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1.
Mutations within the growth hormone receptor (GHR) gene that lead to an inactivated or truncated GHR protein cause abnormal growth and small adult size in a variety of species (Laron dwarfism). We studied a line of miniature Bos indicus cattle that have phenotypic (small mature size) and endocrine (increased blood growth hormone and decreased blood insulin-like growth factor-I concentrations) similarities to Laron dwarfs. Liver mRNA from miniature and control cattle was used to amplify a cDNA within the coding region of the GHR. The miniature cattle had GHR mRNA size (determined by Northern blot) and cDNA sequence that were similar to control cattle and, therefore, were unlike most Laron dwarf genotypes in which the GHR gene is mutated. Amounts of mRNA from liver as well as muscle (superficial neck and longissimus) were analyzed by ribonuclease protection assay for IGF-I, total GHR, GHR 1A (inducible, liver-specific GHR mRNA), and GHR 1B (constitutive GHR mRNA). Four control and five miniature bulls were tested. As expected, liver IGF-I mRNA was decreased in the miniature cattle (approximately 12% of control; P < 0.01). The amount of the total GHR as well as GHR 1A mRNA were also decreased in liver (17% and 19% of control, respectively; P < 0.01). Other GHR mRNA, including GHR 1B mRNA, were similar for miniature and control cattle. In muscle, there was a tendency (P < 0.10) for decreased IGF-I mRNA and increased GHR mRNA in miniature compared with control cattle. In summary, a novel phenotype for Laron dwarfism in Bos indicus cattle was associated with underexpression of GHR 1A mRNA, but not other GHR mRNA variants in liver. In addition to decreased GHR 1A mRNA, the miniature cattle had decreased liver IGF-I mRNA. Full expression of GHR 1A in liver, therefore, may be required for full liver IGF-I expression and normal growth.  相似文献   

2.
Mutations within the growth hormone receptor (GHR) gene that lead to an inactivated or truncated GHR protein cause abnormal growth and small adult size in a variety of species (Laron dwarfism). We studied a line of miniature Bos indicus cattle that have phenotypic (small mature size) and endocrine (increased blood growth hormone and decreased blood insulin-like growth factor-I concentrations) similarities to Laron dwarfs. Liver mRNA from miniature and control cattle was used to amplify a cDNA within the coding region of the GHR. The miniature cattle had GHR mRNA size (determined by Northern blot) and cDNA sequence that were similar to control cattle and, therefore, were unlike most Laron dwarf genotypes in which the GHR gene is mutated. Amounts of mRNA from liver as well as muscle (superficial neck and longissimus) were analyzed by ribonuclease protection assay for IGF-I, total GHR, GHR 1A (inducible, liver-specific GHR mRNA), and GHR 1B (constitutive GHR mRNA). Four control and five miniature bulls were tested. As expected, liver IGF-I mRNA was decreased in the miniature cattle (approximately 12% of control; P < 0.01). The amount of the total GHR as well as GHR 1A mRNA were also decreased in liver (17% and 19% of control, respectively; P < 0.01). Other GHR mRNA, including GHR 1B mRNA, were similar for miniature and control cattle. In muscle, there was a tendency (P < 0.10) for decreased IGF-I mRNA and increased GHR mRNA in miniature compared with control cattle. In summary, a novel phenotype for Laron dwarfism in Bos indicus cattle was associated with underexpression of GHR 1A mRNA, but not other GHR mRNA variants in liver. In addition to decreased GHR 1A mRNA, the miniature cattle had decreased liver IGF-I mRNA. Full expression of GHR 1A in liver, therefore, may be required for full liver IGF-I expression and normal growth.  相似文献   

3.
1. A study was carried out to evaluate the expression of growth hormone (GH), insulin-like growth factor I (IGF-I), mitochondrial adenine nucleotide translocase (ANT), cytochrome oxidase III (COX III) and avian uncoupling protein (avUCP) genes in 14-d-old Japanese quail that were fed different levels of glycerol (0%, 4%, and 12% dietary glycerol) which replaced maize as an energy source.

2. Total RNA was extracted from the breast muscle, and cDNA was amplified using real-time PCR with primers specific to the examined genes.

