Lung volumes and respiratory muscle strength in adult patients with childhood- or adult-onset growth hormone deficiency: effect of 12 months' growth hormone replacement therapy

Vocal Characteristics of Children With Short Stature Before and After Growth Hormone Treatment

OBJECTIVE

To evaluate the vocal characteristics of children with short stature before and 12 months after growth hormone treatment.

MATERIAL AND METHODS

This analytical, observational cohort study included 23 children (age 5-11 years) diagnosed with short stature. Children in the short stature group (SSG) were matched (1:1) for age and sex with children with normal growth (normal stature group; NSG). Participants in the SSG underwent assessments before and 12 months after growth hormone treatment, while those in the NSG underwent the same assessments at baseline and 12 months. The assessments included evaluation of (A) vocal characteristics (history, vocal self-assessment, auditory-perceptual evaluation, and acoustic analysis), (B) anthropometry, (C) bone age, and (D) measurement of insulin-like growth factor-1 (IGF-1) levels.

RESULTS

Children in the SSG had more vocal complaints (P = 0.026) than those in the NSG. The groups were similar in terms of vocal self-assessment and auditory-perceptual evaluation (P = nonsignificant). Results of acoustic analysis were also similar for fundamental frequency (F 0) and perturbation measures (P for both = nonsignificant). F 0 and speech frequency decreased significantly at 12 months in both groups. F1 values were higher at 12 months in the NSG, while F2 values were significantly higher in the baseline evaluation in boys in the SSG. Children in the SSG compared with those in the NSG presented a greater increase in height measurements at 12 months, although the anthropometric means were lower in both evaluations (P < 0.001).

CONCLUSION

Vocal characteristics in children with short stature before and after treatment with growth hormone are comparable to those in children with normal growth.

Growth hormone deficiency with late-onset hypothalamic hypoadrenocorticism associated with respiratory and renal dysfunction: a case report

BACKGROUND

The prevalence of childhood-onset growth hormone (GH) deficiency (GHD) is estimated to be approximately 1 in 5000 or more, with the cause unknown in most cases (idiopathic isolated GHD). However, additional disorders of secretion of other pituitary hormones reportedly develop over time, with a frequency of 2-94% (median, 16%). Furthermore, median times to development of other anterior pituitary hormone deficiencies have been reported to be 6.4-9.4 years. On the other hand, adult patients affected by childhood-onset GHD reportedly develop impaired ventilation function due to reduced lung volumes and respiratory pressures, probably due to reductions in respiratory muscle strength. In addition, GH is known to play a role in stimulating the glomerular filtration rate (GFR), and the estimated GFR (eGFR) is decreased in patients with GHD.

CASE PRESENTATION

This case involved a 65-year-old woman. Her short stature had been identified at around 3 years of age, but no effective treatments had been provided. The patient was mostly amenorrheic, and hair loss became apparent in her late 30s. She developed hyperuricemia, dyslipidemia, and hypertension at 45 years of age. In addition, the patient was diagnosed with hypothyroidism at 50 years of age. At 58 years of age, endocrinological examination showed impaired secretion of thyroid-stimulating hormone, luteinizing hormone/follicle-stimulating hormone, and growth hormone, and magnetic resonance imaging showed an empty sella turcica. However, secretion ability of adrenocorticotropic hormone was retained. At 63 years of age, respiratory function tests confirmed a markedly restricted ventilation disorder (vital capacity, 0.54 L; percentage predicted vital capacity, 26.9%). Renal function had also decreased (eGFR, 25.0 mL/min/1.73 m²). Furthermore, she was diagnosed with hypothalamic secondary hypoadrenocorticism. The patient developed CO₂ narcosis at 65 years of age, and noninvasive positive pressure ventilation was started.

CONCLUSIONS

The rare case of a 65-year-old woman with childhood-onset GHD with panhypopituitarism, including late-onset secondary hypoadrenocorticism in her 60s, associated with severely impaired respiratory function and renal dysfunction, was reported. In GHD patients with risk factors for progression from isolated GHD to combined pituitary hormone deficiency, such as empty sella turcica, lifelong endocrinological monitoring may be important.

The promise of growth hormone in sport: doped or duped

Skeletal muscle is a target tissue of GH. Based on its anabolic properties, it is widely accepted that GH enhances muscle performance in sports. Athletic performance depends on muscle strength and the energy required to power muscle function. The energy required to power muscle function is derived from a continuum of anaerobic and aerobic sources. Molecular and functional studies provide evidence that in muscle GH stimulates the anaerobic and suppresses the aerobic energy system, in turn affecting power-based functional measures in a time-dependent manner. In recreational athletes, GH improves anaerobic capacity but has not been proven to significantly enhance muscle strength, power, or maximum rate of oxygen consumption. GH appears likely to selectively benefit sprint events and not physical performance that depends on strength and endurance. Arch Endocrinol Metab. 2019;63(6):576-81.

The enigmatic role of growth hormone in age-related diseases, cognition, and longevity

Growth hormone (GH) is secreted by the anterior pituitary gland and regulates various metabolic processes throughout the body. GH and IGF-1 levels are markedly reduced in older humans, leading some to hypothesize GH supplementation could be a viable "anti-aging" therapy. However, there is still much debate over the benefits and risks of GH administration. While an early study of GH administration reported reduced adiposity and lipid levels and increased bone mineral density, subsequent studies failed to show significant benefits. Conversely, other studies found positive effects of GH deficiency including extended life span, improved cognitive function, resistance to diseases such as cancer and diabetes, and improved insulin sensitivity despite a higher fat percentage. Thus, the roles of GH in aging and cognition remain unclear, and there is currently not enough evidence to support use of GH as an anti-aging or cognitive impairment therapy. Additional robust and longer-duration studies of efficacy and safety of GH administration are needed to determine if modulating GH levels could be a successful strategy for treating aging and age-related diseases.

