Growth hormone increases rate of pubertal maturation

Increased testicular insulin-like growth factor 1 is associated with gonadal activation by recombinant growth hormone in immature rats

BACKGROUND

In children, recombinant human growth hormone (rhGH) therapy for treatment of short stature has raised concerns of the early onset of puberty. Puberty is initiated by the activation of the hypothalamus-pituitary-gonad axis. Insulin-like growth factor-1 (IGF1) has been known to mediate physiologic effects of GH. To understand the mechanism of precocious sexual maturation following prepubertal GH therapy, the effects of rhGH on the hypothalamus-pituitary-gonad axis were examined in the immature male rats.

METHODS

Immature male rats were given by daily injection of rhGH (1 or 2 IU/kg) from postnatal day (PND) 21 to PND 23 or 30. The effects of rhGH on kisspeptin-GnRH-LH system in the hypothalamus-pituitary axis, systemic and testicular IGF1, spermatogenesis, steroidogenesis, and circulating testosterone levels were examined. The effects of rhGH on the IGF1 expression and steroidogenesis were examined in progenitor LCs in vitro.

RESULTS

Testicular steroidogenic pathway and spermatogenesis marker mRNA levels, number and size of 17β-hydroxysteroid dehydrogenase (+) LCs, and blood testosterone levels of rhGH rats were significantly higher than those of controls on PNDs 24 and 31. Hypothalamic Kiss1 and Gnrh1 mRNA of rhGH rats were significantly higher than those of controls on PND 24, indicating early activation of hypothalamic kisspeptin-GnRH neurons by rhGH. Hypothalamic Igf1 mRNA levels of rhGH rats were significantly higher than those of controls on PND 24 but significantly lower than those of controls on PND 31. Testicular Igf1 mRNA levels were significantly higher in rhGH rats than in the controls on PNDs 24 and 31 whereas circulating IGF1 levels were not. In progenitor LCs, rhGH significantly increased Igf1 and steroidogenic pathway mRNA levels and testosterone production.

CONCLUSIONS

Local increases in testicular IGF1 might be an important mediator of gonadal maturation via activation of LCs steroidogenesis in immature rats given rhGH.

Dwarf mice as models for reproductive ageing research

Dwarf mice are characterized by extremely long lifespan, delayed ovarian ageing, altered metabolism, lower age-related oxidative damage and cancer incidence rate. Snell dwarf, Ames dwarf and growth hormone receptor knockout mice are three commonly used models. Despite studies focusing on ageing and metabolism, the reproductive features of female dwarf mice have also attracted interest over the last decade. Female Snell and Ames dwarf mice have regular oestrous cycles and ovulation rates, as in normal mice, but with a larger ovarian reserve and delayed ovarian ageing. The primordial follicle reserve in dwarf mice is greater than in normal littermates. Anti-Müllerian hormone (AMH) concentration is seven times higher in Ames dwarf mice than in their normal siblings, and ovarian transcriptomic profiling showed distinctive patterns in older Ames dwarf mice, especially enriched in inflammatory and immune response-related pathways. In addition, microRNA profiles also showed distinctive differences in Ames dwarf mice compared with normal control littermates. This review aims to summarize research progress on dwarf mice as models in the reproductive ageing field. Investigations focusing on the mechanisms of their reserved reproductive ability are much needed and are expected to provide additional molecular biological bases for the clinical practice of reproductive medicine in women.

Long-term GH Therapy Does Not Advance Skeletal Maturation in Children and Adolescents

Context

There is no consensus on the effect of recombinant human GH (rhGH) therapy on skeletal maturation in children despite the current practice of annual monitoring of skeletal maturation with bone age in children on rhGH therapy.

Aims

To investigate the effects of long-term rhGH therapy on skeletal age in children and explore the accuracy of bone age-predicted adult height (BAPAH) at different ages based on 13 years of longitudinal data.

Methods

A retrospective longitudinal study of 71 subjects aged 2 to 16 years, mean 9.9 ± 3.8 years, treated with rhGH for nonsyndromic short stature for a duration of 2 to 14 years, mean, 5.5 ± 2.6 years. Subjects with syndromic short stature and systemic illnesses such as renal failure were excluded.

Results

Bone age minus chronological age (BA-CA) did not differ significantly between baseline and the end of rhGH therapy (-1.05 ± 1.42 vs -0.69 ± 1.63, P = 0.09). Piecewise regression, however, showed a quantifiable catch-up phenomenon in BA of 1.5 months per year of rhGH therapy in the first 6.5 years (P = 0.017) that plateaued thereafter (P = 0.88). BAPAH overestimated near-adult height in younger subjects but became more accurate in older subjects (P < 0.0001). IGF-I levels correlated significantly with increases in child's height and BA-CA.

Conclusion

Long-term rhGH therapy demonstrated an initial catch-up phenomenon in skeletal maturation in the first 6.5 years that plateaued thereafter with no overall significant advancement in bone age. These findings are reassuring and support strategic, but not the insurance company mandated reflexive annual monitoring of skeletal maturation with bone age in children receiving rhGH therapy.

Long Term Experience with Growth Hormone Treatment in Children with Chronic Renal Failure

After a decade of experience with recombinant human growth hormone (rhGH) in children with chronic renal failure (CRF), the long-term efficacy and safety of the drug is now established. In prepubertal children, partial catch-up growth is achieved during the first three treatment years, followed by sustained percentile-parallel growth. Discontinuation of rhGH treatment results in catch-down growth in 75% of patients. Treatment efficacy is inversely correlated with age and baseline height velocity, and positively influenced by genetic target height and residual renal function. Skeletal maturation is not accelerated, suggesting a true increase in final height potential. Side effects are limited to a stimulation of insulin secretion, which is not associated with changes in glucose tolerance, and occasional cases of benign intracranial hypertension.

In summary, the advent of rhGH has opened a new era in the management of growth failure in CRF. Available evidence suggests that treatment should start in early childhood and early in the course of renal failure, and should be continued at least until renal transplantation. It remains to be seen whether the beneficial effect of rhGH on height observed during the prepubertal period will result in an eventual increase in adult height.

Why Do Normal Children Have Acromegalic Levels of IGF-I During Puberty?

CONTEXT

The rapid pubertal height growth is unique to humans, but why do we have it? Although the spurt contributes 13% to 15% to the final adult height, we hypothesized that the biological significance of the high acromegalic levels of GH and IGF-I, which are behind the pubertal growth spurt, might primarily occur to stimulate the reproductive organs.

EVIDENCE SYNTHESIS

Animal data have demonstrated that adult Igf1 and Igf2 gene knockout mice that survive show a dramatic reduction in the size of the reproductive organs and are infertile. In humans, case reports of mutations in the genes affecting the GH-IGF axis and growth (GH, GHRH, GH-R, STAT5b, IGF-I, IGF-II, IGF-1R, PAPPA2) are also characterized by delayed pubertal onset and micropenis. Furthermore, GH treatment will tend to normalize the penile size in patients with GH deficiency. Thus, the endocrine effects of high IGF-I levels might be needed for the transition of the sexual organs, including the secondary sex characteristics, from the "dormant" stages of childhood into fully functioning reproductive systems. The peak IGF-I levels, on average, occur 2 years after the peak height growth velocity, suggesting reasons other than longitudinal growth for the high IGF-I levels, and remain high in the years after the height spurt, when the reproductive systems become fully functional.

