Months Of GH Replacement Research Articles

Circulating Irisin Levels in Children With GH Deficiency Before and After 1 Year of GH Treatment.

To evaluate circulating irisin levels in children with GH deficiency (GHD) and any relation with clinical and metabolic parameters. Fifty-four prepubertal children (mean age, 7.4 ± 0.8 years) with idiopathic GHD treated with GH for at least 12 months and 31 healthy short children as control subjects. Body height, body mass index (BMI), waist circumference (WC), IGF-I, HbA1c, lipid profile, fasting and after-oral glucose tolerance test glucose and insulin, insulin sensitivity indices, and irisin levels were evaluated at baseline and after 12 months of GH replacement (GHR). At baseline, children with GHD, in addition to having lower growth velocity (P < 0.001), GH peak after stimulation tests (both P < 0.001), and IGF-I (P < 0.001), showed significantly lower irisin (P < 0.001) and higher BMI (P < 0.001) and WC (P = 0.001), without any difference in metabolic parameters, than control subjects. After GHR, children with GHD showed a significant increase in height (P < 0.001), growth velocity (P < 0.001), IGF-I (P < 0.001), fasting glucose (P = 0.002) and insulin (P < 0.001), homeostasis model assessment estimate of insulin resistance (P < 0.001), and irisin (P = 0.005), with a concomitant decrease in BMI (P = 0.001) and WC (P = 0.003). In multivariate analysis, the independent variables significantly associated with irisin were BMI (P = 0.002) and GH peak (P = 0.037) at baseline and BMI (P = 0.005), WC (P = 0.018), and IGF-I (P < 0.001) during GHR. We report that GHR leads to an increase in irisin levels, strongly related to a decrease in BMI and WC, and to an increase in IGF-I; these changes are among the main goals of GHR. These data confirm the favorable effects of GHR in children.

The effect of Growth Hormone replacement therapy on Lipid Metabolism in Georgian patients with Growth Hormone Deficiency

Introduction: Recently, Growth hormone deficiency (GHD) has become one of the reasons of significant metabolic and psychological morbidity in children and adults. The aim of our study was to find out the impact of GH replacement therapy on lipid profile in Georgian patients with GHD, which was caused by surgical resection. Design: Double Blind placebo controlled study for 12 months and an open study for another 12 months. Patients and Methods: 20 Georgian adults, aged 40.75±2.2 years (mean ± SE, range 20.5-60), with adult onset GH deficiency were enrolled in the study. The patients were selected from the basis of National Institute of Endocrinology. We set the inclusive and exclusive criteria to study these patients, who needed the growth hormone replacement therapy. We collected standardized information about central and peripheral hormones, metabolic activity and physical features. Results: after 12 months of GH replacement, there was no significant improvement of lipid profile in the GH deficient patients. After 24 months of the treatment, the study showed the upward trend of Triglycerides, Total cholesterol and HDL-CH, and a decrease of LDL-CH. Conclusion: The response of lipid profile to the 12 and 24 months of GH replacement in patients with GH deficiency was disappointing. The results significantly differ from the ones, provided by the European Endocrine societies. Thus, longer-term studies are required, in order to investigate accurately the whole lipid profile among our patients for the following years.

Metabolomics: a tool for the diagnosis of GH deficiency and for monitoring GH replacement?

The diagnostic value of insulin-like growth factor 1 (IGF1) for GH deficiency (GHD) in adults is not optimal. Molecular profiling could be used for biomarker discovery. The aim of this pilot study was to compare the serum metabolome between GHD patients and healthy controls, and identification of potential markers for diagnosis and/or for individual GH dosing. A total of ten patients with GHD, median age of 55 years and BMI of 27 kg/m2, were compared with ten healthy age- and gender-matched controls. The serum metabolic profiles were generated using gas chromatography-coupled mass spectroscopy on fasting samples taken in the morning from the controls and at baseline and during 6 months of GH replacement in the patients with GHD. The difference in low-molecular weight compounds (LMC) distinguished the healthy controls from GHD patients. Among 285 measured metabolites, 13 were identified as being most important in differentiating GHD patients from controls. Of these, 11 could not be structurally annotated but many were classified as lipids. The difference in the LMC pattern persisted despite normalisation of IGF1 following GH replacement. GH replacement increased the levels of specific fatty acid compounds and decreased the levels of certain amino acids. No metabolite changed in response to GH treatment, to the same extent as IGF1. The measurement of 285 metabolites resulted in a unique pattern in GHD, but changes in the metabolite patterns during GH treatment were limited. The utility of metabolomics to find new markers in GHD and GH replacement remains to be further elucidated.

