The influence of growth hormone status on physical impairments, functional limitations, and health-related quality of life in adults

On the functional capacity and quality of life of patients with acromegaly: are they candidates for rehabilitation programs?

[Purpose] This study compared patients having active acromegaly with those having controlled acromegaly in terms of peripheral muscle strength, body composition, and functional capacity. We also examined the associations between these measures. [Methods] A total of 14 patients with active acromegaly, 12 patients with controlled acromegaly, and 12 healthy controls were subjected to isometric dynamometry, surface electromyography, electrical bioimpedance, and a six-minute walk test. [Results] The active acromegaly group exhibited significantly more fat-free mass than the control group. With respect to the peripheral muscle performance, the controlled acromegaly group presented a significantly lower electromyographic median frequency than the control group. The quadriceps maximum strength was significantly lower in the controlled acromegaly group than in the control group. The fat-free mass was significantly correlated with the quadriceps maximum strength. The global scores of the Acromegaly Quality of Life Questionnaire were significantly correlated with the six-minute walk distance. [Conclusion] Patients with acromegaly have more fat-free mass, less peripheral muscle strength, and greater fatigability than healthy control subjects. These findings depend on the degree of hormonal control. In acromegalic patients, peripheral muscle strength is related to body composition, and functional capacity is correlated with quality of life.

The cost-effectiveness of growth hormone replacement therapy (Genotropin®) in hypopituitary adults in Sweden

BACKGROUND

To evaluate the cost-effectiveness of growth hormone (GH) treatment (Genotropin®) compared with no GH treatment in adults with GH deficiency in a Swedish societal setting.

METHODS

A Markov-type cost-utility simulation model was constructed and used to simulate, for men and women, morbidity and mortality for GH-treated and -untreated individuals over a 20-year period. The calculations were performed using current available prices concerning morbidity-related healthcare costs and costs for Genotropin®. All costs and treatment effects were discounted at 3%. Costs were expressed in Euro (1€ = 9.03 SEK). GH-treated Swedish patients (n = 434) were identified from the KIMS database (Pfizer International Metabolic Database) and untreated patients (n = 2135) from the Swedish Cancer Registry and the Hospital Discharge Registry.

RESULTS

The results are reported as incremental cost per quality-adjusted life year (QALY) gained, including both direct and indirect costs for GH-treated versus untreated patients. The weighted sum of all subgroup incremental cost per QALY was €15,975 and €20,241 for men and women, respectively. Including indirect cost resulted in lower cost per QALY gained: €11,173 and €10,753 for men and women, respectively. Key drivers of the results were improvement in quality of life, increased survival, and intervention cost.

CONCLUSIONS

The incremental cost per QALY gained is moderate when compared with informal thresholds applied in Sweden. The simulations suggest that GH-treatment is cost-effective for both men and women at the €55,371 (SEK 500,000 - the informal Swedish cost-effectiveness threshold) per QALY threshold.

Insulin-like growth factor-I (IGF-I) and clinical nutrition

IGF-I (insulin-like growth factor-I) is a peptide hormone, produced predominantly by the liver in response to pituitary GH (growth hormone), which is involved in a wide variety of physiological processes. It acts in an endocrine, paracrine and autocrine manner to promote growth. The production of IGF-I signals the availability of nutrients needed for its anabolic actions. Recently, there has been growing interest in its role in health and disease. IGF-I has long been known to be regulated by nutrition and dysregulated in states of under- and over-nutrition, its serum concentrations falling in malnutrition and responding promptly to refeeding. This has led to interest in its utility as a nutritional biomarker. A considerable evidence base supports utility for measurement of IGF-I in nutritional contexts. Its concentration may be valuable in providing information on nutritional status, prognosis and in monitoring nutritional support. However, it is insufficiently specific for use as a screening test for under nutrition as its serum concentration is influenced by many factors other than nutritional status, notably the APR (acute-phase response) and endocrine conditions. Concentrations should be interpreted along with clinical findings and the results of other investigations such as CRP (C-reactive protein). More recently, there has been interest in free IGF-I which holds promise as a nutritional marker. The present review covers nutritional regulation of IGF-I and its dysregulation in disease, then goes on to review recent studies supporting its utility as a nutritional marker in clinical contexts. Although not currently recommended by clinical guidelines, it is likely that, in time, measurement of IGF-I will become a routine part of nutritional assessment in a number of these contexts.

Growth hormone replacement therapy in patients with traumatic brain injury

In patients with severe traumatic brain injury (TBI), a growth hormone deficiency (GHD) is frequent and may contribute to the cognitive sequelae and reduction in quality of life (QoL). Recent studies have suggested that GH replacement therapy (GHRT) can improve processing speed and memory. The aim of the study was to analyze the efficacy of GHRT on cognition, activities of daily living (ADL), and QoL and the factors that predicted and contributed to these effects. We included patients at least 1 year after their TBI and assessed pituitary functions (with stimulation tests), cognition (attention, memory, and executive function), participation in ADL and QoL. GHD was treated for at least 1 year in 23 patients, who were compared with 27 non-treated patients. Other deficiencies were also treated. Measurements were performed at baseline and 1 year later. An analysis of variance of the factors group and session (p ≤ 0.05) showed that most cognitive parameters had improved at 1 year (evidencing a session effect). A stronger effect of GHRT (i.e. a group x session interaction) was found for Rey Osterrieth complex figure recall and 2/6 domains in the QoL questionnaire ("personal" and "functional"). Trends (p ≤ 0.07) were also found for spatial orientation and immediate recall in the verbal memory test. Greatest improvements were associated with lower performance before treatment. The magnitude of the improvements in ADL and QoL was moderately correlated with the improvement in cognition. In conclusion, replacement therapy can improve cognition and QoL in patients with TBI who have GHD, especially in those with severe disabilities.

Diagnosis and treatment of growth hormone deficiency in adults

The availability of synthetic recombinant human growth hormone (GH) in potentially unlimited quantities since the 1980s has improved understanding of the many nonstatural effects of GH on metabolism, body composition, physical and psychological function, as well as the consequences of GH deficiency in adult life. Adult GH deficiency is now recognized as a distinct if nonspecific syndrome with considerable adverse health consequences. GH replacement therapy in lower doses than those used in children can reverse many of these abnormalities and restore functional capacities toward or even to normal; if dosed appropriately, GH therapy has few adverse effects. Although some doubts remain about possible long-term risks of childhood GH therapy, most registries of adult GH replacement therapy, albeit limited in study size and duration, have not shown an increased incidence of cancers or of cardiovascular morbidity or mortality.

Psychosocial health and levels of employment in 851 hypopituitary Swedish patients on long-term GH therapy

CONTEXT

The psychosocial health and working capacity in hypopituitary patients receiving long-term growth hormone (GH) therapy are unknown.

OBJECTIVE

Psychosocial health and levels of employment were compared between GH deficient (GHD) patients on long-term replacement and the general population.

DESIGN AND PARTICIPANTS

In a Swedish nationwide study, 851 GHD patients [101 childhood onset (CO) and 750 adult onset (AO)] and 2622 population controls answered a questionnaire regarding current living, employment and educational level, alcohol consumption and smoking habits. The median time on GH therapy for both men and women with CO GHD was 9 years and for AO GHD 6 years, respectively.

RESULTS

As compared to the controls, the GHD patients were less often working full time, more often on sick leave/disability pension, and to a larger extent alcohol abstainers and never smokers (all; P<0.05). Predominantly CO GHD women and men, but to some extent also AO GHD women and men, lived less frequently with a partner and more often with their parents. Particularly AO GHD craniopharyngioma women used more antidepressants, while AO GHD men with a craniopharyngioma used more analgesics.