CONCLUSION

We suggest that the serum levels of IGF-I should be monitored in children with poor development of sexual organs, although it remains to be investigated whether GH should be added to sex steroids in the management of hypogonadism for some pubertal children (e.g., boys with micropenis).

Adult and near-adult height in patients with severe insulin-like growth factor-I deficiency after long-term therapy with recombinant human insulin-like growth factor-I

BACKGROUND

Treatment with recombinant human insulin-like growth factor-I (IGF-I) stimulates linear growth in children with severe IGF-I deficiency (IGFD).

AIMS

To evaluate the efficacy and safety of treatment with IGF-I in patients with severe IGFD treated until adult or near-adult height.

METHODS

Twenty-one children with severe IGFD were treated until adult or near-adult height under a predominantly open-label design. All patients were naive to IGF-I. Recombinant human IGF-I was administered subcutaneously in doses between 60 and 120 µg/kg twice daily. Nine patients received additional therapy with gonadotropin- releasing hormone (GnRH) analog for a mean period of 2.9 ± 1.8 years.

RESULTS

Mean duration of treatment was 10.0 years. Mean height velocity increased from 3.1 cm/year prior to treatment to 7.4 cm/year during the first year of treatment. Height velocities during the subsequent years were lower, but remained above baseline for up to 12 years. Cumulative mean Δ height SD score at (near) adult height was +2. The observed mean gain in height was 13.4 cm more than had been expected without treatment. The adult height achieved by the patients also treated with GnRH analog was not different from those who received IGF-I therapy alone. There were no new safety signals identified in these patients, a subset of those previously reported.

CONCLUSION

Long-term therapy with IGF-I improves adult height of patients with severe IGFD. Most patients did not bring their heights into the normal adult range.

The effects of recombinant human growth hormone on linear growth in children with Crohn's disease and short stature

BACKGROUND/AIMS

The efficacy of recombinant human growth hormone (rhGH) in treating the growth failure associated with Crohn's disease (CD) is unclear.

METHODS

Retrospective data analysis at 12 months before (T-12), 6 months before (T-6), at baseline (T+0), 6 months after (T+6) and 12 months after (T+12) rhGH treatment in seven patients with CD (five males).

RESULTS

Median chronological age (CA) and median difference between CA and bone age was 15.9 yr (range, 13.0 to 17.9) and 1.7 yr (-0.7 to 3.3), respectively. Median dose of rhGH at T+0 was 0.23 mg/wk (0.15 to 0.31). Pubertal status remained unchanged in 6/7 patients. Median albumin and C-reactive protein (CRP) were similar at T+0 and T+6. Median height SDS at T+0, T+6 and T+12 was -2.2 (-4.0 to -1.5), -1.9 (-4.1 to -0.8), -1.9 (-4.1 to -0.7), respectively (NS). Median height velocity (HV) SDS at T+0 and T+6 was -2.5 (-4.8 to 1.4) and -0.9 (-5.3 to 3.4), respectively (NS). There was a positive correlation between percentage change in HV SDS at T+6 and dose of rhGH at T+0 (r = 0.8, p = 0.03).

CONCLUSION

Introduction of rhGH therapy was associated with a cessation in the deterioration in linear growth. However, an improvement in height SDS was not observed over the period of the study. Future studies should explore the efficacy of a higher dose of rhGH in CD.

Ovulation induction in a poor responder with panhypopituitarism: a case report and review of the literature

BACKGROUND

Most women with panhypopituitarism will undergo successful ovulation induction with gonadotropin therapy. Few proven treatment options exist for those who respond poorly to such therapy. A poor response may indicate diminished ovarian reserve, or reflect a deficiency of other key components for ovarian function.

CASE

A 31-year-old female with panhypopituitarism and a poor response to gonadotropin therapy took growth hormone (GH) replacement for 4 months prior to restarting gonadotropins. When the serum level of insulin-like growth factor-I normalized, she began ovulation induction with gonadotropins with transdermal estradiol. After 63 days of gonadotropin therapy, she had a leading follicle of 18 mm, followed by follicles of 16.5 mm and 15.5 mm. The serum estradiol was 796 pg/ml, and human chorionic gonadotropin was administered. The patient conceived with timed intercourse. A prior attempt at ovulation induction with gonadotropins alone failed to produce follicular development.

CONCLUSION

Prolonged gonadotropin treatment may be necessary to achieve ovulation and avoid the misdiagnosis of ovarian failure. Co-treatment with GH and estrogen may improve the follicular response in a poor responder with panhypopituitarism.

Growth hormone normalizes pubertal onset in children with cystic fibrosis

Children with cystic fibrosis (CF) have a high incidence of delayed puberty and poor growth. We retrospectively reviewed pubertal maturation data from 105 children with CF who had participated in studies on growth hormone (GH). As part of the GH study, participants were randomized into two cohorts, one of which was treated with GH for 1 year, and then followed off GH, and the other group was first followed off GH, and then treated with GH for 1 year. Pubertal staging was obtained throughout these studies and we have retrospectively analyzed the data.

RESULTS

In prepubertal females, GH treatment resulted in a normalized onset of breast development as compared to delayed onset in non-treated females. Females treated during puberty had a normal tempo of breast development. In prepubertal males, GH treatment resulted in a normalized onset of testicular volume compared to non-treated males. Testicular size progression was not accelerated in pubertal boys treated with GH.

CONCLUSION

GH treatment normalizes pubertal onset in prepubertal children with CF.

Final height in a patient with Laron syndrome after long-term therapy with rhlGF-I and short-term therapy with LHRH-analogue and oxandrolone during puberty

OBJECTIVE

To report our experience on long-term treatment with recombinant-human-IGF-I (rhIGF-I) of a female patient with Laron syndrome (mutation G223G in the GH receptor gene), who received short-term treatment (1 yr) with LHRH analogue at the start of puberty and subsequently with oxandrolone.

CASE REPORT

The patient started IGF-I therapy (dose 40 microg/kg bid for 9 months, 80 microg/kg bid until 13.7 yr of age and 120 microg/kg bid thereafter) when she was 7.6 yr old (height -6 sds), and was treated for 9.4 yr until final height (cm 129.7; -5.5 sds). At first signs of puberty (age 12.7 yr; height 116.3; -5.3 sds), LHRH analogue was started (3.75 mg/28 days) and bone age progressed by 6 months in the 12-month period. Growth velocity decreased in the 6-12th month of combined treatment (0.9 cm/6 months), and treatment was suspended. At age 14.8 (height 124.5; -6.6 sds), oxandrolone was added (0.1 mg/kg/day), but after 12 months (height 128 cm; -5.7 sds) bone age increased from 11.5 to 13.5 yr and the drug was stopped. No side effects occurred during the various treatments. Body segments progressed harmonically: there was a tendency towards improvement in the upper to lower body segment ratio and in cranial growth. Only biiliac diameter did not increase during LHRH treatment. During the 9-yr period, body mass index (BMI), subscapular and triceps skinfold centiles did not show any significant variations.

