Effects of GHR gene polymorphisms on growth and carcass traits in Zebu and crossbred beef cattle

The growth hormone receptor (GHR) is the cell surface receptor for growth hormone (GH) and is required for GH to carry out its effects on target tissues. The objectives of the present study were to estimate the allele and genotype frequencies of the GHR/Alu I gene polymorphism located in the regulatory region in beef cattle belonging to different genetic groups and to determine associations between this polymorphism and growth and carcass traits. Genotyping was performed on 384 animals, including 79 Nellore (Zebu), 30 Canchim (5/8 Charolais+3/8 Zebu), 30 Simmental X Nellore crossbred and 245 Angus x Nellore crossbred cattle. Alleles Alu I(+), Alu I(-) and Alu I(N)-null allele-were evidenced for the GHR/Alu I polymorphism and the frequency of the Alu I(N) allele was significantly higher than the frequency of the Alu I(+) and Alu I(-) alleles in all genetic groups. Genotype Alu I(N/N) of the GHRIAlu I predominated in Nellore animals, while the Alu I(N/+) and Alu I(N/-) predominated in the other genetic groups. In the association studies, traits of interest were analyzed using the General Linear Model (GLM) procedure of the SAS program and least squares means of the genotypes were compared by the Tukey test. Significant associations (P < 0.05) were observed between the Alu I(N/N) genotype of the GHRIAlu I polymorphism and lower weight gain and body weight at slaughter, although a confounding between genotypes and genetic groups may have occurred. (c) 2005 Elsevier B.V. All rights reserved.

Effects of polymorphic microsatellites in the regulatory region of IGF1 and GHR on growth and carcass traits in beef cattle

Growth hormone (GH), insulin-like growth factors 1 and 2 (IGF1 and IGF2) and their associated binding proteins and transmembrane receptors (GHR, IGF1R and IGF2R) play an important role in the physiology of mammalian growth. The objectives of the present study were to estimate the allele and genotype frequencies of microsatellite markers located in the 5'-regulatory region of the IGF1 and GHR genes in beef cattle belonging to different genetic groups and to determine effects of these markers on growth and carcass traits in these animals under an intensive production system. For this purpose, genotyping was performed on 384 bulls including 79 Nellore, 30 Canchim (5/8 Charolais + 3/8 Zebu) and 275 crossbred animals originating from crosses of Simmental (1/2 Simmental, n = 30) and Angus (1/2 Angus, n = 245) sires with Nellore females. The effects of substituting L allele for S allele of GHR microsatellite across Nellore, Canchim and 1/2 Angus were significant for weight gain and body weight (P < 0.05). The IGF1 microsatellite allele substitutions of 229 for 225 within Nellore group and of 225 for 229 within 1/2 Angus were not significant for any of the traits.

Association between IGF-I, IGF-IR and GHRH gene polymorphisms and growth and carcass traits in beef cattle

Molecular biology techniques are of help in genetic improvement since they permit the identification, mapping and analysis of polymorphisms of genes encoding proteins that act on metabolic pathways involved in economically interesting traits. The somatotrophic axis, which essentially consists of growth hormone releasing hormone (GHRH), growth hormone (GH), insulin-like growth factors I and II (IGF-I and IGF-II), and their associated binding proteins and receptors (GHRHR, GHR, IGF-IR and IGF-IIR), plays a key role in the metabolism and physiology of mammalian growth. The objectives of the present study were to estimate the allele and genotype frequencies of the IGF-I/SnaBI, IGF-IR/TaqI and GHRH/HaeIII gene polymorphisms in different genetic groups of beef cattle and to determine associations between these polymorphisms and growth and carcass traits. For this purpose, genotyping was performed on 79 Nellore animals, 30 Canchim (5/8 Charolais+3/8 Zebu) animals and 275 crossbred cattle originating from the crosses of Simmental (n=30) and Angus (n=245) sires with Nellore females. In the association studies, traits of interest were analyzed using the GLM procedure of SAS and least square means of the genotypes were compared by the Tukey test. Associations of IGF-I/SnaBI genotypes with body weight and subcutaneous backfat were significant (p < 0.05), and nearly significant for longissimus dorsi area (p=0.06), with the 1313 genotype being favorable compared to the AB genotype. No significant associations were observed between this polymorphism and weight gain or carcass yield (P > 0.05). The IGF-IR/TaqI and GHRH/HaeIII polymorphisms showed no association with production traits. (c) 2004 Elsevier B.V All rights reserved.