Response to GH treatment in adult GH deficiency is predicted by gender, age, and IGF1 SDS but not by stimulated GH-peak

We studied whether the severity of GH deficiency (GHD) defined as i) GH-peak on stimulation tests (insulin tolerance test (ITT), arginine, and glucagon), ii) number of additional pituitary deficits, or iii) baseline IGF1 SDS could impact the response to GH treatment. We further explored whether iv) IGF1 SDS after 24 months of GH replacement or v) ΔIGF1 SDS from baseline to 24 months was related to the phenotypic response to GH treatment. DESIGN, PATIENTS, AND MEASUREMENTS: The patient cohort (n=1752; 50% women) was obtained from KIMS (Pfizer International Metabolic Database). The patients were divided into three groups of approximately equal size (tertiles) according to the stimulated GH-peak values and baseline IGF1 SDS and were studied at baseline, 12, and 24 months of GH therapy. Lower baseline IGF1 SDS predicted better response in weight, BMI, total cholesterol, and triglycerides, while IGF1 SDS after 24 months was associated with reduction in waist/hip ratio, total cholesterol, and improved quality of life (QoL). Age-correlated negatively with the response in body weight, BMI, waist, IGF1 SDS, and total and LDL-cholesterol. Response in weight and BMI was greater in men than in women, whereas women showed greater improvement in QoL than men. Patients with more severe GHD as assessed by lower GH-peaks and more pituitary hormone deficiencies had a greater increase in IGF1 SDS. The increase in IGF1 SDS was associated with a reduction in waist/hip ratio and an increase in weight, BMI, and triglycerides. There was no correlation with other lipids, blood pressure, or glucose. Our findings indicate that baseline and 24 months, IGF1 and its degree of increase during GH replacement were more important than stimulated peak GH to predict the phenotypic response.

Hepatic steatosis, GH deficiency and the effects of GH replacement: a Liverpool magnetic resonance spectroscopy study

Non-alcoholic fatty liver disease (NAFLD) is reported to be more common in patients with GH deficiency (GHD) than in the general population. we aimed to determine: i) liver fat in patients with GHD compared with age and body mass index (BMI)-matched controls; and ii) effect of 6 months of GH replacement (GHR) on liver fat. The study included 28 GHD patients and 24 controls. 12 patients were studied before and after 6 months of GHR. Anthropometry, liver enzymes and lipid profiles were measured, and body composition and intrahepatocellular lipid (IHCL) were determined by magnetic resonance imaging and spectroscopy. Age and BMI (median (inter-quartile range)) of patients and controls were 52.6 (14) vs 52.6 (12) years (P=0.9) and 27.8 (24.7, 34.7) vs 27.9 (25.1, 32.1) kg/m(2) (P=0.9). IGF1 was lower in the patients (11.5 vs 16.0 nmol/l, P=0.002). There was no difference in liver transaminases, lipids or IHCL between patients and controls (2.8 (1.3, 8.6) vs 5.0 (1.5, 12.7), P=0.72), despite significantly higher visceral fat in GHD patients. Thirty-two percent of patients and 50% of controls had NAFLD (defined as IHCL >5.6%), and the relationship between IHCL and BMI was the same in each group. GHR significantly reduced abdominal subcutaneous and visceral fat in all patients; however, GHR did not reduce liver fat. NAFLD is equally common in patients with GHD and matched controls. GHR is associated with a hierarchical reduction in fat deposition (fat loss: visceral > subcutaneous > liver). Further studies involving GHD patients with NAFLD are required to conclude the role of GHR in treating NAFLD.

Health-related quality of life and IGF-1 in GH-deficient adult patients on GH replacement therapy: analysis of the German KIMS data and the Study of Health in Pomerania

To analyse 12-month response to GH treatment in a single-country cohort of hypopituitary adult patients with GH deficiency (GHD) in regards to health-related quality of life (HRQoL) and insulin-like growth factor-1 (IGF-1) compared with values from general population sample. Moreover, association between the response in HRQoL and the IGF-1 values in patients and in the background population was investigated. HRQoL was assessed by quality of life assessment of GH deficiency in adults (QoL-AGHDA) in 651 patients retrieved from the German KIMS (Pfizer International Metabolic Database) before and after 12 months of GH replacement and in a sample drawn from a cross-sectional study in Germany (n=2734). IGF-1 was measured in KIMS patients and in the population-based study with the same assay technique. In KIMS patients, mean QoL-AGHDA scores before GH replacement were 9.2+/-6.8 (8.7+/-6.8) in women (men) and in the general population sample 4.5+/-5.3 (4.3+/-5.0) in women (men). Mean differences in QoL-AGHDA scores were statistically significant for all age categories (P<0.05). The mean IGF-1 SDS of KIMS patients before GH replacement was -1.1+/-1.4 (-0.8+/-1.4) in women (men). After GH replacement, a significant increase of IGF-1 concentration and a significant decrease of QoL-AGHDA scores near to age- and gender-specific population-based values were observed. This study confirms an improvement in HRQoL and an increase of IGF-1 SDS in GH-replaced adults, which approximated the values of general population. However, there was no association between IGF-1 values and HRQoL assessment as one of the important treatment outcomes.