Growth hormone replacement therapy improves hypopituitarism-associated hypoxemia in a patient after craniopharyngioma surgery: A case report

RATIONALE

There are some reports about hypoxemia related to hypopituitarism. However, little is known about the relationship between growth hormone deficiency (GHD) and hypoxemia.

PATIENTS CONCERNS

A 23-year-old female presented with severe hypoxemia after the operations of craniopharyngioma. Laboratory tests found that serum growth hormone (GH) levels were extremely low.

DIAGNOSIS

She was diagnosed with growth hormone deficiency-related hypoxemia.

INTERVENTIONS

In addition to oxygenation, low doses of GH replacement therapy was conducted for 3-month.

OUTCOMES

After 3-month r-hGH replacement therapy, hypoxemia was improved significantly and the level of serum GH was elevated.

LESSONS

We've already known that hypopituitarism may induce hypoxemia owing to multiple possible mechanisms according to previous literature. But little is known about growth hormone deficiency-related hypoxemia. Our case shows that GH replacement therapy is an effective treatment, and it's significant to examination the level of GH in serum for hypoxemia patients especially when the cause of hypoxemia is unknown.

Elevated (Pro)renin Receptor Expression Contributes to Maintaining Aerobic Metabolism in Growth Hormone Deficiency

Context

Growth hormone deficiency (GHD) leads to obesity and may induce tissue hypoxia. As (pro)renin receptor [(P)RR] is reported to contribute to the aerobic metabolism by stabilizing pyruvate dehydrogenase (PDH), it may play a substantial role in GHD.

Objective

We aimed to investigate serum soluble (P)RR [s(P)RR] concentration, the origin of s(P)RR, and significance of (P)RR in GHD.

Design, Setting, and Participants

Serum s(P)RR concentration was examined in 72 patients with pituitary diseases, including 32 patients with severe GHD (SGHD) and after GH replacement in 16 SGHD patients. Leptin-deficient ob/ob obese mice were treated with pegvisomant, a GH receptor antagonist, to explore the source of elevated serum s(P)RR in GHD. Adipocytes were cultured with 5% O₂ to examine the effects of hypoxia.

Results

Serum s(P)RR concentration was higher in patients with SGHD than in those without SGHD. Obesity was the important determinant of s(P)RR concentration. Serum s(P)RR concentration significantly decreased after GH replacement in SGHD patients. (P)RR mRNA expression was increased specifically in the adipose tissue (AT) of pegvisomant-treated obese mice compared with that of control obese mice. Hypoxia in cultured adipocytes increased (P)RR expression without affecting the PDH E1 β subunit (PDHB) expression; however, with (P)RR knockdown by small interfering RNA, hypoxia significantly decreased the expression of PDHB.

Conclusion

GHD patients showed increased serum s(P)RR concentration, possibly caused by obesity and hypoxia. (P)RR expression in AT of GHD patients may be elevated to help maintain aerobic metabolism under hypoxia. Thus, the elevated serum s(P)RR level may reflect hypoxia in ATs.

Action of GH on skeletal muscle function: molecular and metabolic mechanisms

Skeletal muscle is a target tissue of GH. Based on its anabolic properties, it is widely accepted that GH enhances muscle performance in sports and muscle function in the elderly. This paper critically reviews information on the effects of GH on muscle function covering structure, protein metabolism, the role of IGF1 mediation, bioenergetics and performance drawn from molecular, cellular and physiological studies on animals and humans. GH increases muscle strength by enhancing muscle mass without affecting contractile force or fibre composition type. GH stimulates whole-body protein accretion with protein synthesis occurring in muscular and extra-muscular sites. The energy required to power muscle function is derived from a continuum of anaerobic and aerobic sources. Molecular and functional studies provide evidence that GH stimulates the anaerobic and suppresses the aerobic energy system, in turn affecting power-based functional measures in a time-dependent manner. GH exerts complex multi-system effects on skeletal muscle function in part mediated by the IGF system.

Growth hormone replacement delays the progression of chronic heart failure combined with growth hormone deficiency: an extension of a randomized controlled single-blind study

OBJECTIVES

This study sought to evaluate the efficacy and safety of long-term growth hormone (GH) replacement therapy in GH-deficient patients with chronic heart failure (CHF).

BACKGROUND

Recent evidence indicates that growth hormone deficiency (GHD) affects as many as 40% of patients with CHF, and short-term GH replacement causes functional benefit. Whether long-term GH replacement also affects CHF progression is unknown.

METHODS

The study is an extension of a previous randomized, controlled single-blind trial that screened 158 consecutive CHF patients (New York Heart Association classes II to IV) and identified 63 who had GHD by the growth hormone releasing hormone plus arginine test. Fifty-six patients were randomized to receive either GH therapy or standard CHF therapy. Patients were evaluated at baseline and after a 4-year follow-up. The primary endpoint was peak oxygen consumption (VO2). Secondary endpoints included left ventricular (LV) ejection fraction and volumes, serum amino terminal fragment of the pro-hormone brain-type natriuretic peptide, quality of life, and safety.

