Serum GH Levels Research Articles

MON-464 Non-Clinical Profiling of ONO-5788, a Novel Oral Small Molecule Somatostatin Receptor Type-2 (SST2) Agonist, to Support Studies in Humans

Somatostatin analogues (SSAs) are indicated for use in acromegaly and gastroenteropancreatic neuroendocrine tumors (GEP NETs). However, SSAs are administered as injections which can be a challenge for patients and healthcare providers. ONO-5788 is a novel low molecular weight orally administered molecule with potent and selective agonistic effects at the human SST2 subtype. ONO-5788 could offer the advantages of a more convenient route of administration for patients with acromegaly and other indications and also a preferential safety profile compared to injections. In order to support clinical evaluation of ONO-5788, a series of non-clinical experiments were undertaken. Findings: In vitro, ONO-5788 and its active metabolite, ONO-ST1-641, has a greater agonistic effect on human SST2 compared to other somatostatin receptor subtypes, with EC50 values of 0.11 and 0.016 nmol/L, respectively. There is no difference in mean EC50 values between human SST2 and rat SST2. ONO-5788 and ONO-ST1-641 significantly inhibits growth hormone-releasing hormone (GHRH)-induced GH secretion from primary cultured rat pituitary cells. In vivo studies in rats confirmed that a single oral dose of ONO-5788 resulted in systemic exposure of ONO-5788 and ONO-ST1-641 that increased in a dose dependent manner. Orally administrated ONO-5788 significantly inhibited both GHRH-induced GH secretion and basal GH secretion at all the doses tested (≥0.1 and ≥0.03 mg/kg, respectively). ONO-5788 and ONO-ST1-641 administrated intravenously significantly inhibited GHRH-induced GH secretion with effect on maximum inhibition of GH secretion similar to octreotide (ONO-5788 98.0%, ONO-ST1-641 98.6%, octreotide 98.7%, respectively). Plasma concentrations of ONO-5788 and ONO-ST1-641 required to supress serum GH level to a clinically meaningful degree in acromegaly patients were estimated to be 21.3 and 1.29 ng/mL. In experiments evaluating the effects on insulin and glucagon secretion in anaesthetised rats, ONO-5788, ONO-ST1-641, octreotide and pasireotide significantly inhibited glucagon secretion, but ONO-5788 and ONO-ST1-641 had no significant impact on insulin secretion at doses up to 10-fold higher than the dose required for either of these compounds to almost maximally inhibit GH secretion. In contrast, pasireotide and octreotide showed a significant inhibition of insulin secretion at equivalent doses of both ONO-5788 and ONO-ST1-641. A standard battery of preclinical safety and toxicology studies provided adequate evidence of safety to support commencement of a Phase I study in healthy volunteers to measure the safety, pharmacokinetics, and pharmacodynamics of ONO-5788. Conclusion: Orally administered ONO-5788 demonstrates potency as a SST2 agonist and has the potential to be a new treatment option for patients with acromegaly and NET.

Circulating aryl hydrocarbon receptor-interacting protein (AIP) is independent of GH secretion.

BackgroundAryl hydrocarbon receptor-interacting protein (AIP) is evolutionarily conserved and expressed widely throughout the organism. Loss-of-function AIP mutations predispose to young-onset pituitary adenomas. AIP co-localizes with growth hormone in normal and tumorous somatotroph secretory vesicles. AIP protein is detectable in circulation. We aimed to investigate possible AIP and GH co-secretion, by studying serum AIP and GH levels at baseline and after GH stimulation or suppression, in GH deficiency (GHD) and in acromegaly patients.Subjects and methodsInsulin tolerance test (ITT) was performed in GHD patients (n = 13) and age-BMI-matched normal GH axis control patients (n = 31). Oral glucose tolerance test (OGTT) was performed in active acromegaly patients (n = 26) and age-BMI-matched normal GH axis control patients (n = 18). In-house immunometric assay was developed for measuring circulating AIP.ResultsSerum AIP levels were in the 0.1 ng/mL range independently of gender, age or BMI. Baseline AIP did not differ between GHD and non-GHD or between acromegaly and patients with no acromegaly. There was no change in peak, trough or area under the curve during OGTT or ITT. Serum AIP did not correlate with GH during ITT or OGTT.ConclusionsHuman circulating serum AIP in vivo was assessed by a novel immunometric assay. AIP levels were independent of age, sex or BMI and unaffected by hypoglycaemia or hyperglycaemia. Despite co-localization in secretory vesicles, AIP and GH did not correlate at baseline or during GH stimulation or suppression tests. A platform of reliable serum AIP measurement is established for further research of its circulatory source, role and impact.