CONCLUSIONS

A working capacity to the level of the general population was not achieved among hypopituitary patients, although receiving long-term GH therapy. Patients were less likely to use alcohol and tobacco. The CO GHD population lived a less independent life.

The effects of two weeks of recombinant growth hormone administration on the response of IGF-I and N-terminal pro-peptide of collagen type III (P-III-NP) during a single bout of high resistance exercise in resistance trained young men

OBJECTIVE

Recombinant human growth hormone (rhGH) is used by some athletes and body builders with the aim of enhancing performance, building muscle and improving physique. Detection of the misuse of rhGH has proved difficult for a number of reasons. One of these is the effect of preceding exercise. In this randomised, double blind placebo-controlled study, we determined the effects of rhGH administration in male amateur athletes on two candidate markers of rhGH abuse, IGF-I and N-terminal pro-peptide of collagen type III (P-III-NP), following a bout of weightlifting exercise.

DESIGN

Sixteen men entered a four-week general weight training programme to homogenise their activity profile. They then undertook repeated bouts of standardised leg press weightlifting exercise (AHRET-acute heavy resistance exercise test). Blood samples were taken before and up to one hour after the AHRET. After the first laboratory visit (Test 1), the subjects were randomly assigned to receive daily injections of either rhGH (0.1 IU kg(-1) day(-1)) or placebo for two weeks. The AHRET was repeated after the two-week dosing period (Test 2) and a further test was undertaken following a one-week washout (Test 3).

RESULTS

There was no effect of exercise on either IGF-I or P-III-NP in any test. Both markers were markedly elevated at Test 2 (p<0.001), with P-III-NP remaining elevated at Test 3 in the GH administration group (p<0.05). Application of the GH-2000 discriminant function positively identified GH administration in 17 of 40 blood samples taken at Test 2 from the rhGH group and none from the placebo group.

CONCLUSION

The data show that rhGH results in elevated levels of IGF-I and P-III-NP in well-trained individuals and that leg press weightlifting exercise does not affect these markers. The GH-2000 discriminant function identified four of eight subjects taking rhGH with no false positive results.

Controlled release of human growth hormone fused with a human hybrid Fc fragment through a nanoporous polymer membrane

Nanotechnology has been applied to the development of more effective and compatible drug delivery systems for therapeutic proteins. Human growth hormone (hGH) was fused with a hybrid Fc fragment containing partial Fc domains of human IgD and IgG4 to produce a long-acting fusion protein. The fusion protein, hGH-hyFc, resulted in the increase of the hydrodynamic diameter (ca. 11 nm) compared with the diameter (ca. 5 nm) of the recombinant hGH. A diblock copolymer membrane with nanopores (average diameter of 14.3 nm) exhibited a constant release rate of hGH-hyFc. The hGH-hyFc protein released in a controlled manner for one month was found to trigger the phosphorylation of Janus kinase 2 (JAK2) in human B lymphocyte and to exhibit an almost identical circular dichroism spectrum to that of the original hGH-hyFc, suggesting that the released fusion protein should maintain the functional and structural integrity of hGH. Thus, the nanoporous release device could be a potential delivery system for the long-term controlled release of therapeutic proteins fused with the hybrid Fc fragment.

Impact of GH replacement therapy on sleep in adult patients with GH deficiency of pituitary origin

OBJECTIVES

We previously reported that adult patients with GH deficiency (GHD) due to a confirmed or likely pituitary defect, compared with healthy controls individually matched for age, gender, and BMI, have more slow-wave sleep (SWS) and higher delta activity (a marker of SWS intensity). Here, we examined the impact of recombinant human GH (rhGH) therapy, compared with placebo, on objective sleep quality in a subset of patients from the same cohort.

DESIGN

Single-blind, randomized, crossover design study.

METHODS

Fourteen patients with untreated GHD of confirmed or likely pituitary origin, aged 22-74 years, participated in the study. Patients with associated hormonal deficiencies were on appropriate replacement therapy. Polygraphic sleep recordings, with bedtimes individually tailored to habitual sleep times, were performed after 4 months on rhGH or placebo.

RESULTS

Valid data were obtained in 13 patients. At the end of the rhGH treatment period, patients had a shorter sleep period time than at the end of the placebo period (479±11 vs 431±19 min respectively; P=0.005), primarily due to an earlier wake-up time, and a decrease in the intensity of SWS (delta activity) (559±125 vs 794±219 μV(2) respectively; P=0.048).

CONCLUSIONS

Four months of rhGH replacement therapy partly reversed sleep disturbances previously observed in untreated patients. The decrease in delta activity associated with rhGH treatment adds further evidence to the hypothesis that the excess of high-intensity SWS observed in untreated pituitary GHD patients is likely to result from overactivity of the hypothalamic GHRH system due to the lack of negative feedback inhibition by GH.

Epicardial fat thickness significantly decreases after short-term growth hormone (GH) replacement therapy in adults with GH deficiency

BACKGROUND AND AIM

Growth Hormone Deficiency (GHD) is characterized by increased visceral fat accumulation. Echocardiographic epicardial fat thickness is a new marker of visceral adiposity. Aim of the present study was to evaluate whether epicardial fat thickness can significantly change and therefore serve as a marker of visceral fat reduction after short-term rhGH replacement therapy in patients with adult-onset GHD.

METHODS AND RESULTS

Echocardiographic epicardial fat thickness was measured in 18 patients (10 M, 8 F, age 48 ± 11.8 yrs, BMI 29 ± 5.9 kg/m(2)) with adult-onset GHD, at baseline and after 6 and 12 months of rhGH therapy and in 18 healthy matched controls, at baseline. Echocardiographic epicardial fat thickness, conventional anthropometric and metabolic parameters, body fat percentage and quality of life were also evaluated. Epicardial fat thickness in adult GHD patients was higher than in controls (9.8 ± 2.8 vs 8 ± 3 mm, p < 0.05). Epicardial fat thickness significantly decreased after 6-months of rhGH replacement therapy (from 9.8 ± 2.8 to 7.0 ± 2.3 mm, P < 0.01, i.e. -29% from baseline). After 12 months of rhGH replacement therapy, epicardial fat thickness showed a further significant decrease (from 7.0 ± 2.3 to 5.9 ± 3.1 mm, P < 0.01, i.e. -40% from baseline). No significant changes in BMI or waist circumference after 6 or 12 months of rhGH therapy were observed.

CONCLUSIONS

Echocardiographic epicardial fat thickness may represent a valuable and easy marker of visceral fat and visceral fat changes during rhGH replacement treatment in patients with adult-onset growth hormone deficiency.

Effects of growth hormone replacement therapy on bone mineral density in growth hormone deficient adults: a meta-analysis

Objectives. Growth hormone deficiency patients exhibited reduced bone mineral density compared with healthy controls, but previous researches demonstrated uncertainty about the effect of growth hormone replacement therapy on bone in growth hormone deficient adults. The aim of this study was to determine whether the growth hormone replacement therapy could elevate bone mineral density in growth hormone deficient adults. Methods. In this meta-analysis, searches of Medline, Embase, and The Cochrane Library were undertaken to identify studies in humans of the association between growth hormone treatment and bone mineral density in growth hormone deficient adults. Random effects model was used for this meta-analysis. Results. A total of 20 studies (including one outlier study) with 936 subjects were included in our research. We detected significant overall association of growth hormone treatment with increased bone mineral density of spine, femoral neck, and total body, but some results of subgroup analyses were not consistent with the overall analyses. Conclusions. Our meta-analysis suggested that growth hormone replacement therapy could have beneficial influence on bone mineral density in growth hormone deficient adults, but, in some subject populations, the influence was not evident.

