Growth Hormone Receptor Gene Expression Research Articles

Effects of feeding diets with zinc-l-selenomethionine on growth performance of broilers subjected to cyclic heat stress.

Limited information exists on the use of zinc-l-selenomethionine (Zn-L-SeMet) in broiler diets and its effects on the growth performance, body temperature, mortality rates, blood profile, and gene expression, especially when animals are reared under cyclic heat stress conditions. This study aimed to investigate the impact of Zn-L-SeMet in broiler diets from 1 to 42days of age reared under cyclic heat stress and its effects on growth performance, cloacal temperatures, mortality rate, blood parameters, and insulin-like growth factor 1 (IGF-1) and growth hormone receptor (GHR) gene expression in the breast muscle. A total of 1000 male Cobb 500® broiler chicks were randomly assigned to five treatments: 0, 0.15, 0.23, 0.47, and 1.30mg/kg of Zn-L-SeMet. Each treatment consisted of 10 replicates with 20 birds each. No statistically significant differences in growth performance were observed from 1 to 21days of age (P > 0.05). However, from 1 to 42days, feed intake (FI) and feed conversion ratio (FCR) decreased linearly (P < 0.05). Cloacal temperatures showed no significant effects (P > 0.05), while overall mortality rate exhibited a quadratic response (P < 0.05), with the optimal inclusion level predicted to reduce broiler mortality at 0.71mg/kg. Triglyceride (TRG) levels increased with 0.97mg/kg (P < 0.05), and gama-glutamil transferase (GGT) levels decreased with the inclusion of 1.19mg/kg (P < 0.05). No significant effects on IGF-1 and GHR gene expression were found (P > 0.05). In conclusion, the inclusion of 1.30mg/kg of Zn-L-SeMet in diets of heat-stressed broilers improved growth performance from 1 to 42days of age. An inclusion of 0.71mg/kg reduced mortality rate, while 0.97mg and 1.19mg increased and reduced TRG and GGT levels, respectively.

Metabolic memory determines gene expression in liver and adipose tissue of undernourished ewes

The aim of this work was to determine the effects of undernutrition on gene expression in liver and adipose tissue, and on the hepatic concentration of insulin like growth factor 1 (IGF1) and insulin, in pregnant ewes with different initial body condition score (iBCS). Thirty-six Rasa Aragonesa ewes were divided into 2 groups with different BCS: BCS > 2.75 (n = 19; high, H) and BCS < 2.25 (n = 17; low, L), and were randomly assigned to two nutritional treatments: 1.5 (control, C) or 0.5 (undernourished, U) times the daily maintenance requirements. Thus, the final four groups were: high-iBCS control (HC, n = 9), high-iBCS undernourished (HU, n = 10), low-iBCS control (LC, n = 9) and low-iBCS undernourished (LU, n = 8). High-iBCS ewes presented greater liver IGF1 mRNA expression (P < 0.05), which is consistent with higher liver IGF1 and insulin concentrations (P = 0.10 and P < 0.05, respectively), and with greater liver growth hormone receptor (GHR) gene expression (P < 0.05). These data, and the trend for more leptin receptor type b (LEPR-b) mRNA in high-iBCS ewes (P = 0.09) suggest a better anabolic status. Furthermore, undernourished ewes presented lower hepatic insulin like growth factor binding protein 3 (IGFBP3) gene expression (P = 0.05), suggesting a shift in the availability of IGFs in plasma and therefore, in their action in target tissues. In the adipose tissue, U ewes presented lower GHR mRNA expression than C animals (P < 0.05), being greatest in the high-iBCS control group. As expected, leptin (LEP) gene expression in adipose tissue was greater in high-iBCS than in low-iBCS ewes (P < 0.05). Nevertheless, the most interesting finding was the organ-specific pattern of LEPR-b gene expression: in contrast to the liver, the greatest adipose tissue LEPR-b gene expression was observed in the low-iBCS undernourished ewes (P < 0.05). In summary, the present study demonstrates that the initial body condition score evokes different, even contrasting, responses in key metabolic organs (i.e., liver and adipose tissue) of control and undernourished ewes.