RESULTS

Seventeen patients in the GH group and 14 in the control group completed the study. In the GH group, peak VO2 improved over the 4-year follow-up. The treatment effect was 7.1 ± 0.7 ml/kg/min versus -1.8 ± 0.5 ml/kg/min in the GH and control groups, respectively. At 4 years, LV ejection fraction increased by 10 ± 3% in the GH group, whereas it decreased by 2 ± 5% in control patients. The treatment effect on LV end-systolic volume index was -22 ± 6 ml and 8 ± 3 ml/m(2) in the GH and control groups, respectively (all p < 0.001). No major adverse events were reported in the patients who received GH.

CONCLUSIONS

Although this is a preliminary study, the finding suggests a new therapeutic approach to a large proportion of GHD patients with CHF.

Growth hormone and physical performance

There has been limited research and evidence that GH enhances physical performance in healthy adults or in trained athletes. Even so, human growth hormone (GH) is widely abused by athletes. In healthy adults, GH increases lean body mass, although it is possible that fluid retention contributes to this effect. The most recent data indicate that GH does not enhance muscle strength, power, or aerobic exercise capacity, but improves anaerobic exercise capacity. In fact, there are adverse effects of long-term GH excess such that sustained abuse of GH can lead to a state mimicking acromegaly, a condition with increased morbidity and mortality. This review will examine GH effects on body composition and physical performance in health and disease.

Respiratory failure was improved by growth hormone substitution in a patient with hypopituitarism

A 33-year-old man was referred to the Department of Respiratory Medicine in our hospital due to severe hypercapnic respiratory failure in March 2008. His respiratory function test showed severe restrictive pulmonary dysfunction, and respiratory muscle strength assessed by measuring maximal static expiratory and inspiratory mouth pressures was severely impaired. After non-invasive positive pressure ventilation was started, he was referred to the Endocrinology Department as he was diagnosed as hypopituitarism in his childhood. Pituitary MRI demonstrated pituitary stalk agenesis, and hormonal examination showed that he had severe growth hormone (GH) deficiency. GH replacement therapy was started in August 2008 and his arterial blood gas values and respiratory muscle strength were improved in 6 months. The current case demonstrated that GH deficiency could be a cause of severe respiratory failure.

Changes in endothelial dysfunction and associated cardiovascular disease morbidity markers in GH-IGF axis pathology

Arterial endothelial dysfunction is an early event in the pathogenesis of atherosclerosis and predisposes individuals to the deposition of unstable atherosclerotic plaques. It can also lead to increased arterial stiffness, which is an accepted cause of increased arterial pulse wave velocity (APWV). Endothelial dysfunction is reversed by recombinant human growth hormone (rhGH) therapy in patients with growth hormone (GH) deficiency (GHD), favorably influencing the risk for atherogenesis. Endogenous human growth hormone (hGH), secreted by the anterior pituitary, and levels of insulin-like growth factor-I (IGF-I), produced in response to hGH stimulation of the liver, peak during early adulthood, but decline throughout adulthood. It is suspected that low-grade inflammatory cardiovascular pathophysiologic markers such as homocysteine, nitric oxide, C-reactive protein (CRP), and fibrinogen and plasminogen activator inhibitor along with changes in lipid and glucose metabolism may all contribute to GHD-associated metabolic and cardiovascular complications. These effects are associated with increased APWV, but are attenuated by rhGH therapy in GHD. GH replacement increases IGF-I levels and reduces CRP and large-artery stiffness. Reviews of rhGH in the somatopause have not been overtly favorable. Whereas reviews of rhGH/rhIGF-I combinations in GH resistance are more positive than those for rhGH alone, their combined use in the somatopause is limited. Senescent individuals may benefit from such a combination.

Growth hormone administration: is it safe and effective for athletic performance

Human growth hormone (GH) is widely abused by athletes; however, there is little evidence that GH improves physical performance. Replacement of GH in GH deficiency improves some aspects of exercise capacity. There is evidence for a protein anabolic effect of GH in healthy adults and for increased lean body mass following GH, although fluid retention likely contributes to this increase. The evidence suggests that muscle strength, power, and aerobic exercise capacity are not enhanced by GH administration, however GH may improve anaerobic exercise capacity. There are risks of adverse effects of long-term abuse of GH. Sustained abuse of GH may lead to a state mimicking acromegaly, a condition with increased morbidity and mortality.

Growth hormone

Human growth hormone (hGH) is a proteohormone secreted by the pituitary gland. It acts through binding to the hGH receptor, inducing either direct effects or initiating the production of insulin-like growth-factor I (IGF-I), the most important mediator of hGH effects. Growth hormone is primarily known to promote longitudinal growth in children and adolescents, but has also various important metabolic functions throughout adult life. Effects of hGH on the adult organism are well established from studies with recombinant growth hormone (rhGH) therapy in growth hormone deficient subjects. In this particular group of patients, replacement of hGH leads to increased lipolysis and lean body mass, decreased fat mass, improvements in VO(2max), and maximal power output. Although extrapolation from these findings to the situation in well trained healthy subjects is impossible, and controlled studies in healthy subjects are scarce, abuse of hGH seems to be popular among athletes trying to enhance physical performance. Detection of the application of rhGH is difficult, especially because the amino acid sequence of rhGH is identical to the major 22,000 Da isoform of hGH normally secreted by the pituitary. Furthermore, some physiological properties of hGH secretion also hindered the development of a doping test: secreted in a pulsatile manner, it has a very short half-life in circulation, which leads to highly variable serum levels. Concentration alone therefore cannot prove the exogenous administration of hGH.Two approaches have independently been developed for the detection of hGH doping: The so-called "marker approach" investigates changes in hGH-dependent parameters like IGF-I or components of bone and collagen metabolism, which are increased after hGH injection. In contrast, the so-called "isoform approach" directly analyses the spectrum of molecular isoforms in circulation: the pituitary gland secretes a spectrum of homo- and heterodimers and - multimers of a variable spectrum of hGH isoforms, whereas rhGH consists of the monomeric 22,000 Da isoform only. This isoform therefore becomes predominant after injection of rhGH. Specific immunoassays with preference for the one or the other isoform allow analysis of the relative abundance of the 22,000 Da isoform. Application of rhGH can be proven when the ratio of this isoform relative to the others is increased above a certain threshold. Because the "marker method" and the "isoform method" have a different window of opportunity for detection, complementary use of both tests could be a way to increase the likelihood of detecting cheating athletes.