Expression of a glycosylphosphatidylinositol-anchored ligand, growth hormone, blocks receptor signalling

We have investigated the interaction between GH (growth hormone) and GHR (GH receptor). We previously demonstrated that a truncated GHR that possesses a transmembrane domain but no cytoplasmic domain blocks receptor signalling. Based on this observation we investigated the impact of tethering the receptor's extracellular domain to the cell surface using a native lipid GPI (glycosylphosphatidylinositol) anchor. We also investigated the effect of tethering GH, the ligand itself, to the cell surface and demonstrated that tethering either the ecGHR (extracellular domain of GHR) or the ligand itself to the cell membrane via a GPI anchor greatly attenuates signalling. To elucidate the mechanism for this antagonist activity, we used confocal microscopy to examine the fluorescently modified ligand and receptor. GH–GPI was expressed on the cell surface and formed inactive receptor complexes that failed to internalize and blocked receptor activation. In conclusion, contrary to expectation, tethering an agonist to the cell surface can generate an inactive hormone receptor complex that fails to internalize.

Development and validation of a new questionnaire assessing quality of life in adults with hypopituitarism: Adult Hypopituitarism Questionnaire (AHQ)

Objective

To develop and validate the Adult Hypopituitarism Questionnaire (AHQ) as a disease-specific, self-administered questionnaire for evaluation of quality of life (QOL) in adult patients with hypopituitarism.

Methods

We developed and validated this new questionnaire, using a standardized procedure which included item development, pilot-testing and psychometric validation. Of the patients who participated in psychometric validation, those whose clinical conditions were judged to be stable were asked to answer the survey questionnaire twice, in order to assess test-retest reliability.

Results

Content validity of the initial questionnaire was evaluated via two pilot tests. After these tests, we made minor revisions and finalized the initial version of the questionnaire. The questionnaire was constructed with two domains, one psycho-social and the other physical. For psychometric assessment, analyses were performed on the responses of 192 adult patients with various types of hypopituitarism. The intraclass correlations of the respective domains were 0.91 and 0.95, and the Cronbach’s alpha coefficients were 0.96 and 0.95, indicating adequate test-retest reliability and internal consistency for each domain. For known-group validity, patients with hypopituitarism due to hypothalamic disorder showed significantly lower scores in 11 out of 13 sub-domains compared to those who had hypopituitarism due to pituitary disorder. Regarding construct validity, the domain structure was found to be almost the same as that initially hypothesized. Exploratory factor analysis (n = 228) demonstrated that each domain consisted of six and seven sub-domains.

Conclusion

The AHQ showed good reliability and validity for evaluating QOL in adult patients with hypopituitarism.

Psychometric performance of the CushingQoL questionnaire in conditions of real clinical practice

OBJECTIVE

To evaluate health-related quality of life (HRQoL) in Cushing's syndrome (CS) with the disease-generated CushingQoL questionnaire and to confirm its psychometric properties of test-retest reliability and sensitivity to change.

DESIGN

Clinical practice conditions in a tertiary referral center.

METHODS

The CushingQoL and EuroQoL questionnaires were administered at baseline and during follow-up and correlated with clinical parameters in 59 patients with CS. To check test-retest reliability, stable patients (either biochemically cured or with active hypercortisolism) were evaluated twice. To investigate sensitivity to change, new patients were evaluated at diagnosis and twice more following improvement after successful surgery.

RESULTS

At baseline, patients with active disease scored lower (indicating worse HRQoL) than those cured on the CushingQoL (46 ± 14 vs 58 ± 20, P<0.05) but not on the EuroQoL-visual analog scale (VAS; 64 ± 20 vs 70 ± 16, P NS). Test-retest reliability of CushingQoL was confirmed in stable patients, both in the 'cured group' (intraclass correlation coefficient (ICC)=0.78, n=34) and in the 'active group' (ICC=0.66, n=14). Sensitivity to change was confirmed in the 'improvement group' (n=11), as the CushingQoL score increased 4 ± 1.5 and 9 ± 3 months after surgery (P<0.01 and <0.001 respectively); the EuroQoL-VAS only improved after 9 ± 3 months (P<0.01). Effect sizes were 1.02 and 1.86 for CushingQoL at 4 ± 1.5 and 9 ± 3 months respectively. Finally, scores of both questionnaires were correlated (r=0.504; P<0.001).

CONCLUSIONS

The CushingQoL questionnaire shows good test-retest reliability and sensitivity to change in clinical practice conditions.

Discontinuing long-term GH replacement therapy--a randomized, placebo-controlled crossover trial in adult GH deficiency

CONTEXT

Adult GH deficiency (GHD) is associated with impaired quality of life (QoL) and increased cardiovascular risk. Continued long-term efficacy in terms of QoL and cardiovascular risk factors has been indicated in open surveillance studies.

OBJECTIVES

The aim was to study the impact of discontinuation of long-term GH replacement on QoL, body composition, and metabolism.

DESIGN AND SETTING

We conducted a randomized, double-blind, placebo-controlled 4-month crossover trial in a referral center.

PATIENTS

Sixty adult hypopituitary patients with GHD and more than 3 yr of continuous GH replacement therapy (mean treatment duration, 10 yr) participated in the study.

INTERVENTION

Patients received GH or placebo.

MAIN OUTCOME MEASUREMENTS

We measured QoL using validated questionnaires; body composition using computer tomography, dual-energy x-ray absorptiometry, and bioelectrical impedance spectroscopy; and insulin sensitivity using the short insulin tolerance test.

RESULTS

Mean serum IGF-I decreased from 168 ± 52 to 98 ± 47 μg/liter during the placebo period (P < 0.001). Two QoL domains (emotional reactions and positive well-being) in the Nottingham Health Profile and Psychological General Well-Being questionnaires deteriorated during placebo, compared with GH treatment (P < 0.05). Waist circumference and sc and visceral fat mass increased, and extracellular water and muscle area decreased during the placebo period (all P < 0.05). C-reactive protein and total-, low-density lipoprotein-, and high-density lipoprotein-cholesterol increased, and insulin sensitivity improved during placebo, compared to GH treatment (P < 0.05).

CONCLUSION

After more than 3 yr of GH replacement therapy, a 4-month period of placebo treatment caused self-perceived deterioration in QoL and increased abdominal fat accumulation. Moreover, markers of systemic inflammation and lipid status deteriorated, whereas insulin sensitivity improved. Long-term continuous GH replacement is needed to maintain therapeutic effects of GH on QoL and cardiovascular risk factors.

Effect of growth hormone replacement therapy on the quality of life in women with growth hormone deficiency who have a history of acromegaly versus other disorders

OBJECTIVE

To compare the response in quality of life (QoL) to growth hormone (GH) replacement in women with GH deficiency (GHD) and a history of acromegaly with that in women with GHD of other causes.

METHODS

Fifty-five women with GHD were studied: 17 with prior acromegaly and 38 with other causes of GHD. We compared two 6-month, randomized, placebo-controlled studies of GH therapy in women with hypopituitarism conducted with use of the same design-one in women with a history of acromegaly and one in women with no prior acromegaly. QoL was assessed with the following questionnaires: the QoL-Assessment of Growth Hormone Deficiency in Adults (AGHDA), the Symptom Questionnaire, and the 36-Item Short-Form Health Survey (SF-36).

RESULTS

The 2 groups had comparable mean pretreatment age, body mass index, and QoL scores and comparable mean GH dose at 6 months (0.61 ± 0.30 versus 0.67 ± 0.27 mg daily). After 6 months of GH replacement therapy, women with GHD and prior acromegaly demonstrated a greater improvement in AGHDA score, four SF-36 sub-scales (Role Limitations due to Physical Health, Energy or Fatigue, Emotional Well-Being, and Social Functioning), and the Somatic Symptoms subscale of the Symptom Questionnaire than did women with GHD of other causes. Poorer pretreatment QoL was associated with a greater improvement in QoL after administration of GH.