3. Quail fed the diet with 12% glycerol supplementation presented higher growth hormone (GH) mRNA expression than did those fed 0% glycerol. Supplementation with 12% glycerol negatively influenced IGF-I mRNA expression and reduced ANT mRNA expression in comparison with the treatment with no glycerol. COX III mRNA expression in the pectoralis superficialis muscle was decreased by 26% in quail fed 12% glycerol compared with those fed 0 and 4% glycerol.

4. There was no difference in UCP mRNA expression between quail fed 0 and 4% glycerol; however, UCP expression was reduced (73%) in birds fed the 12% glycerol diet compared with the level in those fed the 4% glycerol diet.

5. The inclusion of 4% glycerol in the diet produced results similar to those of the diet with no glycerol. Based on quail performance and the expression of the GH, IGF-I, ANT, COX III and UCP genes, 4% glycerol can be used in quail feeding without any harmful effects.  相似文献   


4.
This study examined the hypothesis that myostatin and PGC-1α are involved in the increase in skeletal muscle mass and transformation of fiber type in cold-exposed chicks. One-week-old chicks were exposed to acute (24 h) or long-term (8 d) cold at 4 °C or kept warm at 30 °C. Acute cold exposure induced a significant increase in the skeletal muscle weight and the ratio of slow- to fast-fiber specific troponin I expression (sTnI/fTnI), accompanied by a significant decrease in lactate dehydrogenase activity. Expression of myostatin mRNA in the muscle was significantly lower in cold-exposed chicks than in the controls, whereas PGC-1α mRNA expression was significantly enhanced. These changes in the gene expression rapidly returned to the levels of the control chicks after the end of cold exposure, whereas the changes in fiber type and enzymatic activity were not resumed within 24 h after removal of cold exposure. On the other hand, long-term exposure to cold resulted in a remarkable increase in skeletal muscle weight, accompanied by a significant increase in the ratio of sTnI/fTnI and the enzymatic activities of cytochrome oxidase and lactate dehydrogenase. However, the expression level of myostatin mRNA in cold-exposed chicks was not different from that in their age-matched control chicks and that of PGC-1α mRNA was significantly lower than in the controls. These results indicate that myostatin and PGC-1α expression in the skeletal muscle rapidly change in response to acute cold, suggesting the possibility that these two genes could be involved in the increase in muscle mass and transformation of fiber type, respectively, at the initial stage of adaptation in cold-exposed chicks.  相似文献   

5.
The effects of fasting on insulin-like growth factor (IGF)-I, IGF-II, and IGF-binding protein (IGFBPs) mRNA in channel catfish were examined. Fed control fish (Fed) were compared to fish that had been fasted for 30 d followed by 15 d of additional feeding (Restricted). Sequence alignment and similarity to orthologous proteins in other vertebrates provided structural evidence that the 3 catfish sequences identified in the present research were IGFBP-1, -2, and -3. Prolonged fasting (30 d) reduced body weight approximately 60% (P < 0.001) and decreased IGF-I mRNA in the liver and muscle (P < 0.01). Fifteen days of re-feeding restored concentrations of hepatic and muscle IGF-I mRNA. Liver IGF-II mRNA was not affected by fasting but was increased 2.2-fold after 15 d of re-feeding (P < 0.05). Abundance of muscle IGF-II mRNA was similar between the fed control group and the restricted group throughout the experimental period. Fasting also increased liver IGFBP-1 mRNA (P < 0.05) and decreased IGFBP-3 mRNA (P < 0.01), whereas abundance of IGFBP-2 mRNA was not significantly affected. Interestingly, re-feeding for 15 d did not restore concentrations of IGFBP-1 and IGFBP-3 mRNA relative to fed control concentrations. The IGF results suggest that IGF-I and IGF-II are differently regulated by nutritional status and probably have a differential effect in promoting muscle growth during recovery from fasting. Similar to mammals, IGFBP-1 mRNA in catfish is increased during catabolism, whereas IGFBP-3 mRNA is decreased during inhibited somatic growth. The IGFBP results provide additional evidence of the conserved nature of the IGF-IGFBP-growth axis in catfish.  相似文献   