Maternal baicalin treatment increases fetal lung surfactant phospholipids in rats

Baicalin is a flavonoid compound purified from the medicinal plant Scutellaria baicalensis Georgi and has been reported to stimulate surfactant protein (SP)-A gene expression in human lung epithelial cell lines (H441). The aims of this study were to determine whether maternal baicalin treatment could increase lung surfactant production and induce lung maturation in fetal rats. This study was performed with timed pregnant Sprague-Dawley rats. One-day baicalin group mothers were injected intraperitoneally with baicalin (5 mg/kg/day) on Day 18 of gestation. Two-day baicalin group mothers were injected intraperitoneally with baicalin (5 mg/kg/day) on Days 17 and 18 of gestation. Control group mothers were injected with vehicle alone on Day 18 of gestation. On Day 19 of gestation, fetuses were delivered by cesarean section. Maternal treatment with 2-day baicalin significantly increased saturated phospholipid when compared with control group and total phospholipid in fetal lung tissue when compared with control and 1-day baicalin groups. Antenatal treatment with 2-day baicalin significantly increased maternal growth hormone when compared with control group. Fetal lung SP-A mRNA expression and maternal serum corticosterone levels were comparable among the three experimental groups. Maternal baicalin treatment increases pulmonary surfactant phospholipids of fetal rat lungs and the improvement was associated with increased maternal serum growth hormone. These results suggest that antenatal baicalin treatment might accelerate fetal rat lung maturation.

Association between serum insulin-like growth factor (IGF) I and IGF binding protein-3 and lung function

BACKGROUND

There is strong evidence that IGF-I and IGF binding protein 3 (IGFBP-3), as central mediators of endocrine and finally metabolic or anabolic effects of GH, were associated with increased lung size in acromegaly or a decrease of respiratory muscle pressures in patients with GH deficiency. The aim of the present study was to further clarify the impact of IGF-I and IGFBP-3 levels on lung volumes and respiratory pressures in a general adult population.

MATERIAL AND METHODS

From the Study of Health in Pomerania, 1326 subjects aged 25 to 85 yr participated in standardized pulmonary function testing. IGF-I and IGFBP-3 levels were measured with the Immulite 2500 system. Multivariable linear regression analyses adjusted for age, sex, body mass index, physical activity, and smoking were performed.

RESULTS

In men, positive linear associations between IGF-I and IGF-I/IGFBP-3 ratio with forced expiratory volume in 1 sec (FEV1) as well as with forced vital capacity (FVC) were detected across all ages, whereas in women this positive association was only detectable above 50 yr. Furthermore, the analyses indicated positive linear relations of IGF-I/IGFBP-3 ratio with FEV1 and FVC, respectively. No significant relations between IGF-I or IGFBP-3 and maximal inspiratory pressure was detectable in both sexes.

CONCLUSION

In conclusion, higher IGF-I levels were associated with higher lung volumes in men, whereas in women this association was only detectable in subjects older than 50 yr. Higher IGF-I values were not associated with increased respiratory muscle strength measured as maximal inspiratory pressure.

Inhaled growth hormone (GH) compared with subcutaneous GH in children with GH deficiency: pharmacokinetics, pharmacodynamics, and safety

BACKGROUND

Delivery of GH via inhalation is a potential alternative to injection. Previous studies of inhaled GH in adults have demonstrated safety and tolerability.

OBJECTIVE

We sought to assess safety and tolerability of inhaled GH in children and to estimate relative bioavailability and biopotency between inhaled GH and sc GH.

DESIGN/METHODS

This pediatric multicenter, randomized, double-blind, placebo-controlled, crossover trial had two 7-d treatment phases. Patients received inhaled GH and sc GH in the alternate phase. Placebo was administered by the route opposite from active drug. GH and IGF-I levels were measured at multiple time points. Pharmacokinetics were assessed using noncompartmental methods.

RESULTS

Twenty-two GH-deficient children aged 6-16 yr were treated. Absorption of GH appeared to be faster after inhalation with maximum serum concentrations measured at 1-4 h compared with 2-8 h for sc GH. Mean relative bioavailability for inhaled GH was 3.5% (90% confidence interval 2.7-4.4%). Mean relative biopotency, based on IGF-I response, was 5.5% (confidence interval 5.2-5.8%). Similar dose-dependent increases in mean serum GH area under the curve and IGF-I changes from baseline were seen after inhaled and sc GH doses. Inhaled GH was well tolerated and preferred to injection. No significant changes in pulmonary function tests were seen.

CONCLUSIONS

In this first pediatric trial of GH delivered by inhalation, it was well tolerated and resulted in dose-dependent increases in serum GH and IGF-I levels. This study establishes that delivery of GH via the deep lung is feasible in children.