PDGF-B gene therapy accelerates bone engineering and oral implant osseointegration

Platelet-derived growth factor-BB (PDGF-BB) stimulates repair of healing-impaired chronic wounds such as diabetic ulcers and periodontal lesions. However, limitations in predictability of tissue regeneration occur due, in part, to transient growth factor bioavailability in vivo. Here, we report that gene delivery of PDGF-B stimulates repair of oral implant extraction socket defects. Alveolar ridge defects were created in rats and were treated at the time of titanium implant installation with a collagen matrix containing an adenoviral (Ad) vector encoding PDGF-B (5.5 x 10(8) or 5.5 x 10(9) pfu ml (1)), Ad encoding luciferase (Ad-Luc; 5.5 x 10(9) pfu ml (1); control) or recombinant human PDGF-BB protein (rhPDGF-BB, 0.3 mg ml (1)). Bone repair and osseointegration were measured through backscattered scanning electron microscopy, histomorphometry, microcomputed tomography and biomechanical assessments. Furthermore, a panel of local and systemic safety assessments was performed. Results indicated that bone repair was accelerated by Ad-PDGF-B and rhPDGF-BB delivery compared with Ad-Luc, with the high dose of Ad-PDGF-B more effective than the low dose. No significant dissemination of the vector construct or alteration of systemic parameters was noted. In summary, gene delivery of Ad-PDGF-B shows regenerative and safety capabilities for bone tissue engineering and osseointegration in alveolar bone defects comparable with rhPDGF-BB protein delivery in vivo. Gene Therapy (2010) 17, 95-104; doi: 10.1038/gt.2009.117; published online 10 September 2009

Growth factors and glucose homeostasis in diabetic rats: effects of exercise training

To investigate the alterations of glucose homeostasis and variables of the insulin-like growth factor-I (IGF- 1) growth system in sedentary and trained diabetic (TD) rats, Wistar rats were divided into sedentary control (SC), trained control (TC), sedentary diabetic (SD), and TD groups. Diabetes was induced by Alloxan (35 mg kg(-1) b.w.). Training program consisted of swimming 5 days week(-1), 1 h day(-1), during 8 weeks. Rats were sacrificed and blood was collected for determinations of serum glucose, insulin, growth hormone (GH), IGF-1, and IGF binding protein-3(IGFBP-3). Muscle and liver were removed to evaluate glycogen content. Cerebellum was extracted to determinate IGF-1 content. Diabetes decreased serum GH, IGF-1, IGFBP-3, liver glycogen, and cerebellum IGF-1 peptide content in baseline condition. Physical training recovered liver glycogen and increased serum and cerebellum IGF-1 peptide in diabetic rats. Physical training induces important metabolic and hormonal alterations that are associated with an improvement in glucose homeostasis and serum and cerebellum IGF-1 concentrations. Copyright (C) 2009 John Wiley & Sons, Ltd.