6.
Exposure to high temperatures during the summer renders pigs susceptible to severe heat stress. Our previous studies found that pig small intestine epithelial tissue became significantly damaged following exposure to heat stress, negatively affecting body weight gain. The deleterious effects of heat stress could be ameliorated using a traditional Chinese medicine decoction (CMD), sustaining normal growth while under heat stress. In the current study, we hypothesized the mechanism of CMD activity to be via regulation of gut hormones (NPY, MLN, SCT and GCG) secretion from endocrine cells, which are responsible for nutrient digestion and absorption. To test this, 36 Chinese experimental mini-pigs (2 months of age) were screened according to weight and litter origin, and divided into three treatment groups: control (23 °C for 24 h + standard feed), heat stress (HS; 26 °C for 19 h, 40 °C for 5 h + standard feed) and CMD (26 °C for 19 h, 40 °C for 5 h + standard feed supplemented with CMD); n = 12 per group. Feed intake and body weight gain were measured daily. Pigs were euthanized at days 1 and 6 after initial treatment with blood and sections of small intestine epithelial tissue collected. Serum cortisol (Cor) concentrations were determined using RIA. Endocrine cell number and structural analysis were performed using silver staining, and gut hormone secretion examined by microarray. Dietary supplementation with CMD significantly improved porcine growth performance (P < 0.05), decreased the Cor levels (P < 0.01), increased endocrine cell number as well as up-regulating neuropeptide Y (NPY), motilin (MLN) and secretin (SCT) and down-regulating glucagon (GCG) expression in pig jejunum on day 6 when compared with the HS group. Taken together, our results indicate CMD supplementation can significantly reduce the negative effects of heat stress on pig jejunum, maintaining growth performance similar to non-heat stressed animals. CMD's activity appears to be via adjusting gut hormone secretion to regulate metabolism and improve animal growth.  相似文献   

7.
Photoperiod manipulation, specifically a long-day photoperiod (LDPP), increases milk production in lactating cattle. We have previously reported that the galactopoietic effect of LDPP is associated with an increase in circulating IGF-I, which seems to occur independently of changes in concentrations of GH, IGFBP-2, and IGFBP-3. This study tested the hypothesis that LDPP increases the expression of GH receptor (GHR) 1A messenger RNA (mRNA) in the liver. Two groups of Holstein steer calves (98 +/- 4 d old) were maintained indoors and exposed to LDPP (16-h light: 8-h dark; n = 6) or short-day photoperiod (SDPP; 8-h light: 16-h dark; n = 6) for 60 d. Calves were individually fed a grain- and alfalfa-based diet. Jugular blood samples were collected weekly and via cannula at 15-min intervals for a 4-h period on d 1, 26, and 55 of the study to monitor pulsatile hormone secretion. Serum was harvested and assayed for IGF-I, prolactin (PRL), and GH using RIA. Liver biopsies were obtained at 3-wk intervals to quantify changes in hepatic IGF-I and GHR 1A mRNA using real-time PCR. Steer BW increased during the study but did not differ between treatments. No differences in ADG or total DMI were observed. Relative to SDPP, calves on LDPP had higher (P < 0.05) serum IGF-I concentrations. Concentrations of PRL increased (P < 0.01) in calves exposed to LDPP compared with calves exposed to SDPP. Differences (P < 0.05) in pulsatile GH secretion were also detected. Hepatic IGF-I and GHR 1A mRNA were positively correlated with circulating IGF-I concentrations, and although both increased with time, they were not affected by photoperiod treatment. These results confirm that LDPP increases circulating concentrations of IGF-I, but this occurs independently of changes in IGF-I synthesis and GHR 1A mRNA expression in the liver. Therefore, our hypothesis that LDPP increases the expression of GHR 1A mRNA in the bovine liver is rejected.  相似文献   