Soluble delta-like 1 homolog decreases in patients with acromegaly following pituitary surgery: A potential mediator of adipogenesis suppression by growth hormone?

ObjectiveGH excess in acromegaly leads to lower fat mass and insulin resistance; both reverse following pituitary surgery. Soluble delta like-1 homolog (sDlk1) inhibits adipocyte differentiation and may mediate the antiadipogenic effects of GH. It is released into the circulation by ectodomain shedding through ‘A Disintegrin And Metalloproteinase domain 17’ (ADAM17), which also sheds soluble α-Klotho (sKlotho). Klotho is a transmembrane protein, which influences life span. sKlotho inhibits insulin signalling, and is markedly elevated in acromegaly and decreases after surgery. Therefore, we examined if sDlk1 parallels the course of sKlotho, which could explain the well-known changes in fat mass in patients with acromegaly after surgery. DesignWe measured serum levels of GH, IGF-1, sDlk1 and sKlotho (both by ELISA) in 42 treatment-naïve acromegaly patients (20 females/22 males) before and 1–3 months after transsphenoidal surgery. Data are presented as median(interquartile range). ResultsGH decreased in all patients postoperatively (in 32/42 to <1 ng/ml during oral glucose tolerance testing). Likewise, IGF-1 and sKlotho decreased in all patients, from 587 (432–708) to 195 (133–270) ng/ml, and from 4.0 (2.7–5.9) to 0.7 (0.6–1.2) ng/ml, respectively; sDlk1 fell in 40/42 subjects, from 10.7 (5.8–13.4) to 7.1 (3.7–10.4) ng/ml following pituitary surgery. P < 0.0001 for all parameters. ConclusionssDlk1 declined after pituitary surgery in our patients with acromegaly, but to a lesser extent than sKlotho. It remains to be seen whether this may contribute to the well-known postoperative changes in body composition. Our findings may extend beyond the scope of acromegaly, and thus further elucidate mechanisms in the fields of obesity and anti-ageing.

Respiratory Disorders in Acromegalic Patients

Purpose: To evaluate the prevalence and clinical performance of obstructive sleep apnoea syndrome (OSAS) in acromegalic patients, focusing on the possible correlation between alterations of pulmonary microcirculation and patient’s clinical and hormonal parameters. Methods: We enrolled 22 acromegalic patients with apnea hypopnea index (AHI) ≥ 5 if symptomatic, or ≥15 in the absence of sleep related symptoms. Patients underwent the following evaluations: GH and IGF-1 serum levels, arterial blood gas test, spirometry, carbon monoxide diffusing capacity (DLCO), home-based cardiorespiratory sleep and pulmonary function test. Results: The prevalence of OSAS was 66.6%. Patients with a severe form of OSAS appeared to be affected from acromegaly for more years than those with a lower severity of disease and those with acromegaly duration > 10 years had significantly higher levels of glycated hemoglobin. We observed a positive correlation between GH level at diagnosis and DLCO value, showing that acromegalic patients have an increase in static and dynamic respiratory volumes and alveolar-capillary exchange surface compared to the general population. We also observed a positive correlation between baseline serum IGF-1 level and DLCO/VA and between years of disease and DLCO/VA, showing the association of increased lung volume and increase of the exchange surface. Conclusions: The results of this study add new information on lung volume and alveolar gas exchange in acromegaly. Our findings highlight the role of SSA as therapy with positive impact on complication and comorbidities of acromegaly.

Long-term Response to Recombinant Human Growth Hormone Therapy in Indian Children with Growth Hormone Deficiency.