Expression of PTX3, GHR and GDF9 genes in cumulus cells and oocytes in relation to developmental competence of Bos indicus

The present study was conducted to evaluate the level of expression (mRNA) of specific developmental marker genes, viz. Growth Differentiation Factor 9 (GDF9), Growth Hormone Receptor (GHR) and Pentraxin 3 (PTX3) in bovine cumulus cells and oocytes in relation to in vitro developmental competence. Good quality Cumulus- Oocytes- Complexes (COCs) were selected for in vitro maturation and fertilization. The mean percentage of in vitro fertilization performance was 59.84 ± 4.28. The relative quantification values of GDF9 were 2.38, 98.13, 1 and 132.58; GHR were 4.31, 1.47, 1 and 43.58; PTX3 were 0.28, 0, 1 and 0.5 in immature cumulus cells, immature oocyte, mature cumulus cells and mature oocyte respectively when compared to the reference control. The expression of GDF9 gene was found to be up-regulated in oocytes compared to cumulus cells. The expression pattern of GDF9 was relatively more in in vitro matured oocytes compared to cumulus groups. The expression of GHR gene was up-regulated in oocytes. The relative abundance of PTX3 was slightly up-regulated in mature cumulus cells as compared to immature counterparts. Thus, GDF9 and GHR genes could be considered as embryonic developmental markers for bovine oocytes, while PTX3 gene for bovine cumulus cells.

Gene expression analysis on growth, development and toxicity pathways of male Nile tilapia (Oreochromis niloticus), after acute and sub-chronic benzo (α) pyrene exposures

Benzo[α]pyrene (BaP), a lipophilic polycyclic aromatic hydrocarbon (PAH), is a contaminant widely distributed in aquatic systems. Its presence in freshwater organisms is of great concern; particularly in Nile tilapia (Oreochromis niloticus), due to its economic relevance. The aim of this study is to evaluate the effects of acute and sub-chronic BaP exposures on molecular growth/development responses, toxicity to DNA pathways and xenobiotic metabolism. Negative morphometric changes (the growth condition factor, hepatosomatic and gonadosomatic indices), the fluorescent aromatic compounds (FACs) in bile were also studied in order to understand the mechanisms of action of BaP. Genes involved in the growth hormone GH/insulin-like growth factor 1 (IGF-1) were measured, such as IGF1–2 with the growth hormone receptor gene expression GHR1–2, and the endocrine disruption biomarker vitellogenin (VTG). Acute exposure elicited changes in the GH/IGF axis, mainly in the GHR1 and in IGF1 mRNA levels without affecting the GHR2 expression. While sub-chronic exposure had less effect on both GHR and IGF genes. The most notable tissue-specific effects and morphometric endpoints were observed upon sub-chronic exposure, such as changes in key genes involved in detoxification, DNA damage, and altered reproductive morphological endpoints; showing that sub-chronic BaP doses have longer-lasting toxic effects. This study shows that sub-chronic BaP exposure may compromise the health of Nile tilapia and sheds light on the changes of the GH/IGF axis and the biotransformation of the xenobiotics due to the presence of this contaminant.

Expression of IGF-1, IGF-1 Receptor and Growth Hormone Receptor in Hepatic Tissue in Adults Across the Spectrum of Nonalcoholic Fatty Liver Disease (NAFLD)