Association of GH and IGF-1 polymorphisms with growth traits in a synthetic beef cattle breed

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

HIPERTENSAO ARTERIAL EM PACIENTES OBESOS COM HIPERTROFIA CARDIACA. EFEITOS DO CAPTOPRIL SOBRE A SENSIBILIDADE A INSULINA E HORMONIO DE CRESCIMENTO

Purpose. To evaluate the effects of captopril (Cpt) on carbohydrate metabolism and growth hormone (GH) in adults hypertensive obese patients with normal (NGT) or impaired (IGT) glucose tolerance and left ventricular hypertrophy. Methods. Ten patients (53 ± 8 years), 8 women and 2 men, white, body mass index (BMI) ≥ 26 kg/m2, left ventricular mass index (LVMI) > 135 g/m2 in man and > 110 g/m2 in woman, with diastolic blood pressure (DBP) 95-115 mmHg after 3 weeks of placebo, were identified by oral glucose tolerance test (OGTT-75 g) as either with NGT or IGT, and treated with Cpt 25 mg t.i.d. for 8 weeks. At the 8 weeks, dosage was increased to 50 mg b.i.d. if DBP > 90 mmHg or the decrease of the DBP < 10%, during the next 8 weeks. OGTT and clonidine tests (0,04 mg/kg) with determinations, every 30 minutes of glucose, insulin, and GH during 2 hours, were performed. Results. Cpt lowered SBP and DBP in the NGT group and IGT group. The LVMI and the left ventricular mass (LVM) decreased in the IGT group with no significant change in the NGT group. Cpt promoted in the IGT group decrease in the area under the curve (AUC) of glucose, and AUC of insulin, with increase of the AUC of the percent of the β cell function, AUC of HC, and insulin sensitivity index with no significantly change in the NGT group. Conclusion. Adults hypertensive obese patients with IGT had decreased significantly in mean fasting level of GH concentrations compared to age, race, and BMI matched hypertensive patients with NGT. Treatment with Cpt induced a significant increased of the GH, with improvement of the metabolism in patients with IGT.

Efeito da somatotropina bovina recombinante no desempenho e nas características químicas da carne de bovinos

The objective of this study was to evaluate the effects of the use of recombinant bovine somatotropin (rbST) in weight gain, feeding efficiency and chemical characteristics of meat of young bulls. Fifty nine young bulls were used: 30 crossbred Simmental x Nelore and 29 Nelore aging between seven to eight months, weighing 236 and 116 kg, respectively. A randomized experiment in a 2 × 2 factorial arrangement was used. There were two levels of rbST (0 and 250 mg/animal/14 days) and two breed groups subdivided in two experimental phases. Diet was based on corn silage and concentrate aiming at a weight gain of 0.8 a day for Phase I (70 days) and 1.3 kg for Phase II (98 days). Animals were slaughtered at 13 months of age and the measurements of carcass dressing and meat quality were taken. Results showed that cross-breeding animals overcame (p<.01) the Nelore breed in weight gain and final weight at slaughtering. Use of rbST has not influenced weight gain, final weight, carcass weight and chemical characteristics of meat (p>.05). The use of rbST improved feeding efficiency 11.91 % for cross-bred and 24.32% for Nelore in Phase II.

Metabolic disturbances in male broilers of different strains. 2. Relationship between the thyroid and somatotropic axes with growth rate and mortality

Seven male broiler strains (Arbor Acres, Avian Farms, Cobb-500, Hubbard-Peterson, ISA, Naked Neck, and Ross) were compared for their growth rate, feed efficiency, and mortality due to sudden death and ascites. In addition, weekly plasma levels of thyroid hormones [3,3′,5-triiodothyronine (T3) thyroxine (T4), T3: T4 ratio, growth hormone (GH), and insulin-like growth factor-I (IGF-I)] were determined. The highly productive, commercial strains were very similar in their endocrine profiles but differed markedly from the Naked Neck chickens. Naked Neck chickens were characterized by higher plasma T3 and lower T4 levels at similar ages as well as when compared on the same body weight basis. The present findings support the hypothesis that the slightly hypothyroid state of high productive broilers renders them more sensitive to metabolic disorders. Naked Neck chickens also had higher plasma GH levels than those of their age-matched commercial broilers. The coefficient of variation for GH was highest for Naked Neck chickens, which is indicative for an amplified GH burst amplitude. It may be stated that changes in plasma thyroid hormone concentration in indirect response to selection for low feed conversion and fast growth may be causatively linked to susceptibility for metabolic disturbances such as sudden death syndrome and ascites.