CONCLUSIONS

Our patient with Laron syndrome after long-term treatment showed a final result below the initial expectations, confirming that IGF-I used with the present schedule is less effective than GH in GH-deficient patients. LHRH analogue therapy at puberty was associated with a slower bone age maturation but with an almost complete arrest of growth. On the contrary, oxandrolone sustained growth but caused an excessive maturation of bone age. Other strategies are necessary to improve final height in these patients.

Peripheral patterns of growth hormone, luteinizing hormone, and progesterone before, at, and after puberty in buffalo heifer

Buffalo, the premier dairy animal in India, suffers from slow growth rate, delayed puberty, and silent heat. It is not known whether the delay in puberty in such animals is due to the delay in expression of hypothalamus-pituitary-gonadal functions. To determine the changes in growth hormone (GH), luteinizing hormone (LH), and progesterone before, at, and after puberty of Murrah buffalo heifers, six Murrah buffalo heifers (21.92 +/- 1.09 months of age, 269.67 +/- 7.97 kg body weight) were assigned to well-ventilated individual pens and fed a roughage-concentrate diet to provide weight gain of 0.4 kg/day. Blood samples were collected at 3-day intervals during a period of 12 months, and plasma harvested from blood samples was assayed for progesterone, LH, and GH. The day that plasma progesterone was greater than 1 ng/mL for three consecutive sampling days was defined as the day of puberty. Heifers attained puberty at an average age of 31.53 +/- 0.88 months with a body weight of 380.67 +/- 6.42 kg. Progesterone levels were very low (0.20 to 0.30 ng/mL) during the pre-pubertal period. There were two distinct elevations before the day of puberty onset. Plasma LH and GH concentrations increased (P < 0.05) during the months preceding puberty and were highest during the month before puberty. GH and LH were positively correlated (P < 0.05) prior to (r = +0.59) as well as after puberty (r = +0.42). A positive correlation (P < 0.05)between LH and body weight during the pre-pubertal period (r = +0.61) and thereafter, negative correlation (P < 0.05) during post-pubertal period (r = -0.64) was noted. GH and body weight showed positive correlation both before puberty (r = +0.92, P < 0.01) and after puberty (r = +0.32, P < 0.05). Results suggest that both GH and LH are equally important and vital cues in inducing onset of ovarian functions in buffalo heifers.

Uterus size and ovarian morphology in women with isolated growth hormone deficiency, hypogonadotrophic hypogonadism and hypopituitarism

OBJECTIVE AND SUBJECTS

Current data suggest a permissive role for the somatotrophic axis in the reproductive process, mainly by affecting the onset of puberty and the maintenance of regular menstrual cyclicity. To assess a possible interface between GH and reproductive axes in determining the uterus size, we retrospectively evaluated 58 pelvic ultrasound scans in adult women with either isolated growth hormone deficiency (GHD; n = 12), hypogonadotrophic hypogonadism (HH; n = 24) or hypopituitarism (HP; n = 22) of prepubertal onset. Pelvic ultrasound was performed before oestrogen replacement in patients with HH or HP, and after completion of GH treatment in the majority of patients with HP. Eight women with HH and seven with HP had a second pelvic ultrasound examination after being established on oestrogen replacement therapy. A group of 19 young healthy women with no previous history of pregnancy or miscarriage were included for comparison of ultrasound data.

RESULTS

Uterine measurements, length and uterine cross-sectional area (UXA) were significantly less in the three study groups compared to healthy controls [median UXA: GHD 18.0 cm(2) (range 9.9-28.6 cm(2)), HH 7.0 cm(2) (range 1.3-18.5 cm(2)), HP 11.8 cm(2) (range 1.6-21.8 cm(2)) and controls 23.0 cm(2) (range 16.1-31.7 cm(2)); P < 0.001]. The median age of oestrogen replacement was significantly later in HH [19 years (range 16-26 years)] compared to HP [16.5 years (range 13-20 years)]P = 0.03, while the median age of menarche of GHD patients was 14.5 years (range 11-16 years), which was not statistically different from controls [13.0 years (range 12.5-14.5 years)]. Repeat uterine measurements on oestrogen in the subgroup of 15 patients did not reach the normal values [pretreatment UXA: 4.2 cm(2) (range 1.6-16.1 cm(2)), post-treatment UXA: 12.6 cm(2) (range 4-23 cm(2))]. Ovarian volume was smaller in the two groups of women with gonadotrophin deficiency (HH and HP), while a polycystic ovarian morphology was notably more prevalent in the two groups who had received GH treatment being found in 75 and 58% of women with GHD and HP, respectively, compared with 12.5% in women with HH (P < 0.004).

CONCLUSIONS

Our findings suggest that GHD might have an independent effect in determining uterus size and therefore the consequences of GHD plus oestrogen deficiency on uterus growth might be additive. The fact that uterine measurements between HH and HP patients did not differed significantly in this study may be explained by the fact that oestrogen replacement has been substituted earlier in the latter group. Furthermore, it appears that standard oestrogen replacement therapy did not result in normal uterine growth. A polycystic ovarian morphology may be a consequence of GH treatment.

Reduced Growth Hormone Secretion Prolongs Puberty But Does Not Delay the Developmental Increase in Luteinizing Hormone in the Absence of Gonadal Negative Feedback1

Previous studies have shown that the growth hormone (GH) axis is important for timing the later stages of puberty in female monkeys. However, it is not clear whether these growth-related signals are important for the initiation of puberty and early pubertal events. The present study, using female rhesus monkeys, used two approaches to answer this question. Experiment 1 tested the hypothesis that reduced GH secretion would blunt the rise in nocturnal LH secretion in young (17 mo; n = 7) but not older adolescent ovariectomized females (29 mo; n = 6). Reduced GH secretion was induced by treating females with the sustained release somatostatin analogue formulation, Sandostatin LAR (625 microg/kg). Morning (0900-0930 h) and evening (2200-2230 h) concentrations of bioactive LH were higher in older adolescent compared to young adolescent females. However, diurnal concentrations were not affected by the inhibition of GH secretion in either age group when compared to the placebo-treated, control condition. Experiment 2 tested the hypothesis that reduced GH secretion induced in young juvenile females would delay the initial increase in nocturnal LH secretion and subsequent early signs of puberty. In order to examine this hypothesis, puberty in control females (n = 7) was compared to those in which puberty had been experimentally arrested until a late adolescent age (29 mo) by the use of a depot GnRH analogue, Lupron (750 microg kg(-1) mo(-1); n = 7). Once the analogue treatment was discontinued, the progression of puberty was compared to a group treated in a similar fashion but made GH deficient by continuous treatment with Sandostatin LAR (n = 6). Puberty occurred as expected in control females with the initial rise in evening LH at 21 mo, menarche at 22 mo, and first ovulation at 30 mo. As expected, Lupron arrested reproductive maturation, but elevations in morning and evening LH and menarche occurred within 2 mo of the cessation of Lupron in both Lupron and Lupron-GH-suppressed females. In contrast, first ovulation was delayed significantly in the Lupron-GH-suppressed females (41 mo) compared to the Lupron-only females (36 mo). These data indicate that within this experimental model, reduced GH secretion does not perturb the early stages of puberty but supports previous observations that the GH axis is important for timing the later stages of puberty and attainment of fertility. Taken together, the data indicate that factors that reduce GH secretion may have a deleterious effect on the completion of puberty.