Background: Obesity is a state of relative growth hormone (GH) and insulin-like growth factor-1 (IGF-1) deficiency, and the GH/IGF-1 axis has been implicated in the pathophysiology of nonalcoholic fatty liver disease (NAFLD) and the progression to steatohepatitis (NASH) in preclinical models and human studies. GH has both lipolytic and anti-inflammatory properties while IGF-1 has been implicated in reducing hepatic fibrosis and promoting hepatic regeneration. The GH/IGF-1 axis may be a therapeutic target in NAFLD/NASH, however, IGF-1, IGF-1 receptor (IGF-1R) and GH receptor (GHR) expression in adult human hepatic tissue has not been studied across the spectrum of disease severity. Methods: We quantified IGF-1, IGF-1R, and GHR gene expression in hepatic tissue from 318 adults with obesity using the Nanostring nCounter assay. Subjects were classified into four categories of disease severity based on histopathology: normal liver histology (NLH) (n=76, 24%), steatosis only (Steatosis) (n=88, 28%), NASH without fibrosis (NASH F0) (n=72, 23%), and NASH with fibrosis (NASH F1-F4) (n=82, 26%). Gene expression analysis is presented as normalized gene counts by group with p-value of the generalized linear model controlled for age, sex and BMI. Results: Mean (±SD) age (whole cohort 44.0±12 years) and BMI (whole cohort 46.8±7.2 kg/m2) did not differ across groups (p=0.2 for both). ALT was higher with increasing disease severity (NLH 30.1±26.7, Steatosis 31.9±15.7, NASH F0 35.7±16.5, NASH F1-4 48.4±34.9, p<0.001). IGF-1 gene expression was lower in all NAFLD/NASH groups compared to the NLH reference group (NLH 485.4±292.7; Steatosis 396.3±238.0, p=0.04; NASH F0 349.8±220.1, p=0.01 and NASH F1-4 341.2±268.6, p=0.03, all p-values vs NLH). There was no difference in IGF-1R or GHR gene expression across disease severity groups (IGF-1R NLH 43.3±10.2, Steatosis 41.4±11.6, NASH F0 38.8±8.8 and NASH F1-4 39.1±8.1, p>0.05 between any disease state; GHR NLH 6382±2366, Steatosis 6544±2699, NASH F0 7220±2542 and NASH F1-4 5997±2352, p>0.05 between any disease state). Conclusion: We demonstrated that IGF-1 gene expression was lower in liver tissue from patients with NAFLD and NASH than healthy controls. This is consistent with our prior finding that histologic NASH and fibrosis are associated with lower serum IGF-1 levels. Moreover, we demonstrated that hepatic IGF-1R and GHR gene expression is not lower in liver tissue from patients with NAFLD and does not decline across disease severity. This reinforces our prior finding that GHR staining intensity and zonality by immunohistochemistry does not change with increasing disease severity in NAFLD/NASH. These data demonstrate that the GH axis is relatively suppressed but that expression of GHR and IGF-1R receptors is stable with worsening disease severity in NAFLD/NASH, suggesting that GH augmentation may be a viable therapeutic target in NAFLD.

Identification of the cDNA Encoding the Growth Hormone Receptor (GHR) and the Regulation of GHR and IGF-I Gene Expression by Nutritional Status in Reeves' Turtle (Chinemys reevesii).

Chinemys reevesii (Reeves’ turtle) is a slow-growing reptile that is distributed widely across China. Prior to this study, the cDNA sequence of the growth hormone receptor (GHR) in the Reeve’s turtle, or how periods of starvation might influence the gene expression of GHR and insulin-like growth factor I (IGF-I) in this species, were unknown. Here, we identified the full-length sequence of the cDNA encoding GHR in Reeves’ turtle by using RT-PCR and RACE. The full-length GHR cDNA was identified to be 3936 base-pairs in length, with a 1848 base-pair open reading frame (ORF) that encodes a 615 amino acid protein. Analysis showed that GHR mRNA was detectable in a wide range of tissues; the highest and lowest levels of expression were detected in the liver and the gonad, respectively. IGF-I was also expressed in a range of tissues, but not in the gonad; the highest levels of IGF-I expression were detected in the liver. After 4 weeks of fasting, the expression levels of GHR and IGF-I in the liver had decreased significantly; however, these gradually returned to normal after refeeding. We report the first cloned cDNA sequence for the GHR gene in the Reeve’s turtle. Our findings provide a foundation from which to investigate the specific function of the GHR in Reeve’s turtle, and serve as a reference for studying the effects of different nutrient levels on GHR expression in this species.

GH-IGF-1 Axis in Children with Cystic Fibrosis.