Growth hormone-dependent changes in the rat lung proteome during alveorization

Growth hormone (GH) mRNA and protein have recently been demonstrated in the rat lung throughout the period of alveolarization (day 4-14 postnatally). The functional significance of this finding was therefore assessed, by determining the effects of GH mRNA knockout using aerosolized antisense oligodeoxynucleotides (ODN) directed against the GH gene. In a preliminary experiment, the effectiveness of the antisense GH ODN was demonstrated in a lung Type II epithelial cell line (L2 cells), in which constitutive GH mRNA expression was completely abolished by GH ODN transfection. Administration of the aerosolized GH ODN to 4-day-old rats for 10 days was accompanied by a widespread presence of its delivery liposomes within lung cells. Aerosolized GH ODN treatment decreased lung concentrations of IGF (insulin-like growth factor)-1 and increased concentrations of albumin, calcyclin binding protein, superoxide dismutase, RNA binding protein motif 3, and the alpha- and beta-subunits of ATP synthase and electron transfer flavoprotein. At least 32 other proteins (identified by 2D gel electrophoresis) were also significantly affected by the antisense GH ODN treatment. By changing the lung proteome, these results indicate hitherto unsuspected autocrine/paracrine actions of GH in developmental lung function.

Abuse of growth hormone among young athletes

The underground abuse of growth hormone (GH) among young athletes presents a challenge to medical professionals. Health care professionals providing knowledgeable guidance regarding healthy ways to improve performance and appearance, as well as accurate information regarding substances' perceived benefits, risks, and unknown qualities, is invaluable to the young athlete. Further research focused on the profile and motivation of young people who use GH is essential to understanding and intervening better with those who use these substances.

Short-term recombinant human growth hormone administration improves respiratory function in abstinent anabolic-androgenic steroid users

OBJECTIVES

To determine whether 6 days recombinant human growth hormone (rhGH) administration, in an abstinent anabolic-androgenic steroid (AAS) using group had any respiratory, endurance exercise and biochemical effects compared with an abstinent AAS control group.

METHODS

Male subjects (n=48) were randomly divided, using a single blind procedure into two groups: (1) control group (C) n=24, means+/-SD, age 32+/-11 years; height 1.8+/-0.06 m; (2) rhGH using group (0.019 mg kg(-1) day(-1)) (GH) n=24, means+/-SD, age 32+/-9 years; height 1.8+/-0.07 m. Anthropometry, respiratory muscle function and endurance exercise were investigated. Respiratory measurements examined, were forced expiratory volume in one second, forced vital capacity, maximum inspiratory pressure and maximum expiratory pressure. Endurance exercise was assessed by measuring peak oxygen uptake (VO(2)peak). Biochemical analysis included; haemoglobin, packed cell volume, glucose, sodium, urea, creatinine, total protein, albumin, testosterone and insulin like growth factor-I (IGF-I).

RESULTS

Forced expiratory volume in one second/forced vital capacity, maximum inspiratory pressure, maximum expiratory pressure, and IGF-I significantly increased compared with the control group (all P<0.05). Body mass index, fat free mass index, peak oxygen uptake, maximum inspiratory pressure, maximum expiratory pressure, IGF-I and serum sodium significantly increased, whilst body fat, total protein and albumin, significantly decreased within the GH group (all P<0.017).

CONCLUSION

The findings of this study indicated that short-term high dose rhGH increased aerobic performance and respiratory muscle strength in former AAS users.

Growth hormone (GH) receptor knockout mice reveal actions of GH in lung development

The presence of growth hormone (GH) and GH receptors (GHRs) in the lung suggests it is an autocrine/paracrine target site for pulmonary GH action and/or an endocrine site of pituitary GH action. Roles for GH in lung growth or pulmonary function are, however, uncertain. The possibility that pituitary and/or pulmonary GH have physiological roles in lung development has therefore been investigated in GHR knockout (KO or -/-) mice, using a proteomics approach to determine if an absence of GH-signaling affects the proteome of the developing lung. More than 600 proteins were detected by 2-DE in the lungs of control [GHR (+/+)] and GHR (-/-) mice at the end of the alveolarization period (at day 14 postnatally). Of these, 39 differed significantly in protein content at the p>0.05 level [6 were of higher abundance in the GHR (-/-) group, 33 were of lower abundance] and 17 differed at the p>0.02 level [5 of higher abundance in the GHR (-/-) group, 12 of lower abundance] and 7 were definitively identified by MS. Vimentin, a protein involved in cellular proliferation, was reduced in content by approximately 75% in the lungs of the GHR (-/-) mice. Three proteins involved in oxidative protection [SH3 domain-binding glutamic acid-rich-like protein, peroxiredoxin 6 (Prdx6), and isocitrate dehydrogenase 1] were also of lower content in the GHR (-/-) lungs (by approximately 88%, 81% and 70%, respectively). Prdx6 is also involved in lipid and surfactant metabolism, as is apolipoprotein A-IV, the lung content of which was reduced by approximately 73% in these mice. Proteasome 26S ATPase subunit 4, a protein involved in the non-lysosomal degradation of intracellular proteins, and electron flavoprotein alpha subunit , involved in intracellular metabolism, were also reduced in content in the lungs of the GHR (-/-) mice (by approximately 70% and 49%, respectively). These results therefore suggest that these proteins are normally dependent upon GH signaling, and that GH is normally involved in early lung growth, oxidative protection, lipid and energy metabolism and in proteasomal activity. These roles may reflect endocrine actions of pituitary GH and/or local autocrine/paracrine actions of GH produced within the lung.