Background:Growth hormone deficiency (GHD) remains the most common indication for use of recombinant human growth hormone (rhGH) therapy in clinical practice. However, there is a paucity of studies focusing on long-term response to rhGH therapy in the Indian context.Aim:To determine the response to rhGH therapy and its predictors in children with GHD followed up at a tertiary care center in North India.Materials and Methods:We performed a retrospective review of the records of children with GHD who received rhGH therapy for at least 1 year. The relevant anthropometric, biochemical and radiological data at baseline and follow-up were recorded.Results:A total of 99 children (64 boys, 35 girls; 61 isolated GHD, 38 multiple pituitary hormone deficiency) were studied. The mean (±SD) age and height SDS at treatment initiation were 12.4 (±3.0) years and −4.0 (±1.1) respectively, while median (IQR) serum insulin-like growth factor 1 (IGF-1) and peak growth hormone level on clonidine stimulation were 73 (25-167) ng/ml and 1.1 (0.4-3.6) ng/ml respectively. The height velocity was highest during the first year of treatment (10.6 ± 3.0 cm/year), declining to 8.7 ± 2.7 and 7.9 ± 2.2 cm/year during second and third year, respectively. Over the subsequent years, there was further graded fall in height velocity, declining to 4.8 ± 3.6 cm/year (n = 2) during the seventh year. The height gain during first year was negatively correlated with age at initiation of treatment, baseline height SDS, baseline serum IGF-1 and peak serum GH level on GH stimulation test, while it showed a positive correlation with bone age delay at baseline. Only baseline height SDS was found to have a significant negative correlation with height gain during the second year.Conclusions:This study provides data on long-term response to rhGH therapy and its predictors in Indian children with GHD.

The Protective Roles of Dietary Selenium Yeast and Tea Polyphenols on Growth Performance and Ammonia Tolerance of Juvenile Wuchang Bream (Megalobrama amblycephala).

In order to investigate protective roles of dietary selenium yeast (SY) and tea polyphenols (TPs) on growth of juvenile Wuchang bream (Megalobrama amblycephala) and its resistance under ammonia stress, juvenile Wuchang bream were randomly assigned into four groups: a control group fed basal diets and three treatment groups fed basal diets supplemented with 0.50 mg/kg SY, 50 mg/kg TPs and a combination of 0.50 mg/kg SY and 50 mg/kg TPs, respectively. After 60 days of feeding, growth parameters of Wuchang bream were measured along with serum hormones and the transcription of growth axis-related genes. Then fish were exposed to ammonia stress of 22.5 mg/L total ammonia nitrogen. Hepatic oxidative damage parameters, antioxidant responses and ultrastructure were evaluated before ammonia exposure (0 h) and at 3, 6, 12, 24, and 48 h after ammonia exposure. Results show that before ammonia exposure, the growth parameters, serum GH and IGF-1 levels as well as the growth axis-related gene expression (gh, ghr2 and igf-1) for the SY and combination groups were higher than those determined for the fish on the control diet. In contrast, the administration of TP alone didn’t have significant effects on the growth parameters and growth-related hormones. After ammonia exposure, compared with the control, remarkable increases in the activity and mRNA expression of hepatic antioxidant enzymes (glutathione peroxidase and catalase superoxide dismutase) in three treatment groups were observed along with decreases of hepatic malondialdehyde and protein carbonylation levels, indicating that the single and combined supplementation of SY and TPs could enhance antioxidant capacity to alleviate oxidative stress and damage by ammonia. Consistent with this finding, alterations of the liver ultrastructure in three treatment groups were less severe and faster recovery than in the control group after ammonia exposure. In conclusion, a basal diet supplemented with the combination of 0.50 mg/kg SY and 50 mg/kg TPs could has very beneficial effects on the whole aspects of the growth and ammonia resistance in Wuchang bream juveniles.

Standardization of Growth Hormone and Insulin-like Growth Factor-I Measurement.

Determination of serum levels of GH and IGF-I is crucial for the diagnosis and treatment of GH deficiency and disorders related to GH excess such as acromegaly and pituitary gigantism. However, significant discrepancies in measured GH values among the methods were observed around the world. In Japan, the Study Committee for GH and Its Related Factors of The Foundation for Growth Science standardized GH values measured with various commercially available GH assay kits by creating formulas to adjust them to their averages. The committee also established reference values for IGF-I in Japanese subjects at all ages from childhood to adulthood. Internationally, collaborators have been working on the harmonization of GH measurements.