Phenotypic analysis and growth response to different growth hormone treatment schedules in two siblings with an inactivating mutation in the growth hormone-releasing hormone receptor gene

Mutations in the GHRH receptor (GHRHR) gene (GHRHR) are emerging as a common cause of familial isolated growth hormone deficiency (IGHD) type IB. The use of gonadotropin-releasing hormone (GnRH) analogues has been advocated as a tool to delay puberty in patients with isolated GH deficiency (IGHD), allowing longer time for the beneficial effect of exogenous human GH (hGH) treatment on growth. We describe two male siblings with IGHD due to a homozygous missense GHRHR mutation who, because they were started on hGH therapy at different ages, presented with different height SDS at the onset of puberty and therefore had different predicted target heights. The shorter brother was treated with GnRH analogue plus hGH for 3 years, whereas the other brother received only hGH. Despite different predicted heights at the onset of puberty, they attained similar final heights. We conclude that in patients with IGHD, GnRH analogue treatment should be considered to delay puberty and obtain a maximal growth response if hGH treatment is started in late childhood and the predicted height at puberty onset is below the genetic target.

Sex steroid replacement during and after the induction of puberty

The main aim of sex steroid replacement during induction of puberty is to obtain a balance between healthy psychological and somatic development and optimal final height and peak bone mass (PBM). At present, the age at which it is considered appropriate to begin inducing puberty is younger than it was in the past. This trend aims for optimisation of prepubertal and pubertal growth through earlier onset of growth hormone (GH) therapy and administration of higher doses during puberty as necessary. Adequate initiation of puberty should ensure not only optimal final height and psychological balance, but also normal body proportions, appropriate bone formation and preservation of fertility for children with GH and gonadotropin deficiencies.

Pelvic ultrasound evaluation in patients with Turner syndrome during treatment with growth hormone

OBJECTIVES

Treatment with growth hormone (GH), alone or in combination with oxandrolone, is used in patients affected by Turner syndrome to improve growth velocity and adult height. Since GH interacts with gonadotropins in the stimulation of the human ovary, the aim of our study was to evaluate the possible effects of GH administration on uterine and ovarian characteristics.

METHODS

We performed pelvic ultrasound assessment in 29 patients with Turner syndrome aged 7.5-16.6 years (19 with 45,X karyotype; 10 with variant karyotypes) before and during treatment with GH alone. Uterine volume and ovarian size and morphology were compared to those of 23 age-matched girls with Turner syndrome not treated with GH. Both patients and controls were divided into prepubertal and pubertal groups. Cross-sectional and longitudinal studies (before and every 6 months during GH treatment for 2 years) were performed.

RESULTS

We observed a significantly higher uterine anteroposterior diameter and volume in younger (< or = 11 years) GH-treated Turner syndrome girls than in those who were untreated. Also visualization and heterogeneous echopattern of the ovaries were significantly more frequent in treated than in untreated Turner syndrome patients, particularly before the age of 11 years. The longitudinal study showed a significant increase in uterine volume, more related to treatment than to age. Spontaneous breast development and menarche were found more frequently in GH-treated Turner syndrome girls.

CONCLUSION

Growth hormone therapy can have a co-gonadotropin role in patients with Turner syndrome.

Growth hormone-related effects on apoptosis, mitosis, and expression of connexin 43 in bovine in vitro maturation cumulus-oocyte complexes

Pituitary LH and FSH are known to be the major regulators of ovarian function. In the last few years, however, there has been evidence that growth hormone (GH) is also involved in ovarian regulation. Therefore, the aim of our study was to elucidate the mechanisms of GH action during in vitro maturation (IVM) of bovine cumulus-oocyte complexes (COCs). As shown by detection of the nuclear cell proliferation-associated antigen Ki-67, COCs matured in vitro in the presence of GH revealed a significantly (P < 0.05) higher proportion of proliferating cumulus cells (12.6%) compared with the COCs matured in the control medium TCM 199 (9.9%). In contrast, the percentage of proliferating cells was not increased by supplementation of the medium with a combination of GH and insulin-like-growth factor I (IGF-I). Apoptosis as determined by TUNEL (terminal doxynucleotidyl transferase mediated dUTP nick-end labeling) was significantly (P < 0.05) reduced in the cumulus cells by GH treatment. COCs matured with a combination of GH and IGF-I revealed the lowest percentage of apoptotic cells (11%). The localization and quantification of the gap junction protein connexin 43 (Cx 43) demonstrated that GH induced a significant decrease in the synthesis of the Cx 43 protein in the cumulus cells. Our results imply that GH increases cumulus expansion by promotion of cell proliferation and inhibition of apoptosis. Whereas the increase in cell proliferation is a direct effect of GH, the antiapoptotic effects of GH during in vitro maturation are modulated by IGF-I. Stimulatory effects of GH on oocyte maturation are correlated with changes in the synthesis of gap junction proteins.

Impact of growth hormone resistance on female reproductive function: new insights from growth hormone receptor knockout mice

We examined multiple aspects of reproductive function in growth hormone receptor gene knockout (GHR-KO) and normal mice to clarify the role of growth hormone in female reproduction. In adult animals, estrous cycle duration was comparable in all mice housed individually but was significantly longer in group-housed GHR-KO females. Histological evaluation of ovaries of adult females at estrus showed that the numbers of preovulatory follicles and corpora lutea were significantly reduced in GHR-KO mice, as was the plasma estradiol level. The number of atretic preovulatory follicles was reduced in GHR gene-ablated animals. Although reverse transcription polymerase chain reaction analysis revealed reduced ovarian insulin-like growth factor I (IGF-I) mRNA expression in GHR-KO females, the expression of several steroidogenic enzyme mRNAs did not differ between groups. The numbers of active corpora lutea and uterine implantation sites were reduced in GHR-KO females at Day 7 of gestation. When young females were mated to normal males, latency to first mating and age of the female at first mating were significantly delayed in GHR-KO females, but maternal age at first conception was similar between groups. Significantly fewer virgin GHR-KO females exhibited pseudopregnancies when initially placed with vasectomized normal males than did normal female counterparts. Growth hormone resistance and IGF-I insufficiency negatively impacted 1) follicular development/ovulation rate, 2) sexual maturation, 3) production of and responsiveness to pheromonal signals, and 4) the ability of virgin females to respond to coitus by activation of luteal function. Although GHR-KO female mice are fertile, they exhibit quantitative deficits in various parameters of reproductive function.