GH replacement reduces increased lipid peroxidation in GH‐deficient adults

GH replacement improves numerous metabolic abnormalities in GH-deficient patients; increased lipid peroxidation (LPO) has been observed in GH-deficient patients; however, it is unknown if LPO is influenced by GH replacement. To evaluate the extent to which GH replacement might reverse the increased LPO in GH-deficient adults and to analyse if this phenomenon might be involved in the improvement of metabolic disturbances due to GH treatment. Serum concentrations of malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA), as an index of LPO, were measured at baseline, and after 12 and 24 months of GH replacement in 40 adult patients with severe GH deficiency (both in adult- and childhood-onset) and in 40 healthy volunteers, matched for sex, age and body mass index (BMI). Correlations were evaluated between LPO and lipids, IGF-I, metalloproteinase-2 and -9 (MMP-2, -9), vascular endothelial growth factor (VEGF), BMI and GH dose. LPO values in GH-deficient patients were several-fold higher than in controls [55.36 +/- 2.27 vs. 4.19 +/- 0.42 nmol/mg protein (mean +/- SEM), P < 0.0001] and decreased significantly over time with GH replacement to 38.61 +/- 2.15 nmol/mg protein (i.e. by approximately 30%), though still remaining markedly elevated compared with controls (P < 0.0001). The proatherogenic lipid profile parameters correlated positively with LPO in the childhood-onset subgroup before GH replacement. GH replacement restored the positive correlation between LPO and age in male patients (r = 0.57, P = 0.013; r = 0.8, P < 0.001, at 12 and 24 months of GH replacement, respectively). GH replacement partially reverses the grossly abnormal LPO in GH-deficient adults. It is highly probable, therefore, that oxidative mechanisms are involved in the overall improvement of metabolic changes due to GH replacement.

Growth Hormone Replacement Therapy in Adults with Growth Hormone Deficiency Improves Maximal Oxygen Consumption Independently of Dosing Regimen or Physical Activity

Several studies have demonstrated an improvement in aerobic exercise capacity with 6 months of GH replacement in adults with GH deficiency (GHD). The objective of the study was to determine whether improvements in aerobic exercise capacity with GH treatment in adults with GHD are related to changes in physical activity or affected by the GH dosing regimen. This was a randomized, two-arm, parallel, open-label study. The study was conducted at five academic medical centers with exercise physiology laboratories. Study subjects were adults (n = 29) with GHD due to hypothalamic-pituitary disease. The intervention was GH replacement therapy, administered either as a fixed body weight-based dosing regimen as an individualized dose titration regimen for 32 wk. Maximal oxygen consumption (VO2 max) and oxygen consumption (VO2) at the lactate threshold, ventilatory threshold using a cycle ergometry protocol, and weekly energy expenditure (physical activity questionnaire), assessed at baseline and end point, were measured. In the group as a whole, VO2 max increased significantly (by 9%) from baseline (19.1+/- 0.89 ml/kg.min) to end point (21.6 +/- 1.23 ml/kg.min, P = 0.010). Compared with baseline, VO2 max also changed significantly within the individualized dose titration regimen group (+2.5 +/- 0.98 ml/kg.min, P =0.034) but not within the fixed body weight-based dosing regimen group (+1.2 +/- 0.78 ml/kg.min, P = 0.15), although these changes from baseline were not significantly different between the two groups. VO2 at lactate threshold, VO2 at ventilatory threshold, and weekly energy expenditure also did not change. GH replacement therapy in GH-deficient adults improved VO2 max similarly with both dosing regimens, without any influence of physical activity. There was no effect on submaximal exercise performance.