CONCLUSION

In this study, GH replacement therapy improved QoL in women with GHD and a history of acromegaly but not in women with GHD due to other hypothalamic and pituitary disorders. Further studies are needed to determine the long-term risks versus benefits of GH replacement in patients who develop GHD after definitive treatment for acromegaly.

Hormone replacement therapy and physical function in healthy older men. Time to talk hormones?

Improving physical function and mobility in a continuously expanding elderly population emerges as a high priority of medicine today. Muscle mass, strength/power, and maximal exercise capacity are major determinants of physical function, and all decline with aging. This contributes to the incidence of frailty and disability observed in older men. Furthermore, it facilitates the accumulation of body fat and development of insulin resistance. Muscle adaptation to exercise is strongly influenced by anabolic endocrine hormones and local load-sensitive autocrine/paracrine growth factors. GH, IGF-I, and testosterone (T) are directly involved in muscle adaptation to exercise because they promote muscle protein synthesis, whereas T and locally expressed IGF-I have been reported to activate muscle stem cells. Although exercise programs improve physical function, in the long-term most older men fail to comply. The GH/IGF-I axis and T levels decline markedly with aging, whereas accumulating evidence supports their indispensable role in maintaining physical function integrity. Several studies have reported that the administration of T improves lean body mass and maximal voluntary strength in healthy older men. On the other hand, most studies have shown that administration of GH alone failed to improve muscle strength despite amelioration of the detrimental somatic changes of aging. Both GH and T are anabolic agents that promote muscle protein synthesis and hypertrophy but work through separate mechanisms, and the combined administration of GH and T, albeit in only a few studies, has resulted in greater efficacy than either hormone alone. Although it is clear that this combined approach is effective, this review concludes that further studies are needed to assess the long-term efficacy and safety of combined hormone replacement therapy in older men before the medical rationale of prescribing hormone replacement therapy for combating the sarcopenia of aging can be established.

Growth hormone doping in sports: a critical review of use and detection strategies

GH is believed to be widely employed in sports as a performance-enhancing substance. Its use in athletic competition is banned by the World Anti-Doping Agency, and athletes are required to submit to testing for GH exposure. Detection of GH doping is challenging for several reasons including identity/similarity of exogenous to endogenous GH, short half-life, complex and fluctuating secretory dynamics of GH, and a very low urinary excretion rate. The detection test currently in use (GH isoform test) exploits the difference between recombinant GH (pure 22K-GH) and the heterogeneous nature of endogenous GH (several isoforms). Its main limitation is the short window of opportunity for detection (~12-24 h after the last GH dose). A second test to be implemented soon (the biomarker test) is based on stimulation of IGF-I and collagen III synthesis by GH. It has a longer window of opportunity (1-2 wk) but is less specific and presents a variety of technical challenges. GH doping in a larger sense also includes doping with GH secretagogues and IGF-I and its analogs. The scientific evidence for the ergogenicity of GH is weak, a fact that is not widely appreciated in athletic circles or by the general public. Also insufficiently appreciated is the risk of serious health consequences associated with high-dose, prolonged GH use. This review discusses the GH biology relevant to GH doping; the virtues and limitations of detection tests in blood, urine, and saliva; secretagogue efficacy; IGF-I doping; and information about the effectiveness of GH as a performance-enhancing agent.

Quality of life is impaired in association with the need for prolonged postoperative therapy by somatostatin analogs in patients with acromegaly

OBJECTIVE

To assess the influence of long-acting somatostatin analogs (SSTA) after initial pituitary surgery on long-term health-related quality of life (HR-QoL) in relation to disease control in patients with acromegaly.

DESIGN

This is a cross-sectional study in two tertiary referral centers in The Netherlands.

PATIENTS AND METHODS

One hundred and eight patients with acromegaly, in whom transsphenoidal (n=101, 94%) or transcranial (n=7, 6%) surgery was performed. Subsequently, 46 (43%) received additional radiotherapy and 41 (38%) were on postoperative treatment with SSTA because of persistent or recurrent disease at the time of study. All subjects filled in standardized questionnaires measuring HR-QoL. Disease control at the time of study was assessed by local IGF1 SDS.

RESULTS

IGF1 SDS were slightly higher in patients treated with SSTA in comparison with patients without use of SSTA (0.85±1.52 vs 0.25±1.21, P=0.026), but the percentage of patients with insufficient control (IGF1 SDS >2) was not different (17 vs 9%, P=0.208). Patients using SSTA reported poorer scores on most subscales of the RAND-36 and the acromegaly QoL and on all subscales of the multidimensional fatigue inventory-20. A subgroup analysis in patients with similar IGF1 levels (SSTA+, n=26, IGF1 SDS 0.44±0.72 vs SSTA-, n=44, IGF1 SDS 0.41±0.65) revealed worse scores on physical functioning, physical fatigue, reduced activity, vitality, and general health perception across all HR-QoL questionnaires in patients treated with SSTA.

CONCLUSION

QoL is impaired in association with the need for prolonged postoperative therapy by SSTA in patients with acromegaly despite similar IGF1 levels.

Common genetic variation in the IGF1 associates with maximal force output

PURPOSE

We clarified the effect of insulin-like growth factor-1 (IGF1), IGF-binding protein-3 (IGFBP3), interleukin-6 (IL6), and its receptor (IL6R) gene variants on muscular and aerobic performance, body composition, and on circulating levels of IGF-1 and IL-6. Single nucleotide polymorphisms (SNPs) may, in general, influence gene regulation or its expression, or the structure and function of the corresponding protein, and modify its biological effects. IGF-1 is involved in the anabolic pathways of skeletal muscle. IL-6 plays an important role in muscle energy homeostasis during strenuous physical exercise.

METHODS

Eight hundred forty-one healthy Finnish male subjects of Caucasian origin were genotyped for IGF1 (rs6220 and rs7136446), IGFBP3 (rs2854744), IL6 (rs1800795), and IL6R (rs4537545) SNPs, and studied for associations with maximal force of leg extensor muscles, maximal oxygen consumption, body fat percent, and IGF-1 and IL-6 levels. Analytic methods included dynamometer, bicycle ergometer, bioimpedance, ELISA, and polymerase chain reaction assays.

RESULTS

All investigated SNPs conformed to Hardy-Weinberg equilibrium with allele frequencies validated against CEU population. Genotype CC of rs7136446 associated with higher body fat and increased maximal force production. Genotype CC of the IGFBP3 SNP rs2854744 and TT genotype of the IL6R SNP rs4537545 associated with higher IL-6 levels. In logistic regression analysis, allele C of the rs2854744 decreased odds for lower body fat. None of the studied SNPs associated with aerobic performance.

CONCLUSIONS

Our data suggest that common variation in the IGF1 gene may affect maximal force production, which can be explained by the role of IGF-1 in the anabolic pathways of muscle and neurotrophy. Variations in the IGF1 and IGFBP3 gene may result in higher body fat and be related to alterations of IGF-1-mediated tissue growth.

What are critical outcome measures for patients receiving pituitary replacement following brain injury?

There are scant prospective studies defining improvements in critical outcome measures with hormone replacement in hypopituitarism secondary to brain injury. We review the tests of cognition and physical function and summarize their use for subjects that are deficient in anterior hormone production during anterior pituitary hormone replacement in brain injury and propose these as the minimal tests that are feasible for a physician to perform in a clinical setting. We summarize the studies conducted to assess outcome measures after brain injury and also report preliminary findings for improvements in cognition and physical function in subjects with brain injury and GH deficiency.

Impaired aerobic exercise adaptation in children and adolescents with craniopharyngioma is associated with hypothalamic involvement

OBJECTIVE

Many patients treated for craniopharyngioma (CP) complain of a relative incapacity for physical activity. Whether this is due to an objective decrease in adaptation to exercise is unclear. We assessed exercise tolerance in children with surgically treated CP and appropriate pituitary hormone replacement therapy compared with healthy controls and we examined the potential relationships with hypothalamic involvement, GH replacement, and the catecholamine deficiency frequently observed in these subjects.