Probiotic Bacillus amyloliquefaciens C-1 Improves Growth Performance, Stimulates GH/IGF-1, and Regulates the Gut Microbiota of Growth-Retarded Beef Calves.

Growth retardation of calves is defined as a symptom of impaired growth and development, probably due to growth hormone disorder as well as natural and environmental factors in livestock. The growth-promoting effects of probiotics were determined in 50 growth-retarded growth calves. They were supplied with Bacillus amyloliquefaciens C-1 (Ba, 4 × 1010CFU/d, n = 16), B. subtilis (Bs, 4 × 1010CFU/d, n = 18), and negative control (NC, n = 16) for 30 days. Pre- and post-intervention, the growth performance (weight gain rate, feed intake and feed conversion rate) was analyzed, the serum GH, IGH-1 and immunoglobulin levels were assayed, and the fecal microbiota was detected. Calves in Ba and Bs groups demonstrated increased body weight gain, feed intake and GH/IGF-1 levels, as well as a more efficient feed conversion rate, compared with NC group (P < 0.05). Additionally, the abundances of bacteria contributing to the production of energy and SCFAs (short chain fatty acids), including Proteobacteria, Rhodospirillaceae, Campylobacterales, and Butyricimonas were increased compared with NC group (P < 0.05, FDR < 0.1); and the suspected pathogens, which included Anaeroplasma and Acholeplasma were decreased (P < 0.05, FDR < 0.1) in both the Bs and Ba groups. Akkermansia, which is involved in the intestinal mucosal immune response, was increased in Bs group after intervention (P < 0.05, FDR < 0.1), but exhibited no obvious difference in Ba group. The increased bacterial genera in Ba group were Sphaerochaeta and Treponema (P < 0.05, FDR < 0.1). These results indicate that the probiotics B. amyloliquefaciens and B. subtilis exhibited similar therapeutic potential in terms of growth performance by regulating hormones, and improving the intestinal and rumen development in growth-retarded animals.

Di-(2-ethylhexyl) phthalate induces precocious puberty in adolescent female rats.

Objective(s):Nowadays, Di-(2-ethylhexyl) phthalate (DEHP) is widely used in different kinds of commercial products as a plasticizer. Previous studies have revealed that exposures to DEHP could be associated with precocious puberty in teenagers, but the exact mechanism is yet to be known. Materials and Methods:In this study, 48 prepubertal Wistar female rats were randomly apportioned into 4 groups and orally treated with 0, 250, 500, and 1000 mg/kg/d DEHP from postnatal day 21 up to 4 weeks. Subsequently, we examined the indicators related to the initiation of sexual development. Results:DEHP was able to shorten the vaginal opening time and prolong the estrous cycles of female rats. IGF-1 expression was significantly upregulated by 1000 mg/kg/d DEHP in the hypothalamus, and the hypothalamic, as well as serum levels of GH, were also upregulated by DEHP. It also caused decrements in serum levels of FSH, LH, and T and the increment in level of progesterone. Meanwhile, DEHP was able to exert its effect on the mRNA and protein expression levels of Kiss-1, GPR54, and GnRH in the hypothalamus in pubertal female rats. Conclusion:These findings are revealing that DEHP exposure more likely causes imbalances of hypothalamus functioning in pubertal female rats and thus induces precautious puberty in these animals.

Evaluation of growth hormone response to GHRH plus arginine test in children with idiopathic short stature: role of peak time.

To describe the course of growth hormone response to growth hormone releasing hormone (GHRH) plus arginine provocative test in children with idiopathic short stature (ISS) and to evaluate the role of peak time. A retrospective study was performed analyzing 344 GHRH plus arginine provocative tests performed in children and adolescents with short stature. Serum GH levels were measured at four-time points (T0', T30', T45' and T60') and GH peak was defined as the maximum value at any time point. Mean (T30'-T60') GH value and area under the curve (AUC) were calculated. When analyzing the time of peak at the provocative test, the most frequent peak time was T45' (53.8%) in the ISS group, with no differences in gender, age, and pubertal stage. Analyzing GHD subjects, the most frequent time of peak was T30 (50%). Analyzing the whole population, the GH T0' levels were significantly lower in subjects with the GH peak at T45' than those with the GH peak at T30' (1.7±2.0 vs. 3.2±4.0, p<0.001). In subjects with GH peak at T45', the value of GH peak, AUC and mean GH were significantly higher than in those with GH peak at T30' and T60'. A direct correlation was found between the value of GH peak and growth velocity SDS (r=0.127, p=0.04) and a negative one between GH peak and GH level at T0' (r=-0.111, p=0.04), even when adjusted for gender, age, pubertal stage and BMI Z score. The time peak at 45min seems to be associated with a better response to the test considering GH peak, mean and AUC. Patients with a GH peak at 30min more probably could have a derangement in GH secretion showing worst growth pattern and/or a GH deficiency and should be carefully observed.