Growth hormone expression in the perinatal and postnatal rat lung

It is now established that the lung is a target site for pituitary growth hormone (GH) action, because pathophysiological states of pituitary GH excess and deficiency are associated with impaired pulmonary function. The onset of lung development and differentiation is, however, before the ontogenic differentiation of pituitary somatotrophs. GH may be involved, nevertheless, in lung development, because it is present in extrapituitary tissues of preimplantation mouse embryos and in the lung buds of embryonic chickens. The possibility that GH may be expressed in the rat lung during fetal and neonatal development, therefore, has been assessed. GH mRNA was detected in the lung, and its 693-bp sequence was identical to that in the pituitary gland. By in situ hybridization, this transcript was found to be abundantly expressed in the lungs of embryonic day (ED) 17 rats in mesenchymal, mucosal epithelial, and smooth muscle cells. This transcript was expressed in neonates until at least day 14 postnatally and was localized to type I and II epithelial cells and to pulmonary tissue macrophages and alveolar macrophages. GH immunoreactivity paralleled GH mRNA cellular localization throughout the time course studied. This immunoreactivity was specific and was lost after antibody preabsorption. The perinatal and postnatal lung is, therefore, an extrapituitary site of GH gene expression during development. Given that the GH receptor is present in the lung from early development, lung GH may have autocrine and/or paracrine roles in lung growth or differentiation or in pulmonary function.

Expression of growth hormone and its receptor in the lungs of embryonic chicks

The lung is well established as being a postnatal target site for growth hormone (GH) action, since pathophysiological states of GH excess and deficiency are both associated with impaired pulmonary function. Pituitary GH is therefore probably involved in normal lung growth or development, although perinatal lung development occurs prior to the differentiation of pituitary somatotrophs and the ontogeny of pituitary GH secretion. The lung itself may, however, be a site of GH production during prenatal development, since a specific GH-response gene (a marker of GH activity) is expressed in the lungs of early chick embryos, in which GH immunoreactivity is widespread in many other peripheral tissues. We have assessed this possibility in embryonic chicks. A 690-bp cDNA, identical in size and nucleotide sequence to the full-length pituitary GH transcript, was amplified by reverse transcription/polymerase chain reaction from total RNA extracted from the lungs of embryos at 11, 13, 15, and 18 days of the 21-day incubation period. This transcript was localized by in situ hybridization to mesenchymal and epithelial cells of the developing lungs, in which specific GH immunoreactivity was similarly located. Intense GH immunoreactivity was also present after embryonic day 15 (ED15) in the smooth muscle surrounding blood vessels in the lung and surrounding the bronchioles. Lung GH immunoreactivity was primarily associated with a 15-kDa protein, rather than the 26-kDa protein in the pituitary gland. After the onset of pituitary GH secretion (at ED17), GH mRNA was barely detectable in the lungs of ED20 embryos, at the start of lung breathing. GH immunoreactivity was, however, still present in some cells in the lungs of ED20 embryos. GH-receptor mRNA and immunoreactivity were also widespread and abundant within the embryonic lung. Lung GH may thus have autocrine or paracrine roles in lung development or in pulmonary function prior to the ontogeny of the pituitary gland and the appearance of GH in peripheral plasma.

Short-term administration of supraphysiological recombinant human growth hormone (GH) does not increase maximum endurance exercise capacity in healthy, active young men and women with normal GH-insulin-like growth factor I axes

CONTEXT

Despite the fact that the use of GH as a doping agent in sports is widespread, little is known about its short-term effects.

OBJECTIVE

The objective was to study the effects of GH on exercise capacity.

DESIGN

A double-blind, placebo-controlled study was used, with a treatment period of 28 d.

SETTING

Subjects from general community studied ambulatory at a university hospital.

PARTICIPANTS

Thirty healthy active young normal volunteers (15 women and 15 men) were recruited by local announcement, and all completed the study.

INTERVENTION

All subjects were randomized to receive a low GH dose (0.033 mg/kg.d or 0.1 IU/kg.d), a high GH dose (0.067 mg/kg.d or 0.2 IU/kg.d), or placebo.

MAIN OUTCOME MEASURES

Power output and oxygen uptake on bicycle exercise were the main outcome measures.

RESULTS

We found no effect of the low or high dosages of GH on maximum oxygen uptake during exercise (mean +/- se for placebo, 45.2 +/- 1.6 to 45.2 +/- 2.1 ml/kg.min; GH low dose, 42.8 +/- 1.6 to 42.8 +/- 1.6 ml/kg.min; GH high dose, 44.8 +/- 3.4 to 44.8 +/- 2.2 ml/kg.min; not significant by two-way ANOVA). Neither was there any effect on maximum achieved power output during exercise or on blood pressure, heart rate, or the electrocardiographic ST level at rest or during exercise. GH significantly increased total body weight (P = 0.028), an effect predominantly ascribed to fluid retention (increased extracellular water volume), whereas muscle mass (as indicated by intracellular water volume) did not change. However, changes in the latter correlated to changes in physical performance, possibly due to different training efforts.

CONCLUSION

Administration of supraphysiological recombinant human GH during a period of 4 wk does not improve power output or oxygen uptake.