DESIGN AND METHODS

Seventeen subjects (12 males and five females) with CP and 22 healthy controls (14 males and eight females) aged 15.3±2.5 years (7.3-18 years) underwent a standardized cycle ergometer test. Maximum aerobic capacity was expressed as the ratio of VO(2max) to fat-free mass (VO(2max)/FFM), a measure independent of age and fat mass in children.

RESULTS

VO(2max)/FFM was 20% lower in children with CP compared with controls (P<0.05), even after adjustment for gender. Children with hypothalamic involvement (n=10) had a higher percentage of fat mass (P<0.05) than those without hypothalamic involvement (n=7) and lower VO(2max)/FFM (P<0.05), whereas children without hypothalamic involvement had VO(2max)/FFM close to that of controls (P>0.05). GH treatment was associated with a significant positive effect on aerobic capacity (P<0.05) only in the absence of hypothalamic involvement. No relationship was found between exercise capacity parameters and daily urine epinephrine excretion or epinephrine peak response to insulin-induced hypoglycemia.

CONCLUSIONS

Children with CP have a decrease in aerobic capacity mainly related to hypothalamic involvement. The hypothalamic factors altering aerobic capacity remain to be determined.

Basal growth hormone concentration increased following a weight loss focused dietary intervention in older overweight and obese women

OBJECTIVES

Growth and sex steroid hormones decrease with aging and obesity. The effect of dietary weight loss and exercise training lifestyle interventions was examined on hormones as well as determining their relationships with physical function in older obese and overweight adults.

DESIGN

Individuals were randomized into one of four 18 month interventions: Healthy Lifestyle (HL), Exercise, Diet, and Exercise-Diet.

SETTING

Clinical research setting with facility based exercise and nutrition education and behavior classrooms.

PARTICIPANTS

Older (≥60 yrs) overweight and obese (BMI≥28 kg/m(2)) adults with knee osteoarthritis (n=309) were recruited for the study.

INTERVENTION

Weight loss goal for Diet groups was ≥5%. Exercise groups trained (mostly walking and resistance training) 3 days/week for 60 min/session.

MEASUREMENTS

Body weight, growth hormone (GH), corticosterone, sex-hormone binding globulin (SHBG), testosterone, and dehydroepiandrosterone (DHEA) were measured at baseline, 6, and 18 months. Physical function was determined through performance task (6-min walking distance) and self-reported questionnaires (Western Ontario McMaster University Osteoarthritis Index-WOMAC) at similar time points.

RESULTS

Diet, Exercise, and Exercise-Diet groups lost 4.9%, 3.5%, and 6.2% of their weight at 18 months, respectively. There was a significant diet treatment effect on GH levels in women as higher concentrations of this hormone were apparent following dietary weight loss intervention (p=0.01). No other hormones were affected by either diet or exercise treatments in men or women. A significant inverse correlation between baseline 6-minute walking distance and SHBG (r=-0.33) was found in men.

CONCLUSION

The increase in basal GH levels from the diet treatment in women suggests that this lifestyle behavior intervention may mitigate the age- and obesity-related decreases in growth hormone levels, to help preserve muscle mass, strength, and physical function in older adults.

Evaluation of the bone status in high-level cyclists

The purpose of this study was to evaluate the bone status in highly trained professional cyclists subjected to regular training and tough competitions. Bone mineral density (BMD) was measured at different regions of interest by dual-energy X-ray absorptiometry, and main biological parameters related to bone metabolism were obtained in 29 cyclists. Lumbar BMD was 0.94 ± 0.01g/cm(2) (Z-score=-1.28 ± 0.07), and 1 cyclist out of 4 had an abnormally low value (Z-score <-2). The mean Z-score at the total femoral site was -1.22 ± 0.21, and 45% of athletes had an Z-score of <-2. All femoral neck BMD values were within normal boundaries. The lowest BMD Z-score was measured at the midradius or 1/3 proximal site with a mean Z-score of -1.77 ± 0.78, but only 3 cyclists (15%) had Z-scores <-2. Biochemical parameters of bone formation (serum osteocalcin and alkaline phosphatase) were normal. Three cyclists had low 25-hydroxyvitamin D levels. Blood testosterone and thyroid stimulating hormone were in the normal range. Insulin-like growth factor 1 levels were in the normal range; however, a significant inverse correlation was found with lumbar BMD (r=0.495; p=0.003). We confirm that cycling has no positive effect on BMD, BMD being often lower than in normal controls at the lumbar site; femoral BMD is less concerned. The absence of beneficial changes at the spine can be explained by biomechanical conditions related to the cyclists' position, reducing loading strains. It is necessary to pay greater attention to the bone status of high-level athletes to prevent an increased risk of fractures.

Medical therapy of acromegaly

This paper outlines the present status of medical therapy of acromegaly. Indications for permanent postoperative treatment, postirradiation treamtent to bridge the interval until remission as well as primary medical therapy are elaborated. Therapeutic efficacy of the different available drugs-somatostatin receptor ligands (SRLs), dopamine agonists, and the GH antagonist Pegvisomant-is discussed, as are the indications for and efficacy of their respective combinations. Information on their mechanism of action, and some pharmakokinetic data are included. Special emphasis is given to the difficulties to define remission criteria of acromegaly due to technical assay problems. An algorithm for medical therapy in acromegaly is provided.

Early changes in body composition after cessation of growth hormone therapy in childhood-onset growth hormone deficiency

At final height, somatic maturity has not been reached yet. We investigated bone and body composition in patients, who completed pediatric growth hormone (GH) treatment at final height. After a mean period of 0.55 ± 0.17 yr off GH treatment 90 (66 m/24 f) childhood-onset growth hormone deficiency (GHD) patients were reinvestigated for GHD by insulin tolerance testing at a mean age of 17.52 ± 1.50 yr. Thirty-seven (25 m/12 f) patients remained GH deficient (persistent GHD). Bone and body composition were measured using peripheral quantitative computed tomography of the nondominant forearm. Bone mineral density (BMD) was within normal limits. Total cross-sectional bone area Z-score (0.64 ± 1.3) was significantly higher as a result of an enlarged medullary cavity Z-score (1.12 ± 1.2) leading to reduction of cortical thickness Z-score (-1.21 ± 1.0). Patients with persistent GHD had a significantly higher fat mass (13.3 ± 8.7 and 6.8 ± 4.6 cm(2), p<0.05), which was more pronounced in multiple pituitary hormone deficiency patients. Shortly after cessation of GH treatment in patients treated for childhood-onset GHD age adequate normal BMD and enlarged diaphysis was detectable. Patients with persistent GHD status had a significant higher fat mass.

The brazilian version of the Quality of Life Assessment of Growth Hormone Deficiency in Adults (QoL-AGHDA): Four-stage translation and validation

OBJECTIVE

This study reports on the Brazilian Portuguese adaptation of the QoL-AGHDA (Quality of Life Assessment of Growth Hormone Deficiency in Adults) for use in adult growth hormone deficient (GHD) patients.

MATERIALS AND METHODS

The translation process adopted the dual panel methodology. The questionnaire was tested through field-test interviews (16 GHD patients). In the final stage, data from 120 GHD patients (81 included in a test-retest analysis) were analyzed for internal consistency, test-retest reliability, convergent validity and validity among known groups.

RESULTS

The translation panels were successful and the draft version was amended to improve the wording as a result of the field-test interviews. Cronbach's alpha was 0.90 and test-retest reliability 0.88. QoL-AGHDA scores had the expected pattern of association with NHP scale scores and QoL-AGHDA was able to differentiate significantly between patients based on patient-reported general health (p < 0.01) and QoL (p < 0.01).