Two years of growth hormone replacement therapy in a group of patients with Sheehan’s syndrome

To investigate the effects of GH replacement on lipid profile, carotid artery intima-media thickness (IMT), glucose metabolism and visceral fat in patients with Sheehan's syndrome, ten patients, mean age 44.8+/-9.5 yr, compared with 10 controls matched for age and body mass index were studied. Total cholesterol, Triglycerides (TG), HDL-c, LDL-c, Apolipoprotein A and B (apoA and apoB) and Lipoprotein (a), serum IGF-1, ultrasonography of the carotid arteries, oral glucose tolerance test (OGTT), HOMA insulin resistance index, insulin sensitivity index (ISI)-composite and abdominal CT scan were performed. When compared to a control group, patients presented lower HDL concentrations (p=0.05) and 2-h OGTT insulin levels (p<0.04) and increased TG levels (p<0.04). After 24 months of GH replacement a reduction in the relation ApoB/ApoA (p=0.04) was observed, as well as an increase in HDL (p<0.004). A decrease in carotid artery IMT and in visceral fat over time was found, p<0.03 and p<0.04 respectively, though without any significant differences during post hoc comparisons of means, which may be explained by the small number of cases studied, but there was a tendency, p=0.08 and p=0.09 respectively. The 2-h OGTT insulin levels increased (p<0.02) as well as the prevalence of glucose intolerance (prevalence = 42.8%, p<0.05). GH replacement therapy promoted favorable effects on carotid artery IMT, lipid profile and visceral fat in patients with Sheehan's syndrome. On the other hand, patients developed abnormal glucose tolerance probably due to an increase in insulin resistance, demonstrated by higher insulin levels, despite favorable changes in body composition.

Body composition during GH replacement in adults – methodological variations with respect to gender

Men with growth hormone deficiency (GHD) may be more sensitive to GH treatment than women in terms of changes in body composition. We have studied whether age, body-mass index (BMI) and the different types of methodology used to assess body composition may explain these differences. Forty-four men and forty-four women with GHD, closely matched for age and BMI, were studied before and after 6 months of GH replacement. The dose of GH was individually adjusted. Body composition was assessed by measurements of potassium-40, total body nitrogen (TBN), tritiated water dilution, dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). Four- and five-compartment models for body composition were also calculated. The total daily dose of GH was similar in men and women at 6 months. Serum insulin-like growth factor-I (IGF-I) was higher in men than women at baseline and after 6 months of treatment (P = 0.01, paired t-test). The increment was, however, similar. In women, GH treatment reduced body weight and increased TBN. In both men and women, total body water and body cell mass increased, while total body fat (BF) mass decreased. At baseline, mean total BF varied considerably depending on the methodology used, with the highest value obtained from DXA. The changes in BF were, however, less dependent on the methodology, but DXA and BIA demonstrated the largest inconsistency between men and women. These results suggest that gender differences in body composition in response to GH treatment are small, if adjustments are made for baseline factors such as age, BMI and dose of GH. Different methods of body composition measurements produce different results, but changes in response to GH administration are less inconsistent.

Interdependence of lean body mass and total body water, but not quality of life measures, during low dose GH replacement in GH-deficient adults

Lean body mass (LBM) and total body water (TBW) are reduced in GH-deficient (GHD) adults and alter with GH replacement. Whether these parameters are interdependent and whether alterations in their homeostasis contribute to the perceived quality of life (QOL) deficit in GHD remains unclear. In this study, IGF-I, body composition by whole-body dual-energy X-ray absorptiometry, TBW by deuterium dilution (D(2)O) and two validated QOL instruments - psychological general well-being schedule (PGWB, generic, 6 domains; lower score worse QOL) and assessment of GH deficiency in adults (AGHDA, disease orientated; higher score worse QOL) were studied at baseline and after 3 and 6 months of GH replacement in thirty GHD adults. Patients with diabetes insipidus, and cardiac and renal failure were excluded. Median age-adjusted IGF-I standard deviation score increased from -3.40 (-6.40 to -1.60) to -0.2 (-1.88 to 0.78) (P < 0.0001) at a median daily GH dose of 0.4 mg. During treatment, LBM increased from 47.4 +/- 10.7 kg at baseline to 49.5 +/- 10.8 kg at 6 months (P = 0.0008), and fat mass decreased from 28.0 +/- 12.1 kg at baseline to 27.2 +/- 12.6 kg at 6 months (P = 0.0004). A non-significant trend towards an increase in TBW was observed (mean 1.7 kg, P = 0.08). The PGWB score increased from 62.9 +/- 20.6 to 73.7 +/- 21.7 (P = 0.0006). The AGHDA score decreased from 13.7 +/- 7.3 to 8.75 +/- 7.75 (P = 0.0002). At each time point, a linear correlation between LBM and TBW was demonstrated, defined by TBW = (0.972 x LBM)-10.6. However, only a weakly positive correlation existed between the percentage changes in these variables (R = 0.40, P = 0.04). No correlations were demonstrated between QOL measures and body composition. The change in LBM with physiological GH replacement correlates weakly with change in TBW, therefore factors other than TBW may also contribute to the LBM changes. Improved QOL with GH replacement is not explained by favourable changes in body composition.