Effects of growth hormone on testicular dysfunction induced by cyclophosphamide (CP) in GH-deficient rats

Growth hormone (GH) is known to accelerate spermatogenesis and maintain gonadal function. In this study, we evaluated the effect of GH on recovery from testicular damage induced by cyclophosphamide (CP). Eleven- to fourteen-week-old GH-deficient Lewis rats (dw/dw) were divided into 4 groups (n = 10 each), with one group serving as controls. In the CP group, CP was intravenously administered in daily doses of 50 mg/kg for 2 days, followed by daily doses of 10 mg/kg for the next 3 days. In the GH group, rat GH was subcutaneously administered at a daily dose of 0.3 mg/kg until the rats were sacrificed. In the CP/GH group, GH and CP administration were started simultaneously. In the CP/preGH group, GH administration was started 14 days before CP administration. Five rats from each group were sacrificed at days 14 and 28 after administration of CP. Spermatogenesis was then evaluated morphometrically by counting numbers of cells at several stages of the spermatogenic cycle. On day 14, there were no significant differences in the numbers of the spermatocytes between CP and CP/GH group. On day 28, the numbers of spermatocytes and motility of spermatozoa in CP/GH group were greater than those of CP group were. In the CP/preGH group, these effects of GH administration were not observed. These results suggested that administration of GH improved testicular function damaged by CP under GH-deficient condition, when GH and CP administration are started simultaneously.

Growth hormone releasing hormone test for infertile men with spermatogenetic maturation arrest

PURPOSE

Growth hormone has an important role in the function of the male reproductive system. We investigated infertile men with impaired growth hormone secretion.

MATERIALS AND METHODS

Growth hormone status was studied in 8 fertile men and 9 infertile men with azoospermia due to spermatogenetic maturation arrest. Growth hormone releasing hormone, the specific stimulatory neurohormone, was used in the growth hormone stimulation test. A dose of 100 microg. of growth hormone releasing hormone was infused intravenously and serum growth hormone concentrations were measured at 0, 15, 30, 60, 90 and 120 minutes. Serum follicle-stimulating hormone, luteinizing hormone, prolactin, testosterone and estradiol were also measured before the test.

RESULTS

Serum follicle-stimulating hormone concentrations were significantly increased in the azoospermic group and basal levels of growth hormone were similar to those in the control group. Serum growth hormone concentrations increased after injection of growth hormone releasing hormone and the levels of growth hormone peaked after 30 minutes in both groups. At time 30 minutes growth hormone levels had decreased significantly more in the azoospermic group than in the controls. Men with azoospermia due to spermatogenetic maturation arrest had a low response to the growth hormone releasing hormone test.

CONCLUSIONS

Relative growth hormone insufficiency, which may be caused by reduced reactivity to growth hormone releasing hormone in pituitary growth hormone secretory cells, is strongly related to spermatogenic dysfunction.

Growth hormone and sex steroids. Interactions in puberty

Dynamic interactions among growth hormone, IGF-1, and sex steroidal hormones have a major role in the achievement of full height potential and the body composition changes in adolescence. Testosterone and estrogen affect the growth hormone neuroendocrine rhythms, and growth hormone, in turn, potentiates many of the metabolic actions of the sex steroids. Leptin is also thought to have a key regulatory role in the process of sexual development in the child, but the precise nature of these interactions is unclear. The targeted replacement of hormonal deficiencies in puberty and manipulation of the timing of pubertal maturation have resulted in better strategies to treat profoundly short children during this period; however, more research is needed to determine the consequences of such approaches in aspects of metabolism other than linear growth.

Effect of growth hormone treatment on testicular function, puberty, and adrenarche in boys with non-growth hormone-deficient short stature: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To evaluate the effect of growth hormone (GH) therapy on pubertal onset, pubertal pace, adult testicular function, and adrenarche in boys with non-GH-deficient short stature.

STUDY DESIGN

Randomized, double-blind, placebo-controlled trial. GH (0.074 mg/kg, subcutaneously, 3 times per week) or placebo treatment was initiated in prepubertal or early pubertal boys and continued until near final height was reached (n = 49). Statistical significance was assessed by survival analysis, repeated-measures analysis of variance, and Student t test.

RESULTS

GH therapy did not affect the age at pubertal onset, defined either by testicular volume >4 mL or by testosterone concentration >1.0 nmol/L (30 ng/dL). GH treatment also did not affect the pace of puberty, defined either by the rate of change in testicular volume or testosterone concentration during the 4 years after pubertal onset. In boys followed up to age > or =16 years during the study, there were no significant differences in final testicular volume or in plasma testosterone, luteinizing hormone, or follicle-stimulating hormone concentrations. The pace of adrenarche, assessed by change in dehydroepiandrosterone sulfate levels over time, also did not differ significantly between the GH and placebo groups.

CONCLUSION

Our findings suggest that GH treatment does not cause testicular damage, alter the onset or pace of puberty, or alter the pace of adrenarche in boys with non-GH-deficient short stature.

Growth hormone: roles in male reproduction

Growth hormone (GH), as its name suggests, is obligatory for growth and development. It is, however, also required for sexual differentiation and pubertal maturation and participates in gonadal steroidogenesis and gametogenesis. These roles are likely to reflect the endocrine actions of pituitary GH, directly at gonadal sites and indirectly via hepatic insulin-like growth factor-1. However, because GH is also produced in gonadal tissues, it may act in paracrine or autocrine ways to regulate local processes that are strategically regulated by pituitary GH. The concept that GH is a major regulator of male reproduction is the focus of this review.

Effect of growth hormone treatment on the adult height of children with chronic renal failure. German Study Group for Growth Hormone Treatment in Chronic Renal Failure

BACKGROUND

Growth hormone treatment stimulates growth in short children with chronic renal failure. However, the extent to which this therapy increases final adult height is not known.

METHODS

We followed 38 initially prepubertal children with chronic renal failure treated with growth hormone for a mean of 5.3 years until they reached their final adult height. The mean (+/-SD) age at the start of treatment was 10.4+/-2.2 years, the mean bone age was 7.1+/-2.3 years, and the mean height was 3.1+/-1.2 SD below normal. Fifty matched children with chronic renal failure who were not treated with growth hormone served as controls.

RESULTS

The children treated with growth hormone had sustained catch-up growth, whereas the control children had progressive growth failure. The mean final height of the growth hormone-treated children was 165 cm for boys and 156 cm for girls. The mean final adult height of the growth hormone-treated children was 1.6+/-1.2 SD below normal, which was 1.4 SD above their standardized height at base line (P< 0.001). In contrast, the final height of the untreated children (2.1+/-1.2 SD below normal) was 0.6 SD below their standardized height at base line (P<0.001). Although prepubertal bone maturation was accelerated in growth hormone-treated children, treatment was not associated with a shortening of the pubertal growth spurt. The total height gain was positively associated with the initial target-height deficit and the duration of growth hormone therapy and was negatively associated with the percentage of the observation period spent receiving dialysis treatment.