Novel genetic cause of idiopathic short stature.

Traditionally, the growth hormone – insulin-like growth factor I (GH – IGF-I) axis is the most important signaling pathway in linear growth, and defects in this axis present as growth hormone deficiencies or IGF-I deficiencies. However, subtle changes in serum levels of GH or IGF-I, caused by gene mutations involved in the GH – IGF-I axis, can present as idiopathic short stature (ISS). This paper briefly discusses GHR and IGFALS. In addition, recent studies have shown that many factors, including paracrine signals, extracellular matrix, and intracellular mechanisms of chondrocytes, regulate the growth plate independent of the GH – IGF-I system. Rapid development of diagnostic technologies has enabled discovery of many genetic causes of ISS. This paper discusses 5 genes, SHOX, NPR2, NPPC, FGFR3, and ACAN, that may lead to better understanding of ISS.

MUSCLE STRENGTH, GH AND IGF-1 IN OLDER WOMEN SUBMITTED TO LAND AND AQUATIC RESISTANCE TRAINING

ABSTRACT Introduction: Aging leads to decline in multiple organ systems associated to hormone alterations and loss of muscle mass and strength. Objective: To evaluate the effects of land and water resistance training on muscle strength, basal serum levels of GH, IGF-1, and IGFBP3 in elderly women. Methods: Subjects were distributed in three groups: land resistance training (LRT; n=10; age: 66.10±2.77 years), water resistance training (WRT; n=10; age: 67.10±3.54 years) and control (CG; n=10; age: 68.80±5.41 years). Muscle strength was assessed with the 1-RM test in bench press (BP) and leg press (LP) exercises. Serum levels of GH, IGF-1, and IGFBP3 were analyzed by chemiluminescence. Results: Repeated measures ANOVA showed elevated muscle strength in the BP only in LRT (D%=60.2%; p=0.0001) when compared to the CG (D%=46.73%, p=0.0001) and WRT (D%=32.49%, p=0.004). LRT and WRT increased muscle strength in LP (D%LRT=57.14%; p=0.004; D%WRT=42.3%; p=0.033). There was an increase in LRT and WRT in the LP when compared to CG (D%=45.59%, p=0.019; D%=43.97%, p=0.026, respectively). IGF-1 was elevated only in LRT (D%=49.72%, p=0.004) from pre- to post-test and when compared to WRT (D%=56.76%, p=0.002) and CG (D%=74.63%, p=0.0001). IGFBP3 levels showed that only WRT increased (D%=26.79%, p=0.044) from pre- to post-test. The IGF-1/IGFBP3 ratio demonstrated that LRT reached intragroup elevation (D%=52.66%, p=0.002) and when compared to WRT (D%=94.11%, p=0.0001) and CG (D%=73.45%, p=0.0001). There was no significant difference in GH. Conclusion: Land resistance training may provide better anabolic effects in elderly women.

Serum leptin levels and GHR-d3/fl gene polymorphism in acromegalic patients with thyroid nodules.