Left ventricular mass and function in children with GH deficiency before and during 12 months GH replacement therapy.

This open, prospective study was designed to evaluate the effect of GH deficiency (GHD) on left ventricular (LV) mass (LVM) and performance, by echocardiography, and on lipid profile during childhood. Twelve prepubertal children with GHD (eight boys and four girls) aged 8.1 +/- 1.7 years were studied before and after 6 and 12 months of GH replacement therapy at a dose of GH of 30 micro g/kg/day. Twelve healthy children sex-, height-, weight- and body surface area-matched with the patients, served as controls. Echocardiography was performed at study entry and after 12 months both in GHD children and in controls. Only in GHD children, echocardiography was repeated also after 6 months of GH replacement. In all subjects, we measured LV posterior wall thickness (LVPWT), LV end-diastolic diameter (LVEDD), LVM index (LVMi), LV systolic and diastolic function. At study entry, LVPWT (5.3 +/- 0.8 vs. 6.2 +/- 1.1 mm, P < 0.05), LVEDD (34.0 +/- 2.4 vs. 36.7 +/- 2.1 mm, P < 0.007) and LVMi (47.0 +/- 6.9 vs. 59.6 +/- 9.5 g/m2, P < 0.005) were significantly lower in GHD children than in controls. Lipid profile, heart rate, blood pressure, LV systolic function and indices of ventricular filling were similar in patients and controls. After 12 months of GH replacement therapy, LVPWT (6.1 +/- 0.7 mm, P < 0.0005), LVEDD (38.8 +/- 4.3 mm, P < 0.002) and LVMi (71.5 +/- 12.7 g/m2, P < 0.0005) significantly increased in GHD children compared to pretreatment values. In particular, after 12 months of therapy GHD children achieved a normal LVMi when compared to controls (60.7 +/- 8.6, P = ns). LVMi increase was significantly correlated with the increase in IGF-I level (r = 0.49; P < 0.004). LV systolic performance, diastolic filling and blood pressure did not change significantly during GH therapy. After 12 months of treatment, the atherogenic index, measured as total/high-density lipoprotein-cholesterol ratio (2.7 +/- 0.8) was significantly lower than both pretreatment (3.4 +/- 0.3, P < 0.03) and control values (3.8 +/- 1.1, P < 0.04). GH deficiency in children affects heart morphology, by inducing a significant decrease in cardiac size, but does not modify cardiac function and lipid profile. Twelve months of GH replacement treatment normalizes cardiac mass, and reduces the atherogenic index.

Effects of growth hormone replacement on parathyroid hormone sensitivity and bone mineral metabolism.

Adult GH deficiency (AGHD) is associated with reduced bone mineral density, and decreased end-organ sensitivity to the effects of PTH has been suggested as a possible underlying mechanism. We investigated the effects of GH replacement (GHR) on PTH circulating activity and its association with phosphocalcium metabolism and bone turnover in 16 (8 men and 8 women) AGHD patients. Half-hourly blood and 3 hourly urine sampling was performed on each patient over a 24-h period before GHR and then after 1, 3, 6, and 12 months of GHR. GH was commenced at a dose of 0.5 IU/d and was titrated to achieve and maintain an IGF-I SD score within 2 SD of the age-related reference range. The target IGF-I SD score was achieved within 3 months and was maintained at 12 months after GHR in all patients. Our results demonstrated a significant decrease in serum PTH at all visits after GHR compared with baseline values (P < 0.001), with a concomitant increase in nephrogenous cAMP excretion at 1 (P < 0.001) and 3 (P < 0.05) months and increases in serum calcium (P < 0.001), serum phosphate (P < 0.001), 1,25-dihydroxyvitamin D(3) (P < 0.001), type I collagen C-telopeptide (a bone resorption marker; P < 0.001), and procollagen type I amino-terminal propeptide (a bone formation marker; P < 0.001). Simultaneously, we observed a significant decrease in urinary calcium excretion (P < 0.001) and an increase in maximum tubular phosphate reabsorption (P < 0.001). Together these results suggest increased end-organ responsiveness to the effects of circulating PTH resulting in increased bone turnover and reduced calcium excretion. Significant circadian rhythms were observed for serum PTH, phosphate, type I collagen C-telopeptide, and procollagen type I amino-terminal propeptide before and after GHR. However, sustained PTH secretion was observed between 1400-2200 h, with a reduced nocturnal rise in untreated AGHD patients, whereas PTH secretion decreased significantly between 1400-2200 h (P < 0.001), with a significant increase in nocturnal PTH secretion (P < 0.001) after 12 months of GHR. Our results demonstrate that GH may have a regulatory role in bone mineral metabolism, and our data provide a possible underlying mechanism for the development of osteoporosis in AGHD patients. The changes observed after GHR may further explain the beneficial effects of GHR on bone mineral density that have consistently been reported.