8.
蓝塘仔猪IGF-1水平与组织IGF-1、GHR基因的表达   总被引：4，自引：5，他引：4  
32头不同日龄(出生、3、21、35d)蓝塘仔猪,由前腔静脉采血后剖杀,取肝脏、背最长肌样品。用RIA法测血液、组织中IGF 1浓度,用放射受体法(RBA)检测肝脏、肌肉组织中GHR结合活性,用实时荧光定量PCR法检测IGF 1、GHRmRNA的表达水平。结果表明:(1)血液中IGF 1在出生日显著高于其它时期(P<0 05)。肌肉组织中IGF 1含量高于肝脏组织,肌肉组织IGF 1含量在3、21、35日龄时都显著高于出生日(P<0 05)。(2)肝脏细胞膜GHR结合活性在出生日显著高于3、21日龄(P<0 05),肝脏细胞膜GHR结合活性高于肌肉组织。(3)肝脏组织IGF 1、GHRmRNA的表达量均显著高于肌肉组织(P<0 05)。肝脏IGF 1mRNA的表达在出生日、21日龄时显著高于3、35日龄(P<0 05),GHRmRNA的表达在出生日显著高于其它日龄(P<0 05)。肌肉IGF 1、GHRmRNA的表达在出生日均显著高于其它日龄(P<0 05)。  相似文献   

9.
The aim of this study was to evaluate the effects of dietary betaine (BET) on growth performance, redox state, and related gene expression in broilers under heat stress (HS). A total of 144 21-day-old male broiler chickens with similar body weights were assigned randomly to three treatments with six replicates (eight chickens per replicate cage). Broilers in the control (CON) group were kept at thermoneutral (TN, 22±1°C) conditions and fed a basal diet until they were 42 days of age. Broilers in the other two groups (defined as HS and HS + BET) were exposed to HS (34±1°C, 8 h/day) and fed the basal diet without or with 1000 mg/kg BET, respectively. Rectal and cockscomb temperature of broilers was increased (P<0.05) in HS and HS + BET groups compared with the CON group, whereas there was no difference between HS and HS + BET groups. Dietary BET supplementation restored (P<0.05) average daily gain (ADG) and average daily feed intake (ADFI) of broilers and reversed (P<0.05) the increase in serum alanine transaminase (ALT) activity and malondialdehyde (MDA) content in the liver tissue of broilers under HS. The HS + BET group had higher (P<0.05) activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) in the liver tissue and mitochondria than the HS group, and the same pattern was observed for glutathione (GSH) and GSH/glutathione disulphide (GSSG) in the liver tissue. The decreased mRNA levels of GPX1 and uncoupling protein (UCP) in the liver induced by HS were restored by BET supplementation. In conclusion, dietary BET supplementation can alleviate HS-induced hepatic and mitochondrial oxidative damage of broilers by regulating mRNA expressions of GPX1 and UCP.  相似文献   

10.
To evaluate the effect of maternal leptin on muscle growth, we injected 0 μg (control, CON), 0.5 μg (low leptin dose, LL) or 5.0 μg (high leptin dose, HL) of recombinant murine leptin dissolved in 100 μl of PBS into the albumen of broiler eggs prior to incubation. The newly hatched chicks were all raised under the same conditions until 21 days of age (D21), when body weight was measured and samples of gastrocnemius muscle were collected and weighed. Myosin ATPase staining was applied to identify myofibre types and measure the cross‐sectional area (CSA) of myofibres. Real‐time PCR was performed to quantify leptin receptor (LEPR), insulin‐like growth factor 1 (IGF‐1), IGF‐1 receptor (IGF‐1R), growth hormone receptor (GHR) and myostatin (MSTN) mRNA expression in the gastrocnemius muscle. The activity of calpains (CAPNs) in the gastrocnemius muscle was measured using a quantitative fluorescence detection kit. Male chickens treated with both high and low doses of leptin had significantly higher (p < 0.05) body weight on D21. The high leptin significantly increased the CSA (p < 0.05) of gastrocnemius muscle in male chickens, which coincided with a 93% increase (p < 0.05) in IGF‐1 mRNA expression. Likewise, the LL dose increased the weight of gastrocnemius muscle in male chickens (p < 0.05), which was accompanied by a 41% down‐regulation (p < 0.05) of MSTN mRNA expression and a decreased activity of CAPNs. However, all these changes were not observed in female chickens. The proportion of myofibre types did not altered. No significant change was detected for LEPR and GHR mRNA expression. These results indicate that in ovo leptin treatment affects skeletal muscle growth in chickens in a dose‐dependent and sex‐specific manner. The altered expression of IGF‐1, MSTN mRNA and activity of CAPNs in skeletal muscle may be responsible for such effects.  相似文献   