Papel da eritropoetina recombinante humana sobre o metabolismo dos carboidratos, paratormônio, cálcio iônico, zinco, prolactina e níveis pressóricos em renais crônicos tratados com hemodiálise

Objective: To evaluate the influence of recombinant human erythropoietin (Epho) on carbohydrate metabolism, parathyroid hormone, calcium ionic, zinc, prolactin and blood pressure (BP) in chronic renal failure treated by hemodialysis. Methods: Ten patients in hemodialysis were followed during 24 weeks in two phases: 12 weeks pre-Epho (BP was measured pre and post hemodialysis sessions) and 12 weeks post-Epho (BP was measured as above and also the blood levels of glucose, insulin, parathyroid hormone, calcium ionic, prolactin, and zinc). Results: Patients were 39.8±8.5 y, 50% males. Hematocrit and hemoglobin presented a significant increase four weeks after Epho (22.3±2.3 to 28.1±2.6% and 7.4±0.8 to 9.4±0.9 g/dL, p<0.05). BP (mmHg) and weight pre-Epho: 158±99 and 59±13 (before hemodialysis), 147±96 and 55±13 (after hemo) and post-Epho: 161±100 and 59±13 (before hemo) 155±101 and 56±12 (after hemo) were all not statistically different in any moment. There are also no difference pre and post-Epho in fast glucose (91.8±6.5 and 90.8±6.1 mg/dL, p>0.05), parathyroid hormone (341.4±249.3 and 515.7±310 pg/ mL), calcium ionic (3,66±0.63 and 3.76±0.45 mmol/L), prolactin (males: 327±144.1 and 298.1 ±145.2 μg/mL; females: 666.2±426.6 and 659±395.3 μg/mL) and zinc (median of 0.73 and 0.71 μg\L). Basal insulin was lower after Epho (median of 9.1 to 3.8 μg/mL, p<0.05). Conclusion: These data suggest that recombinant human erythropoietin was effective to improve the anemia and the carbohydrate metabolism in patients with chronic renal failure treated by hemodialysis. © Copyright Moreira Jr. Editors. Todos os direitos reservados.

Daytime variations in glucose tolerance in people with impaired glucose tolerance

To determine whether glucose tolerance varies throughout the day in people with impaired glucose tolerance (IGT). We studied 15 healthy IGT, and 18 matched normal glucose tolerant (NGT) individuals. Blood samples were taken every 30-120 min during a 24 h period in which all individuals had three mixed meals and nocturnal sleep. We measured glucose, free fatty acids, specific insulin, intact proinsulin, cortisol and growth hormone. Variable responses were considered as concentrations and areas under the curves. Comparison between the groups was by Student's t-test, Mann-Whitney, and analysis of variance. Higher total glucose response, inappropriate normal total insulin response, and unproportionally increased proinsulin total response were observed in the IGT group. Lower glucose tolerance occurred in IGT after dinner, as in the NGT, and after breakfast associated with increased insulin response after breakfast, and similar proinsulin response after all three meals. IGT had higher glucose response than NGT after breakfast and lunch, similar insulin responses, and increased proinsulin-insulin ratio after all three meals. Data from this study demonstrate that IGT individuals present lower glucose tolerance in the evening, as those with NGT, and in the morning, as reported in patients with type 2 diabetes. © 2006 Elsevier B.V. All rights reserved.