CONCLUSIONS

The adaptation of the QoL-AGHDA for a Brazilian population was successful and the adapted questionnaire was shown to be reliable and valid.

Growth hormone doping: a review

The use of growth hormone (GH) as a performance enhancing substance was first promoted in lay publications, long before scientists fully acknowledged its benefits. It is thought athletes currently use GH to enhance their athletic performance and to accelerate the healing of sporting injuries. Over recent years, a number of high profile athletes have admitted to using GH. To date, there is only limited and weak evidence for its beneficial effects on performance. Nevertheless the “hype” around its effectiveness and the lack of a foolproof detection methodology that will detect its abuse longer than 24 hours after the last injection has encouraged its widespread use. This article reviews the current evidence of the ergogenic effects of GH along with the risks associated with its use. The review also examines methodologies, both currently available and in development for detecting its abuse.

Deriving reference values and utilities for the QoL-AGHDA in adult GHD

BACKGROUND

Quality of life (QoL) measures are important in growth hormone (GH) deficiency (GHD) in adults. Ideally, for use in health economics, QoL should be expressed in utilities. The aim of this study was to obtain reference values and utilities for QoL of GHD in adults in Belgium and the Netherlands.

METHODS

The study was conducted in three stages: (1) The Quality of Life-Assessment for Growth Hormone Deficiency in Adults (QoL-AGHDA) and the EQ-5D were administered in a representative sample of 6,875 individuals from the Belgian and 1,400 individuals from the general Dutch population. The EQ-5D(index) can be used to estimate utilities. Using a regression, utilities were predicted from the QoL-AGHDA. (2) QoL-AGHDA scores were obtained from 299 Belgian and 234 Dutch adult patients with GHD and no GH replacement. These scores were converted to utilities and compared the burden of disease with other patient groups. (3) To test the criterion validity, the 'standard' EQ-5D(index) was used in a subsample of 64 Dutch GHD patients and compared with the predicted utilities.

RESULTS

We obtained data from 1,026 Belgian (response rate = 15%) and 1,038 Dutch respondents (response rate = 74%). The Belgian mean QoL-AGHDA value was 6.95 (90% range = 14.00), and the Dutch mean was 5.48 (range = 13.00). The R (2) of the regression model to predict the EQ-5D(index) was 0.360 (Belgium) and 0.482 (the Netherlands). We demonstrated a considerable burden of disease in GHD patients, comparable to patients with hypertension or with type II diabetes. The criterion validity was 0.407 (intraclass correlation, ICC).

CONCLUSIONS

Interventions in GHD can now be evaluated more validly in Belgium and the Netherlands.

[New insights in growth hormone physiology and pathophysiology]

This review focuses on new aspects in growth hormone (GH) biology and pathophysiology presented at the Endocrine Society's meeting, in San Diego, in June 2010. First, we will describe recent advances in the understanding of cytokine hormone signaling via STAT5 in mammary gland development, highlighting the primary role of miR193b for differentiation of mammary stem cells into alveolar progenitor cells. We will examine the potential implication of endocrine and autocrine GH for mammary gland carcinogenesis. Three novel murine models bearing tissue-specific inactivation of GH receptor or JAK2 bring new insights into the large spectrum of GH effects on energy homeostasis. We will also report new data supporting a paracrine regulation of GH secretion in women by estrogen's action in the brain. Thereafter we will question the reasons for GH abuse for doping by assessing the hormonal impact on body composition and physical performance in recreational athletes. Finally, we will discuss the controversial issue of GH replacement in acromegalic patients presenting GH deficiency after treatment of acromegaly.

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.

Interleukin 1 receptor antagonist is associated with changes in body composition during physiological GH substitution in patients with adult-onset growth hormone deficiency

OBJECTIVE

We examined the effect of GH substitution on adipose tissue-derived hormones and cytokines and sought to identify predictors for changes in body composition during therapy. Long-standing adult-onset GH deficiency (AO-GHD) is associated with increased body fat mass (FM) which, through production of hormones and inflammatory cytokines from adipose tissue, may contribute to different manifestations of the metabolic syndrome.

DESIGN, PATIENTS AND MEASUREMENTS

Fifty-five patients with AO-GHD (24 women, 31 men, mean age 49 years) were enrolled in a placebo-controlled, double-blind crossover study. GH therapy was individually dosed to obtain an IGF-I concentration within the normal range for age and sex. GH and placebo were administered for 9 months each, separated by a 4-month washout period. Adipose tissue-derived cytokines were measured by enzyme immunoassay.

RESULTS

GH treatment was associated with a significant decrease in IL-1 receptor antagonist (IL-1Ra) compared to placebo, which correlated with declining body FM (truncal and total) after GH substitution. The change in IL-1Ra was the strongest predictor of the variation in BFM in regression models. No changes were observed for leptin, adiponectin, soluble TNF receptor 1 or interleukin (IL)-8.

CONCLUSION

The data indicate a possible unrecognized association between IL-1Ra and changes in body composition during GH substitution and suggest further research on the interaction between the GH-IGF axis and the IL-1 system.

Fatigue, endocrinopathies, and metabolic disorders

Fatigue is a frequent reason for seeking medical attention. Endocrine dysfunction is a common etiology of fatigue. In fact, thyroid function is usually one of the first explanations on the list of possible diagnoses. The symptoms associated with endocrinopathies are frequently "nonspecific," and psychiatric disease or psychological disorders need to be differentiated. Often, this can be accomplished using biological measures of hormone function, such as measures of thyroid, pituitary, parathyroid, and adrenal hormone levels. The field of endocrinology is highly dependent on an algorithmic approach to differential diagnosis using hormone levels as the guide. The use of self-reports helps identify at-risk patients, and raises suspicions about whether there is an abnormality, but diagnosis is dependent on laboratory values. Metabolic abnormalities, such as hyper- or hypoglycemia, dyslipidemia, and gonadal dysfunction can also contribute to fatigue. A better understanding of the interactions among hormones, their releasing factors, and regulation of inflammation will help identify abnormalities early and help distinguish endocrinopathies from other causes of fatigue. Early identification of these abnormalities may reduce end-organ damage and improve treatment strategies.

Prevalence of growth hormone deficiency in adult polytransfused β-thalassemia patients and correlation with transfusional and chelation parameters

BACKGROUND

Dysfunction of GH-IGF-I axis has been described in many patients affected by β-thalassemia major (TM), especially in children and in adolescents. Recent studies have demonstrated the necessity to evaluate adult patients affected by TM to establish the presence of this alteration which could be relevant in the pathogenesis of cardiac and bone disease, frequently present in this hematological condition. The pathogenesis of this alteration, correlated in the past with iron overload, is not yet completely understood.

AIM

The aim of this paper is to evaluate GH-IGF-I axis in a group of adult polytransfused β-thalassemic patients (TM) and to correlate the results with transfusional and chelation parameters.

SUBJECTS AND METHODS

We performed an arginine plus GHRH stimulation test in 28 adult TM patients. Ferritin, IGF-I, liver enzymes, and liver iron concentration, assessed by a superconducting quantum interference device (SQUID) susceptometer were also determined. Moreover, in each patient we evaluated the bone status by a dual-energy X-ray absorptiometry study.

RESULTS

We found the presence of GH deficit in 9 patients (32.1%). There were no significant differences between the two groups regarding the value of ferritin, liver enzymes, and liver iron concentration, assessed by SQUID. The group affected by GH deficit showed a worse bone profile.

CONCLUSIONS

This study confirms the necessity to screen the status of GH/IGF-I axis in this group of patients, even in adult age. The presence of GH deficiency does not seem to be correlated with the efficacy parameters of transfusional and chelation therapy. Other mechanisms, additional to iron overload, could therefore play a role in the pathogenesis of this clinical condition. The presence of GH deficit seems to be very important on clinical aspects, like bone disease, that are crucial for quality of life in these patients.

