velocity in the first year of therapy partially attenuates in subsequent years in all patient groups, and convincing final height data are only available in GHD and Turner syndrome. Pediatric endocrinologists continue to be troubled by definitions of GHD. Although profound GHD is relatively obvious, other patients with severe growth failure but borderline or normal endocrine testing also respond to hGH therapy. Thus many endocrinologists use auxologic criteria [e.g. low growth velocity, height < -3 standard deviation (SD), poor predicted adult height] as the de facto basis for therapy, leading to a blurred distinction between treatment of disease and enhancement of normal characteristics and, finally, raising questions about the ultimate benefit of hGH therapy. Brief clinical trials of hGH therapy in adults both with and without GHD have reported increased muscle mass, decreased fat, and improvement in quality of life. Internists may soon be faced with treatment decisions analogous to those confronting pediatricians, i.e. whether to use hGH to repair aspects of the normal aging process.

Demography, auxology and response to recombinant human growth hormone treatment in girls with Turner's syndrome in the Kabi Pharmacia International Growth Study. International Board of the Kabi Pharmacia International Growth Study

Demographic and auxological data were analysed from 818 girls with Turner's syndrome treated with recombinant human growth hormone (GH) and entered into the Kabi Pharmacia International Growth Study. Size at birth was low and correlated with the heights of both parents. The median age at start of GH treatment was 11.4 years and the parents had a median height SDS of -2.9. Height SDS at the start of treatment correlated with parental heights. Height velocities conformed to Turner-specific standards. The weight-for-height index increased sharply above 9 years of age. The frequency of spontaneous appearance of Tanner breast stage 2 was high (34.1% of girls > 10 years of age). Bone age (Greulich and Pyle) data were described by the equation: bone age = 1.61(chronological age) - 0.04(chronological age)2 - 3.61. This equation was used to correct adult height predictions. The median initial dose of GH was 0.8 IU/kg/week and was maintained during the first 3 years of treatment. The median frequency of injections was six/week. Height velocity increased from 4.1 to 6.8 cm/year in the first year, and height velocity SDS for chronological age remained positive for 4 years. The height prediction corrected for bone age increased over the first 2 years only. Differences in demography and auxology were described according to karyotype and country of origin. A greater height velocity SDS was observed at higher GH doses and when oxandrolone was used concomitantly.

Combined therapy with growth hormone and oxandrolone in adolescent girls with Turner syndrome

Five adolescent girls with Turner syndrome (mean age 13.9 years, mean bone age 12.0 years) were treated with both recombinant human growth hormone (rhGH) and oxandrolone for 2 years with an average increment in height of 13.4 cm. The mean bone age advanced by only 1.2 years, providing an increase in the mean estimated mature height of 9.2 cm. We conclude that rhGH and oxandrolone benefit older teenagers with Turner syndrome because of an increased growth rate with slow progression of skeletal maturation.

Growth hormone (GH) treatment in achondroplasia

Achondroplasia is one of the most commonly known types of skeletal dysplasia in the adult leading to short stature. Before beginning growth hormone (GH) treatment of short stature in patients with achondroplasia, we evaluated their growth pattern and their hypothalamic-pituitary function, including GH secretion. We studied 22 patients with achondroplasia (7 males and 15 females: age range, 3 to 12 years). The z-score of their height at admission was -5.4 +/- 1.2 (mean +/- SD), and that of their annual height gain before admission was -3.1 +/- 1.3 (mean +/- SD). GH response to provocative tests was normal in all patients except five: four showed subnormal (< 10 ng/ml) response to L-Dopa stimuli, and one patient showed subnormal (< 20 ng/ml) response to GRF stimuli. The mean GH concentration during sleep was found to be low (< 5 ng/ml) in three patients. These three patients were suspected to have latent GH deficiency, as they also showed a markedly low IGF-1 level and marked delay of bone age. LH, FSH, TSH, and cortisol response to provocative tests were normal in all the patients. We treated this group of patients with recombinant human GH (1 IU/kg/week). In 18 patients who were treated with GH for more than 6 months, height velocity during GH therapy was significantly increased compared to that before GH therapy (4.1 +/- 0.8 cm/year vs 7.2 +/- 1.4 cm/year). We conclude that parameters reflecting hypothalamic-pituitary function, particularly GH secretion, should be examined in achondroplasia patients, and that GH treatment may be beneficial in the treatment of short stature in achondroplasia.