CONCLUSIONS

Long-term growth hormone treatment of children with chronic renal failure induces persistent catch-up growth, and the majority of patients achieve normal adult height.

Is there a place for combined therapy with GnRH agonist plus growth hormone in improving final height in short statured children?

The availability of recombinant human growth hormone (GH) and the optimization of substitutive therapy have improved final growth in children with GH deficiency, but despite this some of them fail to grow to their genetic potential. In particular, this may occur in patients who started the substitutive therapy too late and/or in whom bone age progressed too fast during GH administration. In these patients, with unfavorable auxological characteristics, the administration of a GnRH agonist in combination with GH may slow down bone maturation and prolong prepubertal growth, mimicking, to some extent, the growth pattern of patients with GH + Gn deficiency who grow better than children with isolated GHD. A different condition in which such a combined therapy might be used is the short normal child. As they are short but normally-growing children, the onset of puberty is in general appropriate for their chronological age but precocious for their height age. Thus, slowing down pubertal maturation may increase the time available for growth. GH would sustain growth during both GnRHa administration and after its withdrawal, when puberty starts again. Our preliminary results suggest that the administration of GH + GnRHa in combination may have a positive effect on final height in selected children with isolated GHD and in short normal children.

Quantitative growth hormone secretion and final adult height

OBJECTIVE

The relationship of quantitative GH secretion to height, growth velocity and puberty is complex and has been the subject of extensive study in children. This study was designed to relate quantitative GH secretion to final height.

SUBJECTS

Twenty tall (> 183 cm, 90th centile for adult height) and 20 short (< 166 cm, 10th centile) postpubertal men who had recently completed linear growth (age range 18-27 years).

MEASUREMENTS

GH dynamics were studied on four occasions; insulin (0.15 units/kg, iv)-induced hypoglycaemia and GHRH (100 mg, iv) with and without the anticholinesterase, pyridostigmine (120 mg orally). Spontaneous nocturnal GH secretion was assessed by 20 minute sampling from 2100 h until 0600 h. GH was measured by IRMA. Analysis was by comparison of peak GH response and area under the curve (AUC). GH profiles were further analysed using the 'pulsar' programme.

RESULTS

The mean height in the tall group was 187.7 cm (range 183-197) compared to 163.5 cm (range 160-166) for the short group. No difference existed between groups in the GH response to hypoglycaemia or GHRH with and without pyridostigmine. Area under the curve, pulse number, length and amplitude for spontaneous nocturnal GH secretion showed no significant difference between the tall and short subjects. Serum IGF-I (mean 230.5 +/- 15. 4 vs. 230.6 +/- 18.9 microg/l) did not differ between the groups.

CONCLUSIONS

Quantitative GH secretion does not appear to be an important determinant of final height in healthy individuals.

GH substitution does not alter the pulsatile pattern of LH in amenorrhoeic growth hormone deficient women

OBJECTIVE

GH substitution in GH-deficient (GHD) children promotes pubertal development. In some GHD women, secondary amenorrhoea occurs after discontinuation of GH treatment. This study was designed to investigate whether GH substitution directly influences the GnRH pulse generator. For this reason, the pulsatile release of LH was studied in amenorrhoeic GHD women before and during GH substitution.

DESIGN

GH deficiency was confirmed by an insulin tolerance test. During a 24-h period, blood samples were drawn every 10 min for determination of LH, FSH and GH levels. Oestradiol and IGF-1 were determined at 1000 h and 2200 h. After the first test day, patients started with GH substitution, 0.25 IU/kg/week. During month 6 of GH treatment, the 24 h blood sampling was repeated.

SUBJECTS

Ten amenorrhoeic GH-deficient women participated in the trial. All were diagnosed as GH deficient during childhood or adolescence. Eight of them had been treated with GH during childhood. Seven women suffered from primary amenorrhoea and three from secondary amenorrhoea. Six women were started with GH substitution after the first test day (according to randomization in a larger study).

MEASUREMENTS

LH and GH were determined every 10 min and FSH every 60 min. LH pulse detection was conducted using a validated statistical method.

RESULTS

Prior to GH treatment, the LH pulse interval did not show a diurnal pattern as found during normal pubertal development. During GH treatment, IGF-1 levels rose significantly. No differences were found in mean LH, LH pulse amplitude and LH pulse interval before and during GH treatment. Oestradiol levels did not change either.

CONCLUSIONS

GH substitution in amenorrhoeic GH-deficient women does not alter the pulsatile pattern of LH. This may suggest that GH treatment does not influence central nervous system control of gonadotropin secretion in GHD patients.

Randomised controlled trial of recombinant human growth hormone in prepubertal and pubertal renal transplant recipients. British Association for Pediatric Nephrology

AIMS

To evaluate the efficacy (height velocity (HV), change in height standard deviation score (delta HSDS)), and safety (glomerular filtration rate (GFR), incidence of rejection, and calcium and glucose metabolism) of recombinant human growth hormone (rhGH) treatment after renal transplantation.

DESIGN

A two year randomised controlled trial.

SUBJECTS

Fifteen prepubertal and seven pubertal children: mean (SD) age, 13.0 (2.6) and 15.2 (2.4) years, respectively; mean (SD) GFR, 51 (30) and 48 (17) ml/min/1.73 m2, respectively. Six prepubertal and three pubertal children were controls during the first year; all received rhGH in the second year.

RESULTS

In the first year, mean (SE) HV and delta HSDS in the prepubertal treated group increased compared with controls: 8.1 (0.9) v 3.7 (0.6) cm/year and 0.6 (0.1) v -0.3 (0.2), respectively. In the pubertal treated group, mean (SE) HV and delta HSDS were also greater: 10.1 (0.6) v 3.9 (1.3) cm/year and 0.6 (0.1) v -0.1 (0.2), respectively. Comparing all treated and control children, there was no significant change in GFR: treated group, mean (SE) 9.9 (5.4) ml/min/1.73 m2 v control group, -1.6 (7.6) ml/min/1.73 m2. There were also no differences in the incidence of rejection in the first year: eight episodes in 13 patients v five episodes in nine patients, respectively. Phosphate, alkaline phosphatase (ALP), parathyroid hormone (PTH), and fasting insulin concentrations rose during the first year of treatment, but not thereafter. In the second year of treatment, HV remained above baseline.

CONCLUSION

Treatment with rhGH improves growth in prepubertal and pubertal children with renal transplants, with no significant change in GFR or the incidence of rejection. Phosphate, ALP, PTH, and insulin increased during the first year of treatment.