The effect of growth hormone (GH) replacement on muscle strength in patients with GH-deficiency: a meta-analysis

CONTEXT/OBJECTIVES

GH replacement increases muscle mass and reduces body fat in growth hormone deficiency (GHD) adults. A recent meta-analysis has demonstrated that this improvement in body composition is associated with improved exercise performance. The current meta-analysis was carried out to determine whether high-quality evidence exists to support a beneficial effect of GH replacement on strength.

DESIGN/METHODS

An extensive Medline search/literature review identified eight studies with utilizable, robust data, involving 231 patients in nine cohorts. Previously unpublished data were sought from authors and obtained in two cases. All studies included were randomized, double-blind, placebo-controlled, of parallel or cross-over design and of an average 6.7 months duration. Information was retrieved in uniform format, with data pertaining to patient numbers, study-design, GH-dose, mean age, IGF-I levels and muscle strength measurements (isometric or isokinetic quadriceps strength) recorded. Data were analysed using a fixed-effects model, utilizing continuous data measured on different scales. A summary effect measure (d(s)) was derived for individual strength variables, whereas an overall summary effect was derived from the sum of all studies incorporating different variables; 95% CIs were calculated from the weighted variances of individual study effects.

RESULTS

Analysis revealed no significant improvement, neither when all studies were combined (d(s) = +0.01 +/- 0.26) nor when measured individually (isometric quadriceps strength, d(s) = +0.02 +/- 0.32 and isokinetic quadriceps strength, d(s) = 0.00 +/- 0.45).

CONCLUSIONS

Evidence from short-term controlled studies fails to support a benefit on muscle strength of GH replacement in GHD patients, which is likely to occur over a longer time-course, as seen in open-label studies.

Application of the disease-specific Quality of Life Assessment of Growth Hormone Deficiency in Adults (QoL-AGHDA) questionnaire in a general population: results from a French panel study

OBJECTIVES

To assess the psychometric properties of the disease-specific Quality of Life Assessment of Growth Hormone Deficiency in Adults (QoL-AGHDA) questionnaire in a general population, and collect French normative data.

METHODS

A postal survey was conducted on 2900 adult panelists representative of the French population. The participants were asked to complete a questionnaire including the QoL-AGHDA and an evaluation of their overall health status (OHS). The QoL-AGHDA score ranges from 0 to 25, a lower score indicating better QoL. Psychometric properties of the QoL-AGHDA were assessed. The mean QoL-AGHDA scores were described by sex and age groups.

RESULTS

The return rate was 75%. The quality of completion and internal consistency reliability were good: 95% of the respondents completed all 25 QoL-AGHDA items and Cronbach's alpha was 0.86. The QoL-AGHDA score was able to discriminate between the respondents according to their OHS (from 1.5 for excellent to 12.3 for poor OHS, P < 0.001). The mean QoL-AGHDA score was 4.6 for the overall population, 5.1 for females and 4.2 for males, and ranged from 4.8 for the youngest to 6.1 for the oldest respondents.

CONCLUSIONS

The QoL-AGHDA questionnaire showed good psychometric properties when administered in the French population. French reference values were collected, completing the QoL-AGHDA normative database already available in several European countries.

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.

Short- and long-term changes of quality of life in patients with acromegaly: results from a prospective study

Quality of life (QoL) may be affected in acromegalic patients, although the role of disease activity is still unsettled. The aim of the study was to assess the QoL of acromegalic patients with a specific questionnaire (ACROQOL). ACROQOL was evaluated in a prospective study (at baseline, at 6 and 24 months) in 23 active untreated acromegalic patients. Control of acromegaly was defined by normal age-matched serum IGF-I concentrations. Patient groups were defined as controlled or uncontrolled at 6 months and at 24 months: controlled or uncontrolled during the entire study period (ACRO(CC) or ACRO(NC), respectively) or uncontrolled at 6 months and controlled thereafter (ACRO(C)). At 6 months, ACROQOL scores improved globally (from 54.3+/-21 to 65.1+/-19, p=0.04) as did subdomains and were inversely related to IGF-I variation (r=-0.50, p=0.052). At 24 months, ACROQOL improved globally (from 54.3+/-21 to 65.7+/-18.0, p=0.04) and this was also seen in the appearance subdomains; however, no correlation was revealed between variation of serum IGF-I concentrations and changes in ACROQOL total score (r=0.008, p=0.87). ACROQOL scores did not significantly change in ACRO(NC) (p=0.310) and in ACRO(C) (p=0.583), whereas it improved globally (from 42.1+/-22.1 to 58.8+/-16.04, p=0.021) and in psychological subdomains in ACRO(CC); however, it reflected the improvement occurred within the first 6 months of disease control. In conclusion, successful treatment, which normalizes disease activity, improves QoL in acromegaly in the short term. However, the lack of correlation between the ACROQOL score in the long term might suggest that factors other than serum IGF-I participate in the well-being of acromegalic patients; however, due to the small sample size, our results need to be confirmed in larger studies.

Impact of GH substitution on exercise capacity and muscle strength in GH-deficient adults: a meta-analysis of blinded, placebo-controlled trials

BACKGROUND

Several but not all trials suggest that GH replacement in GH-deficient adults improves aerobic exercise capacity, whereas its effect on muscle strength is more dubious. However, a denominator of these studies is a low sample size.

OBJECTIVE

We systematically reviewed and analysed all randomized, double-blind, placebo-controlled trials on the effects of GH administration on aerobic exercise capacity and muscle strength in GH-deficient adults.

STUDY SELECTION

Fifteen trials were identified from four databases. We conducted an analysis of effects on aerobic exercise capacity, performed on either a treadmill or a bicycle ergometer, muscle strength assessed by a dynamometer, and muscle mass assessed by computerized tomography.

RESULTS

The total number of patients included was 306 and the duration of treatment ranged from 3 to 12 months. GH replacement significantly increased aerobic exercise capacity [8.9 ± 0.8%, (P < 0.001)] including VO(2) max [0.17 ± 0.02 l/min (P < 0.001)], as well as muscle volume [7.1 ± 1.6%, (P < 0.001)]. In contrast, muscle strength measured in 113 patients was not significantly increased [3.2 ± 2.2% (P = 0.15)].

CONCLUSION

GH replacement in GH-deficient adults is associated with a significant positive effect on aerobic exercise capacity and muscle mass.

Reduced cardiac functional reserve and quality of life in adults with GH deficiency

INTRODUCTION

Patients with severe GH deficiency (GHD) suffer with a reduced quality of life in addition to diverse changes in cardiac size and performance. So far, the cardiac reserve ability to maintain the circulation during peak exercise has not been measured. We tested the hypothesis that patients with severe GHD have reduced cardiac reserve function compared with healthy controls and that this could explain, in part, their reduced quality of life.

AIMS

Eighteen patients with severe GHD and an assessment of GHD in adults (AGHDA) score > or =11 (mean 20.0, range 12-25) were studied and compared with 18 age-, sex- and body mass index-matched healthy controls. Peak cardiac power and cardiorespiratory fitness were investigated using noninvasive haemodynamic measurements during maximal cardiopulmonary exercise testing.

RESULTS

Compared with matched controls, the cardiac power of GHD patients during exercise to volitional exhaustion was significantly reduced by 15% (mean +/- SD 4.4 +/- 1.0 W vs. 5.2 +/- 1.0 W, P = 0.02). Patients with GHD also had lower cardiac chronotropic reserve (peak heart rate 154 +/- 21/min vs. 174 +/- 11/min, P = 0.001) and a lower cardiac pressure-generating capacity (systolic blood pressure 160 +/- 25 mmHg vs. 200 +/- 15 mmHg, P < 0.0001). We found no correlation between any measure of peak cardiac power or function and the AGHDA score.