To verify whether growth hormone receptor (GHR) gene expression plays a role in growth of children with cystic fibrosis (CF), as a consequence of the chronic inflammatory condition and malnutrition. We enrolled 49 prepubertal patients (24 males and 25 females) affected by CF in a stable clinical condition, 19 of whom had been diagnosed through newborn screening and 30 following presentation of symptoms. Patients had no significant comorbidity affecting growth or cystic fibrosis transmembrane conductance regulator (CFTR)-related diabetes requiring insulin therapy. Blood was collected during two follow-up visits to measure insulin-like growth factor (IGF-I), growth hormone-binding protein (GHBP), and GHR gene expression. Recruited as a control group were 52 healthy children, sex- and age-matched, were recruited as a control group. We compared body mass index (BMI), height, weight, IGF-I, GHBP, and GHR gene expression values (evaluated by Chemiluminescent Immunometric assay; ELISA and real-time PCR, respectively) in CF patients diagnosed through newborn screening (NBS) or by symptoms (late diagnosis [LD]) and in healthy controls. BMI increased significantly in patients between the time of diagnosis and check-up (P<0.001), particularly in the LD group; median value was lower at diagnosis and significantly higher (P<0.001) at follow-up visits compared to controls. At initial evaluation, higher levels of IGF-I (not statistically significant) were found in both the NBS group and the LD group compared to the control group. At the second evaluation, significantly higher levels of IGF-I (P=0.003) were found in both the NBS and LD groups compared to controls; GHR mRNA expression had significantly increased (P=0.013) in LD patients compared with the first evaluation and was significantly higher in the NBS and LD groups than in controls. GHBP values had significantly increased (P=0.047) in the NBS group after one year of therapy compared to first visit levels and were significantly higher (P<0,0001) in the NBS and LD groups compared to controls. In our LD patients during childhood, we observed good auxological values and a GH/IGF-I axis function within normal range for the factor evaluated. However, earlier diagnosis through NBS might further minimize and prevent growth retardation, by reducing the duration of symptoms before treatment.

Sex-specific effects of a microsatellite polymorphism on human growth hormone receptor gene expression

Growth hormone (GH) binds to its specific receptor (GHR) at the surface of target cells activating multiple signaling pathways implicated in growth and metabolism. Dysregulation of GHRs leads to pathophysiological states that most commonly affect stature. We previously showed the association of a polymorphic (n = 15–37) GT microsatellite in the human GHR gene promoter with short stature in a sex-specific manner. In the present study we evaluated the functional relevance of this polymorphism in regulating GHR expression. Using luciferase reporter assays, we found that the GT repeat had a significant cis regulatory effect in response to HIF1α and a potential repressor role following C/EBPβ stimulation. Using a digital PCR application to measure allelic imbalance (AI), we showed a high prevalence of AI (∼76%) at the GHR locus in lymphoblastoid cell lines (LCLs), with a significantly higher degree of imbalance in LCLs derived from males. Examination of expression of GHR as well as other members of the GH-IGF1 axis in the LCLs revealed significant associations of GHR, IGF1 and BCL2 expression with GT genotype in a sex-specific manner. Our results suggest that this GT microsatellite exerts both cis and trans effects in a sex-specific context, revealing a new mechanism by which GHR gene expression is regulated.

Efficacy of cerebrolysin on dentate gyrus of hippocampus after experimentally induced acute ischemic stroke in adult albino rats (Histological, immunohistochemical and biochemical study)

Background: Acute ischemic stroke (AIS) is a brain medical disorder characterized by the sudden loss of blood circulation to an area of the brain, resulting in a loss of its neurologic function. Cerebrolysin is a mixture of neuropeptides and free amino acids. Aim of the work: This study aimed to evaluate the role of cerebrolysin in ameliorating the histological, immunohistochemical and biochemical harm in post ischemic stroke and also to assess its dose dependent effect.Materials and Methods: Thirty adult male rats were divided into 3 equal groups; control, ischemic and post ischemic treated groups. After dissecting hippocampal dentate gyrus prepared sections were stained with hematoxylin and eosin, Erβ and calretinin proteins. Oxidative stress parameters, TNF α, and HSP-70 assay. Also, Gh receptor gene expression and DNA fragmentation test were measured. Immunoperoxidase reactions for GFAPin astrocyte was estimated. Statistical analysis was conducted. Results: Ischemia group showed decrease number of granule cells with small dark stained nuclei, areas of cell loss and numerous spindle shaped cells in the sub-granular zone. A faint positive immunoreaction for ERβ in nuclei of granular cells and negative reaction for calretinin was detected in granule cells. Antioxidant enzymes in the brain tissue as MDA,TNF α and HSP-70 were significantly elevated in ischemic group compared to control and post ischemic treated groups. Gh receptor gene were decreased, while Fragmentation index of DNA was significantly increased. Administration of 2.5 mg/kg cerebrolysinshowed partial improvement, whereas, 5 mg/kg dose displayed more ameliorative effects. Increased GFAP immune-expression in the cytoplasm of astrocytes in ischemic group compared to control and post ischemic treated groups. Conclusion: Cerebrolysin was effective in experimentally induced AIS (Acute ischemic stroke) in a dose-dependent manner as proved by improving the histological structure, immunohistochemical reactions and biochemical parameters of the dentate gyrus of hippocampus in adult male albino rats.