Acromegaly is a rare and serious syndrome that is commonly associated with pituitary neoplasms. Thyroid multinodular disease is a common finding in acromegaly. Leptin is a polypeptide hormone, and studies have shown that it can increase cell proliferation and inhibit apoptosis. The aim of the study was to determine the relationship of serum leptin levels with certain blood parameters and determine if growth hormone receptor (GHR)-d3/fl gene polymorphism is associated with thyroid nodules in acromegalic patients. A total of 24 acromegalic patients with or without thyroid nodules were included in the study. Gene polymorphisms and blood parameters were examined. A marked increase was observed in serum leptin concentration in acromegalic patients with thyroid nodules compared to patients without them (p < 0.05). GH levels were lower in patients without nodules than in patients with nodules (p < 0.05). Blood glucose levels were higher in patients with nodules compared to those without them (p < 0.05), and the presence of thyroid nodules was associated with decreased blood low-density lipoprotein (LDL) levels compared to patients without nodules (p < 0.05). A significant relationship was observed between growth hormone receptor (GHR)-d3/fl gene polymorphism and leptin levels in acromegalic patients with thyroid nodules (p < 0.001). These data from acromegalic patients indicate that thyroid nodules are associated with increased serum leptin, GH and blood glucose levels and with decreased LDL levels. GHR-d3/fl gene polymorphism status was strongly related to higher leptin levels.

Hypothalamic growth hormone receptor (GHR) controls hepatic glucose production in nutrient-sensing leptin receptor (LepRb) expressing neurons

ObjectiveThe GH/IGF-1 axis has important roles in growth and metabolism. GH and GH receptor (GHR) are active in the central nervous system (CNS) and are crucial in regulating several aspects of metabolism. In the hypothalamus, there is a high abundance of GH-responsive cells, but the role of GH signaling in hypothalamic neurons is unknown. Previous work has demonstrated that the Ghr gene is highly expressed in LepRb neurons. Given that leptin is a key regulator of energy balance by acting on leptin receptor (LepRb)-expressing neurons, we tested the hypothesis that LepRb neurons represent an important site for GHR signaling to control body homeostasis. MethodsTo determine the importance of GHR signaling in LepRb neurons, we utilized Cre/loxP technology to ablate GHR expression in LepRb neurons (LeprEYFPΔGHR). The mice were generated by crossing the Leprcre on the cre-inducible ROSA26-EYFP mice to GHRL/L mice. Parameters of body composition and glucose homeostasis were evaluated. ResultsOur results demonstrate that the sites with GHR and LepRb co-expression include ARH, DMH, and LHA neurons. Leptin action was not altered in LeprEYFPΔGHR mice; however, GH-induced pStat5-IR in LepRb neurons was significantly reduced in these mice. Serum IGF-1 and GH levels were unaltered, and we found no evidence that GHR signaling regulates food intake and body weight in LepRb neurons. In contrast, diminished GHR signaling in LepRb neurons impaired hepatic insulin sensitivity and peripheral lipid metabolism. This was paralleled with a failure to suppress expression of the gluconeogenic genes and impaired hepatic insulin signaling in LeprEYFPΔGHR mice. ConclusionThese findings suggest the existence of GHR-leptin neurocircuitry that plays an important role in the GHR-mediated regulation of glucose metabolism irrespective of feeding.

Levels of glucose-regulatory hormones in patients with non-islet cell tumor hypoglycemia: including a review of the literature.

Non-islet cell tumor hypoglycemia (NICTH) is one of the causes of spontaneous hypoglycemia. The pathogenesis of NICTH is thought to be an excessive production by tumors of big insulin-like growth factor (IGF)-II. This study investigated the levels of glucose-regulatory hormones in patients with NICTH with high serum levels of big IGF-II (big IGF-II group) and compared these with profiles of patients with spontaneous hypoglycemia with normal IGF-II (normal IGF-II group). Circulating IRI, CPR, ACTH, cortisol, GH, and IGF-I levels measured during hypoglycemic episodes were examined retrospectively in 37 patients with big IGF-II producing NICTH and 6 hypoglycemic patients with normal IGF-II. The hormone profile data of 15 patients with NICTH from published case reports were reviewed and included in the analyses. Mean plasma glucose levels (36 vs. 29 mg/dL), serum IRI (0.53 vs. 0.37 μIU/mL), CPR (0.15 vs. 0.20 ng/mL), IGF-I SDS (-3.55 vs. -3.18 SD) and ACTH levels (27.3 vs. 33.8 pg/mL) were not significantly different between the big and normal IGF-II groups. However, mean serum GH (0.85 vs. 9.62 ng/mL) and plasma cortisol levels (16.2 vs. 34.5 μg/dL) were significantly lower in the big IGF-II group than in the normal IGF-II group (both p<0.05). In conclusion, although the magnitude of the decrease in insulin and IGF-I levels did not differ between spontaneous hypoglycemic patients caused by other etiologies, patients with NICTH tended to have low basal GH levels during hypoglycemic episodes. These differences in hormone profile may be helpful for selecting patients who require analysis of IGF-II.