CONCLUSION

Using this robust noninvasive method of assessing functional cardiac pumping capacity, we have for the first time shown that, while patients with severe GHD have a significantly impaired cardiac functional reserve associated with chronotropic incompetence and impaired pressure-generating capacity, this does not correlate with their reduced quality of life assessed using the current standard AGHDA score.

The physiology of growth hormone and sport

The growth hormone (GH)/ insulin-like growth factor-I (IGF-I) axis exerts short-and long-term metabolic effects that are potentially important during exercise. Exercise is a potent stimulus to GH release and there is some evidence that the acute increase in GH is important in regulating substrate metabolism post-exercise. Regular exercise also increases 24-hour GH secretion rates, which potentially contributes to the physiologic changes induced by training. The effects of GH replacement in GH-deficient adults provide a useful model with which to study the effects of the more long-term effects of the GH/ IGF-I axis. There is convincing evidence that GH replacement increases exercise capacity. Measures of exercise performance including maximal oxygen uptake (VO2max) and ventilatory threshold (VeT) are impaired in GH deficiency and improved by GH replacement, probably through some combination of increased oxygen delivery to exercising muscle, increased fatty acid availability with glycogen sparing, increased muscle strength, improved body composition and improved thermoregulation. Administration of supraphysiologic doses of GH to athletes increases fatty acid availability and reduces oxidative protein loss particularly during exercise, and increases lean body mass. It is not known whether these effects translate to improved athletic performance, although recombinant human GH is known to be widely abused in sport. The model of acromegaly provides evidence that long-term GH excess does not result in improved performance but it is possible that a "window" exists in which the protein anabolic effects of supraphysiologic GH might be advantageous.

Growth hormone deficiency is associated with decreased quality of life in patients with prior acromegaly

CONTEXT

Both GH deficiency (GHD) and GH excess are associated with a decreased quality of life. However, it is unknown whether patients with GHD after treatment for acromegaly have a poorer quality of life than those with normal GH levels after cure of acromegaly.

OBJECTIVE

The aim of the study was to determine whether patients with GHD and prior acromegaly have a poorer quality of life than those with GH sufficiency after cure of acromegaly.

DESIGN AND SETTING

We conducted a cross-sectional study in a General Clinical Research Center.

STUDY PARTICIPANTS

Forty-five patients with prior acromegaly participated: 26 with GHD and 19 with GH sufficiency.

INTERVENTION

There were no interventions.

MAIN OUTCOME MEASURES

We evaluated quality of life, as measured by 1) the Quality of Life Adult Growth Hormone Deficiency Assessment (QoL-AGHDA); 2) the Short-Form Health Survey (SF-36); and 3) the Symptom Questionnaire.

RESULTS

Mean scores on all subscales of all questionnaires, except for the anger/hostility and anxiety subscales of the Symptom Questionnaire, showed significantly impaired quality of life in the GH-deficient group compared with the GH-sufficient group. Peak GH levels after GHRH-arginine stimulation levels were inversely associated with QoL-AGHDA scale scores (R = -0.53; P = 0.0005) and the Symptom Questionnaire Depression subscale scores (R = -0.35; P = 0.031) and positively associated with most SF-36 subscale scores.

CONCLUSIONS

Our data are the first to demonstrate a reduced quality of life in patients who develop GHD after cure of acromegaly compared to those who are GH sufficient. Further studies are warranted to determine whether GH replacement would improve quality of life for patients with GHD after cure from acromegaly.

Effects of 4 weeks recombinant human growth hormone administration on insulin resistance of skeletal muscle in rats

PURPOSE

Effect of recombinant human growth hormone (rhGH) administration on lipid storage, and its subsequent effect on insulin sensitivity have not yet been adequately examined. Thus, we investigated the effects of rhGH treatment on muscle triglyceride (TG) and ceramide content, and insulin sensitivity after 4 weeks of rhGH administration in rats.

MATERIALS AND METHODS

Fourteen rats were randomly assigned to two groups: rhGH injection group (GH, n = 7) and saline injection group (CON, n = 7). GH received rhGH by subcutaneous injections (130 microg.kg(-1).day(-1), 6 days.week(-1)) for 4 weeks, while CON received saline injections that were equivalent in volume to GH group. Intramuscular TG and ceramide content and hepatic TG content were measured. To determine insulin sensitivity, oral glucose tolerance test (OGTT) and muscle incubation for glucose transport rate were performed in rats, and used as indicators of insulin sensitivity. We also examined plasma lipid profiles.

RESULTS

After 4 weeks of rhGH treatment, the GH group had higher muscle and liver TG contents than the CON (p < 0.05). Ceramide content in GH was significantly greater than that in CON (p < 0.05). GH also had higher plasma levels of FFA (p < 0.05), glucose and insulin responses during OGTT (p < 0.05), and lower glucose transport rates in submaximal insulin concentration (p < 0.05) as compared with CON. Results indicate that rhGH treatment is associated with insulin resistance in rats.

CONCLUSION

rhGH treatment elevated muscle TG and ceramide content, and hepatic TG content. Thus, elevation of these compounded by rhGH treatment could contribute to the development of insulin resistance in rats.

Effects of short-term treadmill exercise training or growth hormone supplementation on diastolic function and exercise tolerance in old rats

Whether the lusitropic potential of short-term exercise in aged rats is linked to an augmentation in the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and an alteration in the cardiac renin angiotensin system (RAS) is unknown. Old (28-month-old) male, Fischer 344xBrown Norway rats were randomized to 4 weeks of GH supplementation (300 microg subcutaneous, twice daily) or 4 weeks of treadmill running, or were used as sedentary controls. Six-month-old rats, sedentary or exercised, were used as young controls. Training improved exercise capacity in old animals. Exercise and GH attenuated age-related declines in myocardial relaxation despite an exercise-induced suppression of IGF-1. The regulatory protein, sarcoplasmic Ca2+ adenosine triphosphatase (SERCA2), increased with exercise but not GH. Among aged rats, the cardiac RAS was not altered by training or GH. Thus, the signaling pathway underlying the lusitropic benefit of short-term habitual exercise in the aged rat may be distinct from GH-mediated benefits and independent of the cardiac RAS.

The effect of growth hormone replacement on exercise capacity in patients with GH deficiency: a metaanalysis

CONTEXT/OBJECTIVES

GH replacement in GH-deficient adults exerts clear effects on body composition, but there is a lack of high-quality evidence concerning its functional effects, which are more clinically important. This metaanalysis was carried out to determine the effects of GH replacement on exercise performance.

DESIGN/METHODS

A Medline search and examination of reference lists of included studies and relevant review articles identified 11 studies with utilizable, robust data, involving a total of 268 patients. All included studies were randomized, double blind, placebo controlled, and of either parallel or crossover design. Information was retrieved in uniform format, with data pertaining to patient numbers, study design, GH dose, age, IGF-I levels, and the exercise variables maximal oxygen uptake and maximal power output recorded. The data were analyzed using a fixed-effects model, using continuous data measured on different scales. A summary effect measure (ds) was derived for the individual exercise parameters, whereas an overall summary effect was derived from the sum of all studies across different variables; 95% confidence intervals were calculated from the weighted variances of individual study effects.

RESULTS

GH replacement was associated with significant improvement with all studies combined (ds=+0.32, 0.08-0.56), for maximal power output (ds=+0.4, 0.06-0.74), and maximal oxygen uptake (ds=+0.34, 0.07-0.62). There was no association between age or GH dose on the degree of improvement.

CONCLUSIONS

There is strong evidence that GH replacement improves exercise performance in GH-deficient patients. This evidence should be considered when decisions are made regarding prescription of GH.