Growth Hormone Receptor Gene Expression Increase Reflects Nutritional Status Improvement in Patients Affected by Crohn's Disease.

Background: We proposed to verify the role of growth hormone receptor gene expression in growth failure of children with Crohn's disease (CD).Methods: We measured serum levels of growth hormone binding protein (GHBP) and insulin-like growth factor-I (IGF-I), and growth hormone receptor (GHR) gene expression in peripheral blood mononuclear cells of 21 patients with CD (before and after therapy) and in 27 age-sex-matched controls.Results: At diagnosis, significantly lower insulin-like growth factor-I and growth hormone binding protein levels were found in the CD group compared to the controls. Growth hormone receptor mRNA expression was lower in patients at diagnosis compared to the controls, even though the difference did not reach statistical significance, and significantly increased in patients in the following year. Insulin-like growth factor-I levels showed significant improvements 1 year after diagnosis compared to basal levels. On the contrary, growth hormone binding protein values had not significantly changed after 1 year of therapy.Conclusion: Our study raises the hypothesis of another mechanism through which cytokines interact with the growth hormone/insulin-like growth factor-I (GH/IGF-I) axis.

Effects of starter feeding and early weaning on GHR mRNA expression in liver and rumen of lambs from birth to 84 days of age

ABSTRACTThe growth hormone receptor (GHR) is associated with animal growth and development. To investigate such effects on GHR gene expression, a total of 102 Hu lambs were randomly allocated to one of three groups (Group 1: starter diet from 7 d of age, weaning at 56 d of age; Group 2: starter diet from 42 d of age, weaning at 56 d of age; Group 3: starter diet from 7 d of age; weaning at 28 d of age). Six lambs from each group were sacrificed every 14 d to investigate the effects of starter feeding and weaning age on GHR mRNA expression in the liver and rumen. The results revealed that GHR mRNA expression was significantly higher in the liver and rumen (p < 0.05) than in other tissues. Early starter feeding up-regulated hepatic GHR mRNA expression on days 14, 28, 42 and 56 and ruminal GHR mRNA expression on days 28, 42, 70, and 84 (p < 0.05). Early weaning up-regulated hepatic GHR mRNA expression on days 56, 70 and 84 and ruminal GHR mRNA expression on days 42, 56, 70 and 84 (p < 0.05). Dietary and weaning regimes and age affected the hepatic and ruminal GHR mRNA expression.

Leptin stimulates hepatic growth hormone receptor and insulin-like growth factor gene expression in a teleost fish, the hybrid striped bass

Leptin is an anorexigenic peptide hormone that circulates as an indicator of adiposity in mammals, and functions to maintain energy homeostasis by balancing feeding and energy expenditure. In fish, leptin tends to be predominantly expressed in the liver, another important energy storing tissue, rather than in fat depots as it is in mammals. The liver also produces the majority of circulating insulin-like growth factors (IGFs), which comprise the mitogenic component of the growth hormone (GH)-IGF endocrine growth axis. Based on similar regulatory patterns of leptin and IGFs that we have documented in previous studies on hybrid striped bass (HSB: Morone saxatilis×Morone chrysops), and considering the co-localization of these peptides in the liver, we hypothesized that leptin might regulate the endocrine growth axis in a manner that helps coordinate somatic growth with energy availability. Using a HSB hepatocyte culture system to simulate autocrine or paracrine exposure that might occur within the liver, this study examines the potential for leptin to modulate metabolism and growth through regulation of IGF gene expression directly, or indirectly through the regulation of GH receptors (GHR), which mediate GH-induced IGF expression. First, we verified that GH (50nM) has a classical stimulatory effect on IGF-1 and additionally show it stimulates IGF-2 transcription in hepatocytes. Leptin (5 and/or 50nM) directly stimulated in vitro GHR2 gene expression within 8h of exposure, and both GHR1 and GHR2 as well as IGF-1 and IGF-2 gene expression after 24h. Cells were then co-incubated with submaximal concentrations of leptin and GH (25nM each) to test if they had a synergistic effect on IGF gene expression, possibly through increased GH sensitivity following GHR upregulation by leptin. In combination, however, the treatments only had an additive effect on stimulating IGF-1 mRNA despite their capacity to increase GHR mRNA abundance. This suggests that leptin’s stimulatory effect on GHRs may be limited to enhancing transcription or mRNA stability rather than inducing full translation of functional receptors, at least within a 24-h time frame. Finally, leptin was injected IP (100ng/g and 1μg/gBW) to test the in vivo regulation of hepatic IGF-1 and GHR1 gene expression. The 100ng/g BW leptin dose significantly upregulated in vivo IGF-1 mRNA levels relative to controls after 24h of fasting, but neither dosage was effective at regulating GHR1 gene expression. These studies suggest that stimulation of growth axis component transcripts by leptin may be an important mechanism for coordinating somatic growth with nutritional state in these and perhaps other fish or vertebrates, and represent the first evidence of leptin regulating GHRs in vertebrates.