11.
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12.
Exposure to cold increases abundance of mRNA for uncoupling protein-3 (UCP3) in skeletal muscle, whereas the influence of exposure to heat is unknown. Thus, we conducted a study to investigate the influence of heat exposure on UCP3 mRNA abundance in porcine skeletal muscle. Three pigs aged 110 to 120 d, with an average BW of 75 kg, from each of eight litters were used. Each littermate was assigned to one of three treatment groups; one group was reared at 32 degrees C and fed ad libitum (32AL) for 4 wk, whereas the other two groups were maintained at 23 degrees C for the same period, and either pair-fed the intake of their 32AL littermates (23PF), or fed ad libitum (23AL). The RNase protection assay revealed that UCP3 mRNA abundance in longissimus dorsi and rhomboideus muscles was higher (P < 0.05) in the 32AL group than the 23PF group. The 23AL group also had significantly higher UCP3 mRNA abundance than the 23PF group in these muscles. Plasma total 3,5,3'-triiodothyronine concentration of the 32AL group was lower (P < 0.05) than that of the 23PF group, whereas mRNA abundance of thyroid hormone receptor (TR) isoforms, TRalpha1 and TRalpha2, in these muscles was not affected, suggesting that the 32AL group was in a relatively hypo-thyroid state. Because thyroid hormone up-regulates UCP3 expression, these results indicate that factors other than thyroid hormone may play a role in regulating UCP3 mRNA abundance in skeletal muscle of heat-exposed pigs.  相似文献   

13.
为研究持续不同时间的冷、热应激对猪孤雌胚胎体外发育的影响,本研究以猪孤雌胚胎为材料,采用免疫荧光染色、实时荧光定量PCR技术检测不同时间的冷（31℃）、热应激（41℃）处理对猪孤雌胚胎发育后囊胚发育率、细胞数、细胞凋亡率、自噬相关基因及细胞凋亡相关基因mRNA转录水平的影响。结果显示,热应激12 h后囊胚发育率显著低于对照组（P<0.05）,冷应激18 h后囊胚发育率显著低于对照组（P<0.05）,而冷应激组囊胚发育率高于热应激组。热应激12 h和冷应激18 h后均导致囊胚内细胞数显著低于对照组（P<0.05）,细胞凋亡率显著高于对照组（P<0.05）,且冷应激组的细胞凋亡率低于热应激组。冷、热应激组自噬相关蛋白LC3的表达均高于对照组;冷、热应激中自噬相关基因Atg6和Atg8的表达均极显著高于对照组（P<0.01）,Lamp2基因的表达均显著高于对照组（P<0.05）,热应激组中的Atg6和Atg8基因的表达高于冷应激组。通过检测细胞凋亡相关基因mRNA的转录水平发现,冷、热应激组中细胞凋亡相关基因Bak、Casp-3、Fas的表达均极显著高于对照组（P<0.01）,Bcl-xl基因的表达均显著低于对照组（P<0.05）。综上,猪孤雌胚胎对冷应激（31℃）的耐受性比对热应激（41℃）强,且热应激可诱导体外培养的猪孤雌胚胎自噬及凋亡相关基因的表达,从而降低孤雌胚胎发育的能力。  相似文献   

14.
Cows with different Insulin-like Growth Factor-I (IGF-I) concentrations showed comparable expression levels of hepatic growth hormone receptor (GHR). Suppressor of cytokine signaling 2 (SOCS2), could be responsible for additional inhibition of the GHR signal cascade. The aims were to monitor cows with high or low antepartal IGF-I concentrations (IGF-Ihigh or IGF-Ilow), evaluate the interrelationships of endocrine endpoints, and measure hepatic SOCS2 expression. Dairy cows (n = 20) were selected (240 to 254 days after artificial insemination (AI)). Blood samples were drawn daily (day -17 until calving) and IGF-I, GH, insulin, thyroid hormones, estradiol, and progesterone concentrations were measured. Liver biopsies were taken (day 264 ± 1 after AI and postpartum) to measure mRNA expression (IGF-I, IGFBP-2, IGFBP-3, IGFBP-4, acid labile subunit (ALS), SOCS2, deiodinase1, GHR1A). IGF-I concentrations in the two groups were different (p < 0.0001). However, GH concentrations and GHR1A mRNA expression were comparable (p > 0.05). Thyroxine levels and ALS expression were higher in the IGF-Ihigh cows compared to IGF-Ilow cows. Estradiol concentration tended to be greater in the IGF-Ilow group (p = 0.06). It was hypothesized that low IGF-I levels are associated with enhanced SOCS2 expression although this could not be decisively confirmed by the present study.  相似文献   