Developmental changes in the expression of the growth hormone receptor messenger ribonucleic acid and protein in the bovine ovary

By reverse transcription-polymerase chain reaction, the transcript of the growth hormone receptor (GHR) was demonstrated in oocytes, follicular cells, and corpus luteum of the bovine ovary. Immunoblotting using the monoclonal antibody mAb 263 resulted in a distinct protein band at 120 kDa, confirming that translation of the mRNA takes place in the same cells. Nonradioactive in situ hybridization revealed that distribution of the mRNA encoding GHR was correlated with the developmental stage of the follicle. Whereas in primordial and primary follicles the oocyte showed distinct amounts of the transcript encoding GHR, in tertiary follicles the mRNA was predominantly localized in the cells of the cumulus oophorus. GHR mRNA was also expressed in the large granulosa lutein cells, in the germinal epithelium, and in the endothelial cells of ovarian vessels. Colocalization of the GHR protein showed a distribution pattern identical to that of the mRNA. In calves, oocyte and follicle cells changed GHR expression in the same way as in the adult ovary. During embryonic development of the ovary, distinct amounts of the mRNA encoding GHR were found in primordial follicles shortly before birth. Our results imply that the GHR is involved in ovarian ontogenesis, especially in early folliculogenesis.

Unchanged testosterone production rates in growth hormone-treated healthy men

The effect of biosynthetic human GH on the production rates of testosterone was determined in healthy men (n = 7) using the stable isotope dilution technique and mass spectrometry. 1Alpha,2alpha-d-testosterone (20 microg/h) was infused for 10 h (0800-1800 h). Blood samples obtained at 20-min intervals from 1400-1800 h were pooled during two 2-h periods. Subsequently, each volunteer received a daily dose of biosynthetic human GH (4 IU/day sc) for 7 days. This resulted in a rise in plasma concentrations of somatomedin-C from, basal, 0.67+/-0.13 U/mL to 1.20+/-0.2 U/mL on day 7 (P < 0.0001). Testosterone production rates (basal: 209.9+/-31.0 microg/h) were unchanged by treatment with GH (day 7: 192.2+/-30.1 microg/h). In healthy men, short-term treatment with sc GH does not influence endogenous testosterone production rates.

Growth hormone and ovarian function

Growth and reproductive development are closely co-ordinated during puberty but there is also evidence that growth hormone (GH) may have a physiological role in adult ovarian function. Both GH and the insulin-like growth factors (IGFs) have been shown to augment granulosa cell proliferation and steroidogenesis in the human Graafian follicle, suggesting that GH may act as a 'co-gonadotrophin' at ovarian level. Furthermore, the intra-ovarian 'IGF system' (i.e. IGFs and IGF-binding proteins) may be implicated in folicular atresia and in disorders of follicular function associated with polycystic ovary syndrome (PCOS). The clinical importance of GH to ovarian function in the adult is illustrated by the finding that adjuvant GH treatment reduces the dose of exogenous gonadotrophin which is required to induce folliculogenesis in women with hypogonadotrophic hypogonadism. There is, however, no evidence that GH supplementation is of significant clinical benefit in the management of patients with other ovulatory disorders--including PCOS--or in superovulation protocols for in vitro fertilization.

Randomised trial of growth hormone in short normal girls

BACKGROUND

There are few data on the long-term outcome of growth-hormone treatment in short normal children. We assessed the impact of growth-hormone treatment on pubertal development and near-final height in girls.

METHODS

In a randomised controlled trial, we studied ten girls, with a mean age of 8.07 years and height 2 SDs or more below the mean for their age, and eight short untreated controls matched for age, and 20 short untreated girls who did not give consent for randomisation. The girls received either 30 IU/m2 somatropin per week as daily subcutaneous injections or no treatment. We assessed pubertal staging and height gain every 6 months.

FINDINGS

Eight treated girls completed a mean of 6.2 years' therapy. By a mean age of 16.4 years, their mean height SD score had changed significantly from -2.42 to -1.14 (p=0.008) and they were, on average, 7.5 cm taller than the girls in the control group (height SD scores did not change significantly from -2.55) and 6.0 cm taller than the non-consent group. The timing of each pubertal stage, and the age and amplitude of peak height velocity were similar for all groups.

INTERPRETATION

Growth-hormone therapy effectively increased height SD score among short normal girls started on treatment in early to mid childhood, with no untoward effect on pubertal progression.

Efficacy and safety of one year of growth hormone therapy in steroid-dependent nephrotic syndrome

OBJECTIVES

To study the efficacy and safety of 1 year of growth hormone (GH) therapy in children with steroid-dependent nephrotic syndrome.

STUDY DESIGN

A prospective pilot, open study in which GH (mean dose 0.32 mg/kg per week) was administered for 1 year to 8 children with steroid-dependent nephrotic syndrome requiring prednisolone (mean dose 0.46 mg/kg per day) to maintain remission. Steroid dependence was defined as recurrence of proteinuria within 2 weeks of discontinuation of prednisolone, or when the dose was lowered below a critical level. At entry, all patients had been steroid dependent for at least 1 year. Anthropometric and bone mineral density measurements after treatment were compared with 1-year pretreatment data.

RESULTS

Pretreatment mean (+/-SD) chronologic age was 12.6 (+/-3.1) years, with a mean bone age of 9.1 (+/-2.0) years, with delayed puberty in five patients. The mean height velocity increased from 3.7 (+/-1.4) to 9.4 (+/-2.1) cm/yr after 1 year of treatment (p < 0.05). The mean height standard deviation score increased from -1.4 (+/-1.6) to -0.3 (+/-1.1), (p < 0.05). In the spine, the mean bone mineral density increased from 0.50 to 0.64 gm/cm2 (p < 0.05), and in the femoral neck, from 0.55 to 0.64 gm/cm2 (p < 0.05) after 1 year of treatment. Mean lean body mass increased from 58.1% to 62.6% (p < 0.01). There were no significant changes in creatinine clearance, fasting glucose, fasting insulin, or glycosylated hemoglobin levels. The mean bone age increased to 11.4 (+/-2.4) years, and pubertal stage advanced in 2 patients.

CONCLUSIONS

One year of GH therapy is effective in improving the height standard deviation score, height velocity, bone mineral density, and lean body mass of children with steroid-dependent nephrotic syndrome. There were no significant adverse effects. However, the bone age accelerated at a greater pace than the height age, and further studies are required to define the role of GH therapy in steroid-dependent nephrotic syndrome.

Growth during and 2 years after stopping GH treatment in prepubertal children with idiopathic short stature

Forty-six prepubertal children with idiopathic short stature (ISS), 39 boys and 7 girls, with a mean age of 7.4 +/- 1.8 (SD) years, and mean bone age of 4.5 +/- 1.5 years were treated by human growth hormone (GH) 0.1 U/kg/day s.c. for 30.5 +/- 16.2 months (M +/- SD) (2-5 years range) and were followed for 1-2 years after stopping GH. The mean net gain in height at the end of treatment was 1.03 +/- 0.6 SDS and the bone age SDS was accelerated by 0.95 +/- 1.05. Despite a transitory "catch-down" in growth velocity after stopping GH administration, there was a mean height gain at the end of 2 years follow-up of 0.87 SDS. Children who started treatment before age 6.5 benefited more than older ones. In conclusion, the gain in height observed in children with ISS by GH treatment was maintained during 2 years of follow-up after interruption of treatment. Even if this benefit is transitory and not permanent, it may help short children to achieve self-confidence and raise their physical performance at the critical period of school entry.