Endocrine control of canine mammary neoplasms: serum reproductive hormone levels and tissue expression of steroid hormone, prolactin and growth hormone receptors.

BackgroundNeoplasms of the mammary gland are among the most common diseases in female domestic dogs (Canis familiaris). It is assumed that reproductive hormones influence tumorigenesis in this species, although the precise role of the endocrine milieu and reproductive state is subject to continuing discussion. In line with this, a recent systematic review of available data on the development of mammary neoplasms revealed weak evidence for risk reduction after neutering and an effect of age at neutering. Investigation of several hormone receptors has revealed decreased expression of estrogen receptor-alpha (ERα, ESR1), progesterone (P4) receptor (PGR), prolactin (PRL) receptor (PRLR) and growth hormone receptor (GHR) associated with neoplastic differentiation of mammary tissues. In other studies, increased levels of estrogens, progesterone and prolactin were found in serum and/or tissue homogenates of dogs with malignant neoplasms. However, the association between these entities within one animal population was never previously examined. Therefore, this study investigated the association between circulating serum concentrations of estradiol-17β, progesterone and prolactin, and gene expression of ERα (ESR1), ERβ (ESR2), PGR, PRLR, PRL and GHR, with respect to reproductive state (spayed vs. intact) and cycle stage (anestrus vs. diestrus). Additionally, the expression of E-cadherin (CDH-1) was evaluated as a possible indicator of metastatic potential.ResultsFor all receptors, the lowest gene expression was found in malignant tumors compared to normal tissues of affected dogs. Steroid levels were not influenced by their corresponding receptor expression in mammary neoplasms, but increased PRL levels were negatively associated with low PRLR gene expression in malignant tumors. The expression of CDH-1 was influenced by tumor malignancy and cycle stage, i.e., the highest gene expression was found in benign mammary tumors in diestrous dogs compared to normal and malignant mammary tissues of anestrous and spayed dogs.ConclusionsHerein, it has been confirmed that transformation towards malignant neoplasms is associated with significant reduction of gene expression of particular hormone receptors. Only PRLR in malignant tumors seems to be influenced by circulating PRL levels. In dogs, CDH-1 can be used as a prognostic factor; its expression, however, in benign tumors is influenced by cycle stage.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0546-y) contains supplementary material, which is available to authorized users.

Effects of methionine supplementation on the expression of protein deposition-related genes in acute heat stress-exposed broilers.