Somatotropina bovina recombinante (rbST) e grupos raciais sobre a precocidade reprodutiva de cabras

The objective of this work was to evaluate the effect of rbST and breed group on the reproductive precocity of goat females. Eighteen goat females of Alpine breed and breed groups 1/2 Boer + 1/2 Alpine (1/2 BA) and 3/4 Boer + 1/4 Alpine (3/4 BA) were used, distributed in two homogeneous groups of 9 animals, received treatments: Group 1-0,3 mg of recombinant bovine somatotropin by kg of body weight each 14 days and Group 2 - control and aplication was subcutaneous. Animals from control group received saline solution in same dose and interval. The administration of hormone begins after weaning of animals (approximate 45 days of age). The train of the development of females was made by weighed weekly until reaching the previously definitive weight of 30 kg of live weight (LW). For evaluation of the reproductive performance it was made observations of the signals related to the oestrus. The characteristics evaluated was: Weight gain at born until weaning, weaning at 120 days, 150 and 180 days of age, weight to the oestrus, age to the rutting and the 30 age to kg of LW. It was not observed influence of growth hormone and the breed group for weight to rutting, age to rutting and age to reach 30 kg LW. The use of rbST in growth females did not modify the parameters of sexual precocity.

Influence of upper-body exercise order on hormonal responses in trained men

The aim of this study was to examine acute hormonal responses after different sequences of an upper-body resistance-exercise session. Twenty men completed 2 sessions (3 sets; 70% 1-repetition maximum; 2 min passive rest between sets) of the same exercises in opposite sequences (larger to smaller vs. smaller to larger muscle-group exercises). Total testosterone (TT), free testosterone (FT), testosterone/cortisol (T/C) ratio, sex-hormone-binding globulin (SHBG), growth hormone (GH), and cortisol (C) concentrations were measured before and immediately after each sequence. The results indicate that the GH concentration increased after both sessions, but the increase was significantly greater (p < 0.05) after the sequence in which larger muscle-group exercises were performed prior to the smaller muscle-group exercises. No differences were observed between sessions for TT, FT, SHBG, C, or the T/C ratio at baseline or immediately after resistance exercise. These results indicate that performing larger muscle-group exercises first in an upper-body resistance-exercise session leads to a significantly greater GH response. This may have been due to the significantly greater exercise volume accomplished. In summary, the findings of this investigation support the common prescriptive recommendation to perform larger-muscle group exercises first during a resistance-exercise session.

Relationship between cardiac autonomic regulation and auditory mechanisms: Importance for growth and development

The literature has already demonstrated that auditory stimulation with music influences the cardiovascular system. In this study, we performed a literature review in order to investigate the relationship between auditory mechanisms and cardiac autonomic regulation. The selected studies indicated that there is a strong correlation between noise intensity and vagal-sympathetic balance. Also, it was reported that music therapy improved heart rate variability in anthracycline-treated breast cancer patients. It was hypothesized that dopamine release in the striatal system induced by pleasure songs are involved in the cardiac autonomic regulation. Further studies are necessary to add new elements in the literature to improve new therapies to treat cardiovascular disorders.

Effect of glycerol on GHR and IGF-1 gene expression in breast muscle and on growth of Japanese meat quails

We evaluated messenger RNA (mRNA) expression of the growth-hormone (GHR) and insulin-like growth factor (IGF-1) genes in 28-day-old Japanese meat quails fed diets containing 0, 8, or 12% dietary glycerol in substitution of corn. Total RNA was extracted from the breast muscle and the DNA was amplified with specific primers using real-time PCR. Feed conversion ratio and feed intake were evaluated. The birds fed 8 and 12% glycerol presented higher IGF-1 mRNA expression [0.059 and 0.049 arbitrary units (AU), respectively] relative to those not fed with glycerol (0.029 AU), while 12% glycerol reduced GHR mRNA expression (0.022 AU). Dietary inclusion of 8% glycerol promoted similar performance results (feed conversion) as the diet with no glycerol. We conclude that inclusion of glycerol in the diet affects GHR and IGF-1 gene expression in Japanese meat quails. However, considering the performance results and the expression of the GHR and IGF-1 genes, 8% glycerol may be safely included in the diet of meat quails. © FUNPEC-RP.