The effect of growth hormone replacement therapy on adrenal androgen secretion in adult onset hypopituitarism.

Growth hormone replacement therapy in GH-deficient children is associated with enhanced adrenal androgen production, raising the possibility that GH might stimulate adrenocortical hormone secretion. This has not been extensively investigated in adults to date. GH is a potent modulator of the activity of the 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) enzyme and by altering cortisol metabolism can affect the function of the hypothalamo-pituitary-adrenal (HPA) axis and therefore potentially of adrenal androgen secretion. This study examined the effects of GH replacement in GH-deficient adults on adrenal androgen secretion. Prospective study of the effect of GH replacement therapy on adrenal androgen production in patients with adult onset hypopituitarism over a 12-month period. Thirty adult GH-deficient patients were classified into two groups according to their cortisol responses to an insulin-induced hypoglycaemia or a glucagon stimulation test: 13 patients were adrenocorticotropic hormone (ACTH)-sufficient (nine females, age 45.1 +/- 3 years), whereas 17 patients were ACTH-deficient (11 females, age 45.5 +/- 3 years). Serum samples were collected before patients were initiated on GH replacement therapy using a dose titration regimen, and after 6 and 12 months on GH therapy for measurement of serum IGF-I, dehydroepiand-rosterone sulphate (DHEAS), Delta4-Androstenedione (A4), testosterone, cortisol, sex hormone binding globulin (SHBG) and cortisol binding globulin (CBG). Six months after the initiation of GH replacement therapy, serum IGF-I levels were within the normal age-related reference range in both groups of patients and this was maintained at 12 months [in all patients 0 vs. 6 months: median (interquartile range): 92.5 ng/ml (73-116 ng/ml) vs. 191 ng/ml (159-224 ng/ml), P < 0.01]. In both ACTH-sufficient and -deficient groups of GH-deficient patients, pretreatment serum DHEAS levels were lower than the normal age-related reference range (P < 0.01); the ACTH-deficient patients had significantly lower DHEAS levels than the ACTH-sufficient patients [median (interquartile range): 0.5 micro mol/l (0.4-1.2 micro mol/l) vs. 1.5 micro mol/l (0.6-2.7 micro mol/l), P < 0.05]. Following GH replacement therapy, median levels of serum DHEAS levels rose from 1.5 micro mol/l (0.6-2.7 micro mol/l) to 1.9 micro mol/l (1.9-3.9 micro mol/l) in ACTH-sufficient patients, increasing in 11 of the 13 patients (P < 0.02). In this group, the median percentage increase from baseline was 32% at 6 months (P < 0.05). In contrast, baseline serum DHEAS levels [0.5 micro mol/l (0.4-1.2 micro mol/l)] declined in or from the measurable range in 47% of ACTH-deficient patients [median -16%; range -36-0] and only in one patient a + 0.2 micro mol/l increase was observed. GH dose requirements tended to be lower in ACTH-sufficient patients [1.2 U/day (0.8-1.4 U/day) vs. 1.6 U/day (1.0-2.0 U/day); P = 0.062]. There were no significant changes in serum testosterone, A4, SHBG and/or CBG levels, compared to the pretreatment levels, in either group of patients over the 12 months of GH replacement. This study shows that median serum DHEAS levels are significantly lower in GH-deficient patients, even those with intact ACTH reserve, than in aged-matched controls. GH replacement therapy is associated with a significant increase in mean serum DHEAS only in ACTH-sufficient patients. These findings are consistent with either (i) GH stimulation of adrenal androgen production in the permissive presence of ACTH or (ii) an inhibitory effect of GH on 11beta-HSD type 1 activity leading to enhanced cortisol clearance, subsequent activation of the HPA axis and ACTH-mediated androgen secretion.

The cardiovascular risk of adult GH deficiency (GHD) improved after GH replacement and worsened in untreated GHD: a 12-month prospective study.