Growth hormone (GH) action in the developing lung: Changes in lung proteins after adenoviral GH overexpression

Growth hormone (GH) recently has been shown to be expressed in the neonatal rat lung during alveolarization. The possible functional importance of lung GH in lung function, therefore, has been assessed by determining changes in GH-responsive proteins in the developing rat lung after the overexpression of the GH gene in this tissue. GH overexpression was achieved using an adenovirus that expressed the mouse GH gene. This adenovirus was effective in inducing mouse GH expression in cultured rat lung L2 epithelial cells. It was also shown to be strongly expressed in the alveoli of 14-day-old rat pup lungs 10 days after it was administered by intratracheal injection, during a period of rapid lung development. Expression of the transgene in these pups was accompanied by changes in lung protein concentrations determined by two-dimensional gel electrophoresis and mass spectrometry. The lung concentrations of specific enzymes (nucleotide diphosphate kinase B, Cu/Zn superoxide dismutase, glutathione-S-transferase, and aldehyde reductase-1) were increased by the adenoviral expression of mouse GH, as were the concentrations of beta subunit G-protein calponin 2, beta-5 tubulin, retinoblastoma binding protein 4, and fetuin A. In contrast, the lung concentrations of haptoglobin and major acute phase alpha-1 protein were reduced by adenoviral expression of mouse GH. Although most of these proteins have not previously been identified as GH-responsive proteins, these results demonstrate actions of GH in the rat lung and support the possibility that GH acts as an autocrine/paracrine during early lung development.

Effects of exogenous growth hormone on resting pulmonary function in children with thermal injury

Burned children living beyond the acute phase of injury often have extensive physical functional limitations, such as impaired spirometry pulmonary function (PF). In patients with both lung disease and nutritional compromise, such as cystic fibrosis, studies suggest that growth hormone (GH) therapy improves PF. However, whether GH will improve PF in burned children is presently unknown. We therefore evaluated whether GH administration of 0.05 mg/kg/day for 1 year would improve PF in burned children. Thirty children, aged 7 to 18, with a 40% or more total body surface area burned were randomized into two groups and studied. One group received GH (n = 17) and the other received saline (n = 13). No differences were noted at hospital discharge between groups in age, % total body surface area, height, and weight. At 12 months after burn, both groups had similar height and weight. Baseline PF were below normal in both groups, but no statistical differences were noted between groups. At 1 year, there was a significant increase in PF in both groups; however, this increase in PF was similar in both groups. We conclude that the response in PF in burned children from the administration of GH prescribed for up to 1 year is limited.

Problems with GH doping in sports

Human hGH is listed as a prohibited class E substance by the International Olympic Committee (IOC), and its use is considered as doping. However, until today the likelihood of being punished for using recombinant hGH is very limited: once injected, it is believed to be undetectable by laboratories. No official test is implemented in the doping control procedures, and the only situation when athletes were found guilty of doping with hGH arose from actions of customs officers or policemen arresting athletes carrying ampoules with them. The primary reason for the lack of an accepted test method is the amino acid sequence identity between the main fraction of pituitary derived hGH and recombinant hGH, which makes it difficult to discriminate between endogenous and exogenous hGH. In addition, hGH is known to have a very short half-life time in circulation of around 15 min. Recent efforts of endocrine researchers led to the identification of two main strategies promising to be useful for the detection of recombinant hGH application, which are reviewed in this article: on the one hand, changes in GH-dependent parameters after administration of recombinant GH have been shown to be possible indicators of GH abuse, because the increase in various parameters following recombinant hGH administration exceeds the variability commonly observed in normal, healthy subjects. More directly, another approach focuses on changes in the hGH isoform pattern in serum occurring after injection of recombinant hGH. Because of the negative feedback on pituitary hGH secretion, the relative abundance of isoforms other than 22 kD are greatly reduced after administration of recombinant hGH, which only consists of the 22 kD hGH isoform.

Reduction of lung distensibility in acromegaly after suppression of growth hormone hypersecretion

Whether the growth of the lungs in acromegaly is due to alveolar hypertrophy or alveolar hyperplasia is a subject of debate. To discriminate these hypotheses, we compared pulmonary distensibility and diffusing capacity among 11 patients with active acromegaly and 11 matched control subjects, evaluating the response of pulmonary distensibility and diffusing capacity to suppression of growth hormone (GH) hypersecretion. We performed lineal and exponential analyses of quasistatic pressure-volume curves. Patients with active acromegaly had a greater TLC, lung compliance, and shape constant, K, than did normal subjects. We found no significant differences between the study groups in carbon monoxide diffusing capacity or diffusing capacity per unit of alveolar volume. After treatment, patients with inactive acromegaly showed a reduced TLC (6.95 +/- 1.40 [mean +/- SD] L versus 6.35 +/- 1.23 L), reduced lung compliance (3.61 +/- 0.90 L/kPa versus 2.36 +/- 0.79 L/ kPa), reduced K coefficient (2.62 +/- 0.65 kPa(-)(1) versus 1.35 +/- 0.40 kPa(-)(1)), and increased maximal recoil pressure (1.74 +/- 0.38 kPa versus 2.28 +/- 0.25 kPa). We conclude that the increased lung distensibility with normal diffusion capacity demonstrated in patients with active acromegaly, which was partly reversible after suppression of GH hypersecretion, suggests that lung growth in acromegaly may result from an increase in alveolar size.

Growth hormone replacement in adults with growth hormone deficiency: assessment of current knowledge

The recent availability of recombinant human growth hormone (GH) has led to intense investigation of the consequences of adult GH deficiency (GHD) and the effects of GH replacement. These studies have led to the identification of a characteristic syndrome of GHD consisting of decreased mood and well-being, with alterations in body composition and substrate metabolism. In both placebo-controlled and open studies, GH replacement therapy has consistently been shown to reverse or correct these features. Whether long-term GH replacement will result in a reduction of osteoporotic fractures, cardiovascular morbidity and mortality is not yet known. To date, no permanent serious adverse effects have been associated with GH replacement in GHD, and although currently expensive, it is anticipated that GH replacement will become routine in the treatment of the severely hypopituitary adult.