Does growth hormone treatment of patients with Turner's syndrome cause an abnormal body shape?

The effect of human growth hormone on the body shape of 51 patients with Turner's syndrome (aged 6-19 years) was evaluated. Biosynthetic growth hormone was given in a dose of 24 IU/m2 body surface/week for two years. Karyotype analysis on peripheral blood was performed. Patients older than 12 years also received 0.1 microgram ethinyl oestradiol/kg body weight/day orally. Body shape was characterized by studying pairs of measurements expressed as SD scores (z scores). As reference data, our own locally obtained data from normal children were used. After two years of growth hormone therapy, height, sitting height, bi-acromial and bi-iliac diameter increased from -3.7, -2.9, -1.7 and -1.2 to -1.3, -2.5, -0.6 and +0.5 z scores, respectively. The shape of the patients, expressed as height/bi-iliac diameter and also as sitting height/bi-iliac diameter became more abnormal. As no difference could be noted between the prepubertal and pubertal groups or between the XO and mosaic groups, it is suggested that growth hormone treatment causes a relatively wide pelvis in patients with Turner's syndrome.

Growth hormone treatment in Turner syndrome accelerates growth and skeletal maturation. Dutch Growth Hormone Working Group

Sixteen girls with Turner syndrome (TS) were treated for 4 years with biosynthetic growth hormone (GH). The dosage was 4 IU/m2 body surface s.c. per day over the first 3 years. In the 4th year the dosage was increased to 6 IU/m2 per day in the 6 girls with a poor height increment and in 1 girl oxandrolone was added. Ethinyl oestradiol was added after the age of 13. Mean (SD) growth velocities were 3.4 (0.9), 7.2 (1.7), 5.3 (1.3), 4.3 (2.0) and 3.6 (1.5) cm/year before and in the 1st, 2nd, 3rd and 4th year of treatment. Skeletal maturation advanced faster than usual in Turner patients especially in the younger children. Although the mean height prediction increased by 5.6 cm and 11 of the 16 girls have now exceeded their predicted height, the height of the 4 girls who stopped GH treatment exceeded the predicted adult height by only 0 to 3.4 cm.

Six-year results of a randomized, prospective trial of human growth hormone and oxandrolone in Turner syndrome

Seventy girls with Turner syndrome, verified by karyotype, were randomly assigned to observation or treatment with human growth hormone (hGH), oxandrolone, or a combination of hGH plus oxandrolone for a period of 12 to 24 months, to assess the effect of treatment on growth velocity and adult height. Subsequently, all subjects received either hGH alone or hGH plus oxandrolone. Data are presented for 62 subjects treated for a period of 3 to 6 years. When compared with the anticipated growth rate in untreated patients, the growth rate after treatment with hGH, both alone and in combination with oxandrolone, showed a sustained increase for at least 6 years. Treatment is continuing in over half of the subjects; at present, 14 (82%) of 17 girls receiving hGH alone and 41 (91%) of 45 girls receiving combination therapy exceeded their expected adult heights. Thirty girls have completed treatment; mean height for these 30 patients is 151.9 cm, compared with their mean original projected adult height of 143.8 cm. We conclude that therapy with hGH, alone and in combination with oxandrolone, can result in a sustained increase in growth rate and a significant increase in adult height for most prepubertal girls with Turner syndrome.

Growth hormone secretory status in patients with Turner syndrome

The growth hormone (GH) secretory capacities in patients with Turner syndrome aged 5.1-15.9 years and those with constitutional short stature (CSS) aged 5.2-14.2 years were evaluated by pharmacological and physiological means. The GH response to hypoglycemia in the patients with Turner syndrome was lower than that in the patients with CSS. However, the GH response to arginine was not significantly different between the two patient groups. For the physiological test, the integrated concentration of GH (ICGH), the number of episodic peaks and their mean height were evaluated using blood obtained from the patients every 20 minutes for a period of 24 hours. The ICGH and the mean height of the episodic peaks in the patients with Turner syndrome were significantly lower than those in the CSS patients during the night but not during the day. Negative correlation between the bone age and the night-time values of ICGH was observed in the patients with Turner syndrome. Such correlation was not observed in the CSS patients. The patients with CSS showed a significant day-night difference in the ICGH and the mean height of the episodic peaks, but the patients with Turner syndrome did not show any significant day-night difference in either the ICGH or the mean height of episodic peaks. In conclusion, the GH secretory capacity in patients with Turner syndrome is lower than that in CSS patients.