Increased cardiovascular morbidity and mortality were reported in GH deficiency (GHD), and GH replacement can ameliorate cardiac abnormalities of adult GHD patients. To test the potential progression of untreated GHD on the cardiovascular risk and cardiac function, cardiovascular risk factors, cardiac size, and performance were prospectively evaluated in 15 GHD patients (age, 18-56 yr) who were treated with recombinant GH at the dose of 0.15-1.0 mg/d, 15 GHD patients (age, 18-56 yr) who refused GH replacement, and 30 healthy subjects (age, 18-53 yr). Electrocardiogram, systolic and diastolic blood pressure, and heart rate measurement, serum IGF-I, total cholesterol, low- and high-density lipoprotein (LDL, HDL) cholesterol, triglycerides, and fibrinogen level assay, echocardiography, and equilibrium radionuclide angiography were performed basally and after 12 months. At study entry, low IGF-I levels, unfavorable lipid profile, and inadequate cardiac and physical performance were found in GHD patients compared with controls. After 12 months of GH treatment, IGF-I levels normalized; HDL-cholesterol levels, left ventricular (LV) mass index (LVMi), left ventricular ejection fraction (LVEF) at peak exercise, peak filling rate, exercise duration and capacity significantly increased; total- and LDL-cholesterol levels significantly decreased. After 12 months in GH-untreated GHD patients, IGF-I levels remained stable, and HDL-cholesterol levels, LVEF both at rest and at peak exercise, and exercise capacity were further reduced; total- and LDL-cholesterol levels increased slightly. LVEF at rest and its response at peak exercise normalized in 60 and 53.3%, respectively, of GH-treated patients and in none of the GH-untreated patients. In conclusion, 12 months of GH replacement normalized IGF-I and improved lipid profile and cardiac performance in adult GHD patients. A similar period of GH deprivation induced a further impairment of lipid profile and cardiac performance. This finding strongly supports the need of GH replacement in adult GHD patients.

GH-deficient survivors of childhood cancer: GH replacement during adult life.

Childhood survivors of cancer are prone to a number of adverse sequelae related to the therapeutic interventions undertaken to achieve remission. The endocrine system is frequently affected; hypothalamo-pituitary dysfunction, in particular GH deficiency, is common after cranial irradiation. It is unclear to what extent GH deficiency contributes to the abnormalities observed in adult survivors of childhood cancer, and whether GH replacement reverses these anomalies. We compared 27 GH-deficient survivors of childhood cancer with 27 adult age- and sex-matched controls and went on to replace GH in the patient group to determine whether GH resulted in improvements of the baseline abnormalities. The GH-deficient survivors of childhood cancer had an adverse lipid profile (total cholesterol, 5.4 vs. 4.6 mM, P = 0.004; high-density lipoprotein cholesterol, 1.05 vs. 1.6 mM, P < 0.001; and triglycerides, 1.3 vs. 1.0 mM, P < 0.001) and were osteopenic (lumbar spine z-score, -1.53 vs. -0.31 SD score, P < 0.001; femoral neck z-score, -1.23 vs. -0.27 SD score, P = 0.02); additionally, the female subgroup had an increased percentage body fat (43.6 vs. 32.8%, P = 0.016). In keeping with the selection criterion, quality of life in the patient cohort, relative to the healthy controls, was severely impaired [adult GH-deficiency assessment (AGHDA), 15.5 (range, 8-25) vs. 1 (range, 0-19), P < 0.0001; psychological general well-being schedule, 67.5 (range, 18-86) vs. 89.0 (range, 51-104), P < 0.0001]. After 12 months of GH replacement, small (but significant) improvements were observed in body composition in the male subgroup (waist-hip ratio, 0.871 vs. 0.863, P < 0.05); and in the female cohort, total cholesterol (6.0 vs. 5.2 mM, P = 0.01) and triglyceride (2.1 vs. 1.4 mM, P = 0.01) levels fell. Bone mineral density improved in only one of the four sites studied (ultradistal radius, -1.21 vs. -1.09, P = 0.048) after a median duration of GH therapy of 18 months. Quality of life improved dramatically by 3 months (AGHDA, 15.5 vs. 10.0, P < 0.001), and the improvement was maintained at 12 months (AGHDA, 15.5 vs. 9.0, P < 0.001). Importantly, there was no clinical suggestion of tumor recurrence during the 12 months of GH replacement. The minor improvements observed in body composition, the lipid profile, and bone mineral density in GH-deficient adult survivors of childhood cancer after 12-18 months of physiological GH replacement suggest that GH deficiency may not be the major etiological factor in their pathogenesis; the converse seems to be true for the quality of life status of these individuals. We propose that, as in patients with hypopituitarism caused by pituitary disease, the main indication for GH replacement in GH-deficient survivors of childhood cancer should be severe impairment of quality of life.