The objective of this study was to evaluate the effect of heat stress and methionine supplementation on the gene expression of insulin-like growth factor I (IGF-I), growth hormone receptor (GHR), phosphatidylinositol 3-kinase, and regulatory 1 (PI3KR1) in the liver, as well as the expression of the atrogin 1 and cathepsin L2 (CTSL2) genes in the breast muscle of broilers. Broilers from 1–21 and 22–42 days of age were divided into three treatments related to methionine supplementation as follows: without methionine supplementation (MD), recommended level of methionine (DL1), and excess supplementation of methionine (DL2). The animals were either maintained at a thermal comfort temperature or exposed to heat stress (HS) (38°C for 24 hours, starting on day 20 or day 41 for experiments 1 and 2, respectively). The heat stress increased the body temperature at both ages. Starter period: The HS animals presented increased plasma creatinine content (P<0.0001) and the highest CTSL2 gene expression (P<0.0001). The methionine supplementation increased the IGF-I (P = 0.0144) and GHR (P = 0.0011) gene expression and decreased the CTSL2 (P = 0.0004) and atrogin 1 (P = 0.0012) gene expression. Grower period: Significant effects for the interaction between supplementation and environment were observed for GHR (P = 0.0252) and CTSL2 (P = 0.0011) gene expression. The highest GHR expression was observed in animals that remained in thermal comfort on the DL2 diet, and the lowest expression occurred in the HS animals fed the MD diet. For CTSL2, the HS animals fed the MD diet presented the highest CTSL2 gene expression, and the lowest expression was observed in the animals maintained at thermal comfort on DL1 and DL2 diets. Only methionine supplementation had effect on atrogin-1 gene expression (P<0.0001), with higher methionine content in the diet lower atrogin-1 gene expression was observed. Our results suggest that heat stress induces greater protein degradation and that methionine supplementation could induce protein deposition because methionine increased the expression of genes related to protein synthesis and decreased the expression of genes related to protein breakdown.

Growth hormone receptor gene expression in puberty.

The mechanisms regulating the synergic effect of growth hormone and other hormones during pubertal spurt are not completely clarified. We enrolled 64 females of Caucasian origin and normal height including 22 prepubertal girls, 26 pubertal girls, and 16 adults to evaluate the role of Growth Hormone/Insulin-like growth factor-I axis (GH/IGF-I) during the pubertal period. In these subjects both serum IGF-I and growth hormone binding protein levels, as well as quantitative growth hormone receptor (GHR) gene expression were evaluated in peripheral lymphocytes of all individuals by real-time PCR. Our results showed significantly lower IGF-I levels in women (148±10 ng/ml) and prepubertal girls (166.34±18.85 ng/ml) compared to pubertal girls (441.95±29.42 ng/ml; p<0.0001). Serum GHBP levels were significantly higher in prepubertal (127.02±20.76 ng/ml) compared to pubertal girls (16.63±2.97 ng/ml; p=0.0001) and adult women (19.95±6.65 ng/ml; p=0.0003). We also found higher GHR gene expression levels in pubertal girls [174.73±80.22 ag (growth hormone receptor)/5×10(5) ag (glyceraldehyde 3-phosphate dehydrogenase)] compared with other groups of subjects [women: 42.52±7.66 ag (growth hormone receptor)/5×10(5) ag (glyceraldehyde 3-phosphate dehydrogenase); prepubertal girls: 58.45±0.18.12 ag (growth hormone receptor)/5×10(5) ag (glyceraldehyde 3-phosphate dehydrogenase)], but the difference did not reach statistical significance. These results suggest that sexual hormones could positively influence GHR action, during the pubertal period, in a dual mode, that is, increasing GHR mRNA production and reducing GHR cleavage leading to GHBP variations.

GHR and IGF-I gene expression and production characteristics associated with GH gene polymorphism in Nile tilapia

The aim of this study was to investigate the effects of genotype on gene expression and performance characteristics in crossbred GIFT × Chitralada tilapia. We compared the effects of GH single band (GHsb) and GH double band (GHdb) genotypes on performance characteristics, growth hormone receptor (GHR) and insulin-like growth factor I (IGF-I) gene expression in the liver and white muscle. The experiment was conducted in a 2 × 2 factorial design with two categories of weight (20–35 g and 40–70 g) and two genotypes (GHsb and GHdb). Fin fragments were collected for genotyping, while the liver and white muscle samples were collected to analyze gene expression via qRT-PCR. GHdb genotype animals presented greater body weight, empty weight, weight of viscera, and filet weight and length, thereby indicating that GH variation may correlate with performance characteristics. Although some of the phenotypes we measured were correlated with genotype, we cannot say that it is due to the direct effect of the studied polymorphism. However, we recommend further studies be conducted to reveal the genetic nature of this polymorphism. • In this study a new polymorphism in GH gene was observed. • GH double band genotype animals presented the best characteristics of carcass. • GH double band genotype animals presented greater GHR mRNA expression.