Dynamic response of C-type natriuretic peptide and its aminoterminal propeptide (NTproCNP) to growth hormone treatment in children with short stature.

C-type natriuretic peptide (CNP) and its aminoterminal propeptide (NTproCNP) are potential biomarkers of recombinant human growth hormone (rhGH) efficacy. The objective of this study was to describe the pharmacodynamics of plasma CNP and NTproCNP levels in response to rhGH treatment and to identify the optimal time of sampling after starting rhGH. This was a prospective, observational study. Subjects were treated with rhGH for 1 year, with blood sampled at regular intervals. Eighteen prepubertal children, eight with low levels of GH on biochemical testing and ten with idiopathic short stature, completed the study. Blood levels of CNP, NTproCNP, GH, insulin-like growth factor-I, leptin and bone-specific alkaline phosphatase were measured. Anthropometrics were obtained. Plasma levels of both CNP and NTproCNP reached peak levels 7-28 days after starting rhGH treatment and then declined to intermediate levels through the first year. Plasma NTproCNP levels after 14 days trended towards a correlation with height velocity after 6 and 12 months of treatment. Unexpectedly, serum GH levels measured 2 and 28 days after starting rhGH correlated strongly with height velocity after 6 and 12 months of treatment. This study identified 14 days after starting rhGH treatment as the optimal time for assessing CNP and NTproCNP levels as biomarkers of rhGH efficacy. Additionally, we identified GH levels as a potential biomarker. Larger, prospective studies are now needed to test the clinical utility of these biomarkers.

Effects of prolonged alcohol exposure on somatotrophs and corticotrophs in adult rats: Stereological and hormonal study

Exposure to alcohol alters many physiological processes, including endocrine status. The present study examined whether prolonged alcohol (A) exposure could modulate selected stereological and hormonal aspects of pituitary somatotrophs (growth hormone-GH cells) and corticotrophs (adrenocorticotropic hormone-ACTH cells) in adult rats. Changes in pituitary gland volume; the volume density, total number and volume of GH and ACTH cells following alcohol exposure were evaluated using a stereological system (newCAST), while peripheral GH and ACTH levels were determined biochemically.Our results demonstrated the reduction (p<0.05) of the volume density (37%) and volume of GH cells (29%) in the group A. Also, there was a tendency for the total number of GH cells to be smaller in the group A. Serum GH level was significantly decreased (p<0.05; 70%) in the group A when compared to control values. Moreover, prolonged alcohol exposure induced declines (p<0.05) in volume density (24%) and volume of ACTH cells (29%). The total number of ACTH cells and ACTH level were higher (p<0.05; 42%) in the group A than in control rats.Collectively, these results indicate that prolonged alcohol exposure leads not only to changes in GH and ACTH hormone levels, but also to alterations of the morphological aspects of GH and ACTH cells within the pituitary.

Effects of GHRP-2 and Cysteamine Administration on Growth Performance, Somatotropic Axis Hormone and Muscle Protein Deposition in Yaks (Bos grunniens) with Growth Retardation.