Does the age of onset of growth hormone deficiency affect cardiac performance? A radionuclide angiography study

BACKGROUND

GH and IGF-I seem to play a relevant role in cardiac development and performance. Long-standing GH deficiency (GHD) causes several abnormalities in cardiac structure and performance which ultimately determine an increased cardiovascular morbidity and mortality.

OBJECTIVE

To investigate whether the age of onset of GHD plays a role in determining the negative effects on the heart.

DESIGN

Open cross-sectional

PATIENTS

55 patients with adulthood-onset GHD and 36 healthy sex- and age-matched controls. Patients and controls were divided into 2 groups in line with age: 32 patients and 16 controls, were aged </= 35 years (young); while 23 patients and 20 controls were aged between 36 and 60 years (middle-aged). The estimated disease duration was similar in young (6.7 +/- 0.5 years) and middle-aged patients (8.1 +/- 1.2 years, P = 0.2).

STUDY PROTOCOL

All subjects underwent ECG, blood pressure and heart rate measurement, plasma IGF-I level assay, and equilibrium radionuclide angiography.

RESULTS

Plasma IGF-I levels were significantly lower in patients than in controls (P < 0.0001). When considered as a whole, no difference in systolic (SBP) and diastolic blood pressure (DBP) at peak exercise was found between patients and controls. However, a significant decrease of SBP at rest was found in young patients as compared to age-matched controls (P = 0.009), while a significant increase of DBP at rest was found in middle-aged patients as compared to age-matched controls (P = 0.03). In addition, in young patients, both resting (P = 0.02) and exercise heart rate (P = 0.01) were significantly lower than in controls. Diastolic filling when measured as end-diastolic volume (EVD/sec), was significantly reduced in middle-aged patients (P = 0.04). An impaired peak filling rate (PFR) (< 2.5 EDV/sec) was found in 30 patients (54.5%) and 10 controls (27.7%, chi2 = 5.3, P = 0.02): 17 young (53.1%) and 13 middle-aged patients (56.5%). A significant decrease of left ventricular (LV) ejection fraction (EF) at peak exercise was found in both patients groups (P < 0.0001) while LVEF at rest was lower only in middle-aged patients (P = 0.004). An impaired LVEF at rest (< 50%) was found in 13 patients (23.6%) and in none of controls (chi2 = 8.1, P = 0.004). The exercise induced changes in LVEF (DeltaEF) were significantly lower in both patients groups than in age-matched controls (P < 0.0001). Impaired LVEF response to exercise (< 5% increase vs. basal value) was found in 36 patients (65.4%) and in 5 controls (13.8%, chi2 = 21.3, P < 0.000): 21 young (65.6%) and 15 middle-aged patients (65.2%). The peak ejection rate (PER) was also significantly lower in young GHD patients than in controls (P < 0.001). Exercise duration and capacity were significantly reduced in both groups of GHD patients. In the patient group, age was significantly correlated with SBP and DBP levels both at rest (r = 0.612, and r = 0.516, respectively, P < 0.001) and at peak exercise (r = 0.4, P < 0.005 and r = 0.34, P < 0. 01, respectively), with exercise duration (r = - 0.383, P < 0.005) and capacity (r = - 0.355, P = 0.005). Disease duration was also correlated with IGF-I levels (r = - 0.319, P < 0.01), SBP levels at peak exercise (r = 0.352, P = 0.005), and LVEF at rest (r = - 0.254, P < 0.05). Finally, a significant correlation was found between IGF-I levels and DBP at peak exercise (r = 0.3, P < 0.05) and between GH peak at ARG + GHRH test and LVEF at rest (r = 0.232, P < 0.05). Exercise-induced changes in LVEF were significantly correlated with SBP levels at peak exercise (r = - 0.401, P < 0.005), PFR expressed as EDV/sec (r = - 0.306, P < 0.05) and SV/sec (r = - 0.292, P < 0.05). At multiple regression analysis in the patient group, age was the strongest predictor of SBP both at rest (t = 4.17, P < 0.0001) and at peak exercise (t = 2.32, P = 0.025), and capacity (t = - 2.84, P = 0.007). IGF-I levels were the strongest predictor of DBP at peak exercise (t = 2.2, P = 0.

Effect of low-dosage recombinant human growth hormone therapy on pulmonary function in hypopituitary patients with adult-onset growth hormone deficiency

An impairment of the pulmonary function has been described in adult patients with childhood-onset growth hormone deficiency (GHD). We examined forced vital capacity (FVC), forced expiratory volume (FEV1), total lung capacity (TLC), functional residual capacity (FRC), residual volume (VR) and the index of inspiratory strength, middle tidal volume and tidal inspiratory time ratio (TV/I), in 29 patients with adult-onset GHD. Data were compared with those obtained in 46 healthy control subjects. Only the FEV1/FVC ratio was statistically different (p = 0.04) between the two groups of subjects. In a group of 15 GHD patients low dosages (0.5-1 IU/day s.c., bedtime) of recombinant human GH (rh-GH; n. = 8 subjects) or placebo (n. = 7) were given at random for a 6-month period. A significant increase in IGF-I levels was noted in the rh-GH-treated group (p = 0.04) but not in the placebo group. After the 6-month period no statistically significant changes in pulmonary function were found between the rh-GH-treated and placebo-treated GHD patients. This study shows that adult-onset GHD patients suffer from minimal impairment of pulmonary function. Low rh-GH dosages able to induce an increase in IGF-I levels do not improve pulmonary function. The effect of rh-GH on respiratory muscle strength could be related to the age at which GHD diagnosis is made, or induced only by high rh-GH dosages given for a long time.