Unfavorable effects of growth hormone therapy on the final height of boys with short stature not caused by growth hormone deficiency

A group of 18 boys with non-growth hormone (GH)-deficient short stature without GH therapy (group A) and another group of 9 boys with non-GH-deficient short stature with GH therapy in doses of 0.5 IU (0.17 mg)/kg per week administered 5 to 6 times weekly (group B) were observed until they reached their final height. The mean duration of GH therapy was 4.2 years (range 3.2 to 5.0 years). These two groups were matched with respect to their standard deviation score (SDS) for bone age at the start of observation. Mean +/- SD of the final height for group A and group B was 162.0 +/- 5.4 cm and 154.2 +/- 4.2 cm, respectively. During the prepubertal period, height SDS for bone age of these two groups was not affected by GH therapy. During the pubertal period, however, height SDS for bone age remained constant for group A but decreased gradually for group B. Our observation indicates that for boys with non-GH-deficient short stature GH therapy does not improve height SDS for bone age during the prepubertal period, and in fact reduces it during the pubertal period, possibly resulting in a shorter final height than might have been attained naturally.

Breast cancer: further metabolic-endocrine risk markers?

There is evidence that increased oestrogen receptor (ER) expression in normal mammary epithelium may be a risk marker for the development of breast cancer. Insulin-like growth factor 1 (IGF1) is a potent inducer of mitosis and has been shown to synergize with oestrogen in stimulating the growth of human breast cancer in vitro. In these cells oestradiol has been shown to upregulate IGF type 1 receptor (IGFR), and recently a similar effect has been reported in normal human breast tissue xenografts in vivo. It has been postulated that the combined effect of oestradiol and IGF1 may stimulate proliferation in normal mammary epithelium and increase breast cancer risk. The bioavailability of IGF1 to the tissues is modulated by IGF-binding proteins (IGFBPs), and higher circulating levels of IGF1 and lower levels of IGFBP3 have been reported in breast cancer patients. Breast cancer specimens show a positive correlation between ER status and IGF receptor status, and also a negative correlation between ER status and IGFBP3 expression. Finally, ectopic growth hormone expression has been shown in a majority of specimens of normal and malignant breast tissue, and this may contribute to breast cancer risk, possibly by increasing the local level of bioavailable IGF1. Expansion of such findings may provide clinically useful markers of increased risk to breast cancer in women.

Growth hormone measurements versus auxology in treatment decisions: the Australian experience

Growth hormone (GH) therapy is regulated in Australia by an expert national government committee. A national database (OZGROW) enables regular audits and rational guideline revisions. In 1988 the guidelines were revised to allow eligibility on auxologic criteria alone because of difficulties in diagnosing GH deficiency (GHD) and GH responses in non-GH-deficient children. Initial entry criteria were height less than the 3rd percentile and growth velocity less than the 25th percentile of bone age. Growth hormone testing was continued in most children. More than 3100 children have been treated since 1988 (35 percent with GHD, 12.5% with Turner syndrome, and 52% with other non-GHDs). Five-year responses (change in height SD scores) were best in the group with complete GHD (+2) (which received the lowest dose of GH) and similar in other groups, including those with partial GHD (+1.5). The increase in final height is 4 to 6 cm in subjects with Turner syndrome. This data is not yet available for subjects with other non-GHDs. In 1994 the guidelines were revised to restrict use of GH therapy to subjects with height less than the 1st percentile, and cessation of GH therapy was brought forward to bone age 13.5 years for girls and 15 years for boys. Subjects with maturational delay were excluded because of the finding that in the presence of significant bone age delay height prognosis was good. New patient accruals have decreased since 1992, from 100/yr to less than 50/yr. Expenditures have also fallen, from $31 to $16 in 1994-1995, because of reduced patient numbers and GH pricing. Australian use of GH is 68.7% that of the United States and 42.2% that of Sweden and is in the midrange internationally. In conclusion, an auxology-based GH program coupled with a comprehensive national database enables rational and economic use of GH in short children.

Gonadal function and response to growth hormone (GH) in boys with isolated GH deficiency and to GH and gonadotropins in boys with multiple pituitary hormone deficiencies

OBJECTIVE

[corrected] To evaluate spermatogenesis in patients with isolated GH deficiency and multiple pituitary hormone deficiencies.

DESIGN

Treatment of isolated GH-deficient patients with recombinant human GH (weekly dose of 0.7 IU/kg) for 5.3 +/- 0.4 (mean +/- SD) years and cotreatment of multiple pituitary deficient patients with GH at the same dosage for 8.0 +/- 0.4 years and hCG (2,000 IU, three times per week) and hMG (500 IU, two times per week) for 13.7 +/- 1.1 months.

SETTING

Endocrine Pediatric Unit.

PATIENTS

Eight patients affected by isolated GH deficiency and seven by multiple pituitary hormone deficiencies.

MAIN OUTCOME MEASURES

Serum LH, FSH, and T, testicular volume, semen volume, density, count, and motility.

RESULTS

Patients with isolated GH deficiency completed their pubertal development in 19.0 +/- 3.5 months and patients with multiple pituitary hormone deficiencies in 13.7 +/- 1.1 months. At the end of puberty, the two groups of patients had similar testicular volume, penis size, sperm concentration, motility, and morphology, although T levels and seminal volume were lower in isolated GH-deficient patients than in multiple pituitary deficient patients.

CONCLUSIONS

The two groups of patients, treated specifically for their identified hormonal deficiencies, in the end had similar satisfactory reproductive results.

Spontaneous growth and response to growth hormone treatment in children with growth hormone deficiency and idiopathic short stature

Isolated idiopathic growth hormone deficiency (GHD) and idiopathic short stature (ISS) can be difficult to distinguish, but the therapeutical consequences are different. In this report the data on final height of untreated and treated children with GHD and ISS are reviewed. Untreated GH-deficient individuals who underwent spontaneous puberty (22 male, 14 female patients) reached a mean final height of 4.7 SD (range 3.9 to 6.0) below the population's mean. If puberty was induced (19 male patients), mean final height SD score (SDS) was -3.1. Traditional regimens of GH administration (2-4 injections/wk) in 236 children (184 boys, 52 girls) with GHD and spontaneous puberty resulted in a final height SDS of -2.8 (range -1.5 to -4.7). In 190 children in whom puberty was induced (139 boys, 51 girls) mean final height was -1.6 (range - -1.1 to -2.4). The mean gain in final height SDS is therefore estimated at 1.5-2.0 in average cases, and 3.5 in extreme cases. Preliminary data suggest that on present regimens mean final height may approach target height. In untreated boys with ISS the mean final height was 2-5 cm lower than that predicted before puberty, whereas in girls it was almost equal to the prediction. After GH treatment the mean final height was 0.4-3.0 cm higher than the predicted adult height, which results in an average net gain in final height SDS of approximately 0.5-0.8 (3-5 cm).