Low calcium-phosphate diet attenuates dietary protein deficiency-mediated impairment of bone growth by blunting the decrease in serum IGF1 and in hepatic GH receptor gene expression

Low calcium-phosphate diet attenuates dietary protein deficiency-mediated impairment of bone growth by blunting the decrease in serum IGF1 and in hepatic GH receptor gene expression

Human metastatic melanoma cell lines express high levels of growth hormone receptor and respond to GH treatment

Accumulating evidence implicates the growth hormone receptor (GHR) in carcinogenesis. While multiple studies show evidence for expression of growth hormone (GH) and GHR mRNA in human cancer tissue, there is a lack of quantification and only a few cancer types have been investigated. The National Cancer Institute’s NCI60 panel includes 60 cancer cell lines from nine types of human cancer: breast, CNS, colon, leukemia, melanoma, non-small cell lung, ovarian, prostate and renal. We utilized this panel to quantify expression of GHR, GH, prolactin receptor (PRLR) and prolactin (PRL) mRNA with real-time RT qPCR. Both GHR and PRLR show a broad range of expression within and among most cancer types. Strikingly, GHR expression is nearly 50-fold higher in melanoma than in the panel as a whole. Analysis of human metastatic melanoma biopsies confirmed GHR gene expression in melanoma tissue. In these human biopsies, the level of GHR mRNA is elevated in advanced stage IV tumor samples compared to stage III. Due to the novel finding of high GHR in melanoma, we examined the effect of GH treatment on three NCI60 melanoma lines (MDA-MB-435, UACC-62 and SK-MEL-5). GH increased proliferation in two out of three cell lines tested. Further analysis revealed GH-induced activation of STAT5 and mTOR in a cell line dependent manner. In conclusion, we have identified cell lines and cancer types that are ideal to study the role of GH and PRL in cancer, yet have been largely overlooked. Furthermore, we found that human metastatic melanoma tumors express GHR and cell lines possess active GHRs that can modulate multiple signaling pathways and alter cell proliferation. Based on this data, GH could be a new therapeutic target in melanoma.

Short Communication Expression and Localization of Growth Hormone Receptor in the Oviduct of the Laying Hen (Gallus domesticus)

The purpose of the present study was to examine growth hormone receptor (GHR) gene expression by real-time PCR and demonstrate immunocytochemically the localization of GHR in four chicken oviductal parts, i.e. infundibulum, magnum, isthmus and shell gland. Experiments were carried out on Hy-Line laying hens decapitated 2 h after oviposition. GHR mRNA was expressed in all examined oviductal segments with a significantly lower level in the infundibulum in comparison to other parts of the oviduct. Specific GHR immunoreactivity was also detected in the wall of the oviduct. The intensity of the staining was as follows: infundibulum < or = isthmus < or = shell gland < or = magnum. In all oviductal parts, a positive reaction for GHR was observed in the mucosa whereas a very weak or no reaction was observed in the stroma. Within the mucosa a strong reaction for GHR was observed in the epithelium of the infundibulum and in the tubular gland of the magnum, isthmus and shell gland. Immunoreactivity for GHR was very weak in the mucosal epithelium of the magnum, isthmus and shell gland. In conclusion, the results point to the possibility of an important role of GH in oviduct functions in domestic hens.

Overview of Genomic Insights into Chicken Growth Traits Based on Genome- Wide Association Study and microRNA Regulation

Over the two past decades, a significant number of studies have observed animal growth traits to examine animal genetic mechanisms due to their ease of measurement and high heritability. Chicken which has a significant impact on fundamental biology is a major source of protein worldwide, making it an ideal model for examining animal growth trait development. The genetic mechanisms of chicken growth traits have been studied using quantitative trait loci mapping through genome-scan and candidate gene approaches, genome-wide association studies (GWAS), comparative genomic strategies, microRNA (miRNA) regulation of growth development analysis, and epigenomic analysis. This review focuses on chicken GWAS and miRNA regulation of growth traits. Several recently published GWAS reports showed that most genome-wide significant single nucleotide polymorphisms are located on chromosomes 1 and 4 in chickens. Chicken growth, particularly skeletal muscle growth and development, is greatly regulated by miRNA. Using dwarf and normal chickens, let-7b was found to be involved in determining chicken dwarf phenotypes by regulating growth hormone receptor gene expression.