15.
研究蛋鸭热应激条件下不同组织中热休克蛋白70(HSP70)基因mRNA表达规律,为揭示蛋鸭热应激反应机理提供参考。60只绍兴蛋鸭25℃饲养20d,其中30只进行40℃热应激处理1h,采取荧光定量PCR方法分别测定不同组织中HSP70mRNA的表达水平。试验组与对照组相比,肝脏、脾脏和胰腺组织HSP70mRNA表达差异不显著,其他6种组织HSP70基因表达量均有不同程度的增加,试验组心脏、腿肌、垂体、下丘脑、胸肌、肾脏中HSP70基因表达量分别高于对照组3.6倍、2.8倍、2.7倍、2.4倍、2.2倍和1.57倍。  相似文献   

16.
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17.
为了阐明不同营养水平限制饲养妊娠期母羊后,在不同生长阶段对蒙古绵羊生长激素受体(GHR)mRNA表达水平的影响,研究根据GenBank中绵羊的GHR序列,设计1对预计扩增产物为395 bp的引物,采用RT-PCR技术检测了蒙古绵羊在不同营养水平条件下肝脏和背最长肌中GHR mRNA表达量的变化。结果表明:在限制采食阶段,低营养水平组即营养限制组(RG1组)和阈值组(RG2组)肝脏的GHR mRNA表达水平低于正常营养的对照组(CG组),而背最长肌的GHR mRNA表达水平高于对照组,说明限制营养对绵羊GHR水平的影响具有组织特异性。在补偿生长结束阶段,RG1组和RG2组绵羊的肝脏和背最长肌中GHR mRNA表达水平均恢复到对照组水平。  相似文献   

18.
The present work on Bubalus bubalis (buffalo) was designed to study heat shock protein 70 (HSP70) induction in lymphocytes, its purification and characterization. HSP70 induction and expression kinetics at different temperatures and time durations were also studied. HSP70 purification was carried out by immunoaffinity chromatography using adenosine di-phosphate (ADP-agarose column) and the characterization of the purified protein was done using western blotting by mouse monoclonal anti-HSP70. The molecular weight of HSP70 of buffalo lymphocytes was found to be approximately of 68 kDa and was less than that of bovine brain HSP70. The purified HSP70 was assessed using indirect inhibition enzyme-linked immunosorbent assay (ELISA). A good amount of HSP70 (1430 ηg HSP70/100 μl) was recovered after purification, out of the total 2040.40 ηg of HSP70/100 μl of cell supernatant. To assess the impact of temperature and time dependent variability in the induction and expression pattern of HSP70, buffalo lymphocytes were subjected to three different temperature treatments, viz.: (I) 38 °C for 48 h and further exposed the same cells at 45 °C for 3 h, (II) 42 °C for 3 h, and (III) 45 °C for 3 h, respectively. The respective cell viability was found to be 68%, 63%, and 51%. The HSP70 levels were 58.30 ± 4.37, 42.59 ± 9.04 and 21.95 ± 6.79 ng/million cells, respectively, at three temperature exposures. The results indicates that higher intensity and duration of temperature exposure cause higher HSP70 induction in buffalo lymphocytes to maintain cellular homeostasis with a threshold of thermal dose for maximum HSP70 expression. However immediate induction of HSP70 in the lymphocytes was dependent on magnitude of thermal exposure (stress level) and time of thermal exposure (stress duration). The present study on HSP70 and its induction will help likely to solve the problems related to the present scenario of thermo-adaptability in buffaloes.  相似文献   

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