The objective of this study was to investigate the effects of growth hormone-releasing peptide-2 (GHRP-2) and cysteamine (CS) administration on growth performance in yaks with growth retardation and try to elucidate its regulatory mechanisms. Trial 1, thirty-six 1-year-old Qinghai high plateau yaks (body weight 38–83.2 kg) were randomly chosen for body weight and jugular blood samples collection. The relationship between body weight and serum GHRH (P < 0.05, R = 0.45), GH (P < 0.05, R = 0.47), IGF-1 (P < 0.05, R = 0.62) was significantly correlated in yaks colonies with lighter body weights. Trial 2, fifteen 1-year-old Qinghai high plateau yaks with growth retardation (average body weight 54.8 ± 8.24 kg) were randomly selected and assigned to negative control group (NG), GHRP-2 injection group (GG) and cysteamine feeding group (CG), with 5 yaks per group. Another five 1-year-old Qinghai high plateau yaks with normal growth performance (average body weight 75.3 ± 2.43 kg) were selected as positive control group (PG). The average daily gain (ADG) of the GG and CG were significantly higher than those in the PG and NG (P < 0.05). Both GHRP-2 and CS administration significantly enhanced the myofiber diameter and area of skeletal muscle (P<0.05). GHRP-2 significantly enhanced the serum GH and IGF-1 levels (P < 0.05), and up-regulated GHR, IGF-1 and IGF-1R mRNA expression in the liver and skeletal muscle (P < 0.05), enhanced the mRNA expression of PI3K, AKt and mTOR in the skeletal muscle (P<0.05). CS significantly reduced the serum SS levels and the hypothalamus SS mRNA expression (P < 0.05), and enhanced GHR and IGF-1 mRNA expression in the liver (P < 0.05), decreased the mRNA expression of muscle atrophy F-box (Atrogin-1) and muscle ring finger 1 (MuRF1) mRNA (P < 0.05). Conclusions: Growth retardation in yaks was primarily due to somatotropic axis hormones secretion deficiency. Both GHRP-2 and CS administration can accelerate growth performance and GH, IGF-1 secretion in yaks with growth retardation. GHRP-2 enhanced muscle protein deposition mainly by up-regulated the protein synthesis pathways, whereas CS worked mainly by down-regulated the ubiquitin-proteasome pathway.

Glucose Tolerance is Improved Following Surgery for Silent Somatotroph Adenoma

Although the excessive secretion of GH leads to insulin resistance enhancement, the involvement of a silent somatotroph adenoma in abnormal glucose tolerance has not been elucidated. A 50 - yearold man was admitted with a headache and bitemporal hemianopia caused by a pituitary macroadenoma. He had no physical signs and symptoms of acromegaly nor hypopituitarism, and his baseline serum levels of GH and insulin - like growth factor-1 (IGF-1) were normal. However, a 75 - g oral glucose tolerance test (OGTT) showed unsuppressed GH concentrations as well as plasma glucose levels consistent with diabetes pattern. A transsphenoidal adenomectomy was performed, and we diagnosed the patient as having a silent somatotroph adenoma based on positive GH in the immunohistochemistry. Postoperative OGTT showed GH suppression and a normal pattern of plasma glucose levels after glucose loading. The post-surgery homeostasis model assessment insulin resistance index (HOMA - IR) and the Matsuda Index indicated improved insulin sensitivity in the absence of perioperative body-mass-index change. These observations suggest that reversible abnormal glucose tolerance is associated with a silent somatotroph adenoma in this patient.

Case-control study of expansion of heart cavity and great vessel diameters in acromegaly

To investigate alternations of heart cavity and great vessel diameters and their risk factors in acromegalic patients. Ninety-two cases, diagnosed as acromegaly, were selected as research subjects from January 2013 to December 2013 in Peking Union Medical College Hospital. There were 37 males and 55 females with an average age of 41.2 years (SD, 12.5 years, range from 19 to 67 years old). Ninety-two sex and age matched healthy individuals were selected as controls. Disease history, echocardiography, endocrine hormone levels were collected to make contractive analysis. We analyzed the related risk factors of great vessel diameters expansion with binary logistic regression analysis and finally obtained the OR (odd ratio) and predictive formula. Left ventricle end-diastolic diameter (LVEDD), left ventricle end-systolic diameter (LVESD), left atrium longitudinal dimension (LALD), right ventricle longitudinal dimension (RVLD), aortic root dimension (AORD), ascending aorta (AA), main pulmonary artery (MPA) were higher in patients with acromegaly than in healthy people, P<0.05. The comparison between expanded vessel diameters and normal vessel diameters in acromegalics showed that difference of disease duration was of statistical significance, OR= 1.011. We got the formula: logit (ADE)=-3.420+0.011 × duration of disease. Heart cavity and vessel diameters in acromegalic patients were higher than that in public. Expanding of great vessel diameters mainly depend on duration of disease instead of serum GH and IGF-1 level, and the duration of disease is the risk factor of the expansion of great vessel diameters.