The effect of GH replacement therapy on endothelial function and oxidative stress in adult growth hormone deficiency.

Controversy persists with regard to the atherogenic risk associated with adult growth hormone deficiency (GHD). Endothelial dysfunction and enhanced oxidative stress are early features of atherogenesis. Therefore, we have studied the effect of three months of low dose GH replacement therapy (0.03IU/kg/day) on these parameters in GHD adults. Eight hypopituitary GHD adults (4 male, 4 female), who were receiving conventional hormone replacement therapy, were studied before and after 3 months of GH replacement (0.03IU/kg/day). All observations obtained were compared with similar measurements made in 8 matched control subjects. All study subjects were non-smokers, normotensive and gave no personal or family history of premature vascular disease. Endothelial function was assessed using a specialised vessel wall tracking system to measure endothelium-dependent, flow-mediated, brachial artery dilatation (FMD). Measurements were repeated following glyceryl-trinitrate (GTN) (endothelium-independent dilatation). Oxidative stress was assessed by directly measuring lipid-derived free radicals in venous blood by electron paramagnetic resonance spectroscopy. Fasting lipids, insulin, plasma glucose and IGF-I were also measured at baseline and following GH replacement. FMD, expressed as a percentage change from resting base-line diameter, was significantly impaired in the pre-treatment GHD patients compared with controls (3.1+/-2.1% vs 6.1+/-0.9%, P<0. 001; means+/-s.d.) indicating endothelial dysfunction. Significant increase in FMD was noted following GH therapy (3.1+/-2.1% vs 6. 5+/-1.9%, P<0.001). Free radicals (arbitrary units) were elevated in the pre-treatment GHD patients compared with controls (0.36+/-0.09 vs 0.11+/-0.12, P<0.05) and fell significantly following GH therapy (0.23+/-0.03 vs 0.36+/-0.09, P<0.05), although they remained elevated compared with controls. Fasting insulin was significantly higher (25.9+/-18.8 vs 13.9+/-6.7mu/l, P<0.05) and IGF-I concentrations lower (10.8+/-4.7 vs 20.2+/-6.3nmol/l, P<0.05) in the pre-treatment GHD subjects. After treatment there were no changes in insulin concentration, although IGF-I levels were normalised (10. 8+/-2.3 vs 23.6+/-11.4nmol/l, P<0.05). Endothelial dysfunction and enhanced oxidative stress are features of adult GHD. This study suggests plausible mechanisms underlying any proatherogenic tendency in adult GHD and demonstrates improvement of these factors following GH replacement.

Further increase in forearm cortical bone mineral content after discontinuation of growth hormone replacement

Growth hormone replacement of adults with childhood onset GH deficiency results in an increase in bone mineral density (BMD) after 6-12 months of GH replacement. By measuring BMD 12 months after discontinuation of GH replacement we aimed to investigate whether there is an effect of GH replacement on BMD persisting after GH has been withdrawn. BMD was measured 13 +/- 1 (mean +/- SE, range 11-16) months after discontinuation of GH replacement. Ten adults, age 23.2 +/- 1.4 (range 18.8-32.4) years, with childhood onset isolated GH deficiency (2 idiopathic, 8 irradiation induced) who had previously completed a study of the effect of 12 months of GH replacement on BMD. Forearm cortical bone mineral content (BMC) was measured using single-photon absorptiometry at the proximal site of the distal forearm. Forearm integral BMC at the ultradistal site of the forearm and bone width at both proximal and ultradistal sites of the distal forearm were measured by the same technique. Vertebral trabecular BMD was measured using quantitative computed tomography. Forearm cortical BMC was significantly greater than that measured at the time of discontinuation of GH (1.48 +/- 0.04 vs 1.44 +/- 0.05 g/cm). There was no significant change in forearm integral BMC or in vertebral trabecular BMD after discontinuation of GH. There was no significant change in bone width at proximal and ultradistal sites of the distal forearm after discontinuation of GH. After discontinuation of GH replacement the further increase in forearm cortical bone mineral content without a significant increase in forearm bone width suggests that the increase in cortical bone mineral content is due to a persisting effect of previous GH replacement, and not to further spontaneous attainment of bone mass before peak bone mass is reached. These findings emphasize the importance of continuing to monitor bone mass after the stimulus to increase bone turnover has been withdrawn.