Growth hormone treatment in Turner's syndrome: short and long-term effects on metabolic parameters

OBJECTIVE

The effect of GH administration on various metabolic parameters and on growth and bone age development was studied in patients with Turner's syndrome.

DESIGN

Patients were treated with daily s.c. GH (20 IU/m2/week) and ethinyloestradiol p.o. (100 ng/kg/day) during the first year and with additional oxandrolone (0.125 mg/kg/day) during the second year. The responses of free fatty acids (FFA), urinary excretion of hydroxyproline (HP) and IGF-I were evaluated after short-term GH application. Glucose tolerance was investigated before any therapy, during treatment with GH and oestradiol and after adding oxandrolone, respectively. The course of growth, bone age and IGF-I levels was followed throughout the study.

PATIENTS

Eleven patients with Turner's syndrome aged 12.6 +/- 1.9 years (mean +/- SD) were included.

RESULTS

Free fatty acids increased significantly 4 hours after one s.c. injection of GH (0.7 +/- 0.2-1.1 +/- 0.3 mmol/l; mean +/- SD). Mean urinary hydroxyproline excretion remained unchanged after 6 weeks of GH therapy (337 +/- 206-299 +/- 145 mumol/m2/24 h), but there was a significant negative correlation between individual hydroxyproline values and the peak serum GH followed stimulation. IGF-I was in the prepubertal range and increased significantly after 3 days of GH injection (30.0 +/- 10.0-42.5 +/- 10.0 nmol/l). Growth velocity (in Turner's syndrome related SD) increased from 0.0 +/- 0.3 SD before treatment to 0.9 +/- 0.8 SD after the first year and to 3.4 +/- 1.3 SD during the second year of treatment. There was no undue acceleration of bone age. During long-term treatment, IGF-I increased significantly only when oxandrolone was added. Two patients had impaired glucose tolerance prior to GH therapy and three additional children developed impaired or abnormal glucose tolerance after GH therapy. Insulin concentrations increased significantly only after introduction of oxandrolone.

CONCLUSIONS

Patients with Turner's syndrome who had lower basal IGF-I levels had significantly higher responses of IGF-I, free fatty acids and hydroxyproline (P less than 0.01 for all parameters) after short-term GH application. The data indicate adequate endocrine and metabolic responses in patients with Turner's syndrome which are the basis for growth promoting action. A considerable number of patients had impaired glucose tolerance during GH treatment.

Growth hormone treatment of Turner syndrome patients with insufficient growth hormone response to pharmacological stimulation tests

Growth before and during treatment with biosynthetic human growth hormone (hGH) was studied in 13 patients with Turner syndrome (TS) and a growth hormone (GH) response of less than 10 micrograms/l to two standard provocative tests. During 1 year of treatment with hGH (0.15 IU/kg per day) height velocity (mean +/- SD) increased significantly (P less than 0.001) from 3.7 +/- 1.8 cm/year to 7.6 +/- 1.5 cm/year. The auxological data in these girls before and during treatment with hGH were similar to those observed in TS patients with a normal response of GH to pharmacological stimuli. It is concluded that in girls with Turner syndrome GH testing should only be performed when height velocity is below the Turner norm. In TS patients with residual growth potential a clinically significant growth acceleration can be obtained with a higher-than-replacement dose of hGH, i.e. 0.15 IU/kg per day, regardless of GH testing.

Two-year results of treatment with methionyl human growth hormone in children with Turner syndrome. Dutch Growth Hormone Working Group

Methionyl growth hormone (somatrem) in a daily dosage of 4 IU/m2 body surface area was administered to 16 girls with Turner syndrome. Low dose ethinyl estradiol (0.1 microgram/kg body weight) was added in girls aged 13 years or more. Mean (SD) height velocity increased from 3.4 (0.9) to 7.2 (1.7) and 5.3 (1.3) cm/year in the first and second year, respectively. Bone age advanced 1.8 years over 2 years and predicted adult height was increased. Apart from the occurrence of anti-GH antibodies there were no side effects. In conclusion, somatrem is an efficacious and safe therapy for short stature in Turner syndrome over a period of 2 years. Longer follow-up is needed before conclusions about its effect on final height can be drawn.