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Sakamoto K Yano T Kobayashi T Hagino A Aso H Obara Y 《Domestic animal endocrinology》2007,32(4):260-272
Growth hormone (GH) plays a specific role to inhibit apoptosis in the bovine mammary gland through the insulin-like growth factor (IGF)-I system, however, the mechanism of GH action is poorly understood. In this study, we show that GH dramatically inhibits the expression of IGFBP-5, and GH along with IGF-I enhanced the phosphorylation of Akt through the reduction of IGF binding protein (IGFBP)-5. To determine how GH affects Akt through IGF-I in bovine mammary epithelial cells (BMECs), we examined the phosphorylation of Akt in GH treated BMECs and found that IGF-I induced phosphorylation of Akt was significantly enhanced by the treatment with GH. We demonstrated that GH reduces mRNA and protein expression of IGFBP-5 in BMECs, but it does not affect the expression of IGFBP-3. To determine that the enhanced effect of the Akt phosphorylation by the treatment of GH is due to the inhibition of the expression of IGFBP-5, we examined the effect of IGFBP-3 and -5 on the phosphorylation of Akt through IGF-I in the GH-treated BMECs. The phosphorylation of Akt was inhibited in a dose-dependent manner when IGFBP-5 was added at varying concentrations and was also inhibited in the presence of IGFBP-3. The results of this study suggest that GH plays an important role on mammary gland involution in bovine mammary epithelial cells. 相似文献
2.
Wathes DC Cheng Z Bourne N Taylor VJ Coffey MP Brotherstone S 《Domestic animal endocrinology》2007,33(2):203-225
During the early postpartum period dairy cows mobilize fat and muscle to support lactation. This is associated with alterations in blood metabolite and hormone profiles which in turn influence milk yield and fertility. This study developed models to determine how metabolic traits, milk yield and body condition score were inter-related at different times in the periparturient period and to compare these relationships in primiparous (PP, n=188) and multiparous (MP, n=312) cows. Data from four previous studies which included information on blood metabolic parameters, parity, milk yield, body condition score and diet were collated into a single dataset. Coefficients of polynomial equations were calculated for each trait between -1 week pre-calving and week +7 postpartum using residual maximum likelihood modelling. The completed dataset was used in a multiple correlation model to determine how the best fit curves were related to each other over time. PP cows had higher concentrations of insulin-like growth factor-I and lower beta-hydroxybutyrate concentrations throughout, higher leptin concentrations pre-partum and both the peak in non-esterified fatty acids and the nadir in urea concentration occurred earlier after calving. These differences were associated with significantly lower milk production. Leptin concentrations fell at calving and were related to body condition score. Insulin was negatively correlated with yield in MP cows only. In MP cows the relationship between insulin-like growth factor-I and yield switched from negative to positive between weeks +4 and +7. Both beta-hydroxybutyrate and urea were positively related to yield in PP cows. In contrast, in MP cows beta-hydroxybutyrate was negatively correlated with yield and urea was strongly related to body condition score but not yield. These results suggest that there are differences in the control of tissue mobilization between PP and MP cows which may promote nutrient partitioning into growth as well as milk during the first lactation. 相似文献
3.
本试验旨在研究日粮色氨酸水平对生长猪的氮利用率以及对血浆类胰岛素生长因子-I(IGF-I)、生长激素(GH)、胰岛素浓度的影响。试验以4头大白去势公猪作为试验动物,以色氨酸含量分别为1.2、1.7、2.2和2.7g/kg的4种日粮为试验处理,按照4×4拉丁方进行试验设计。结果表明,色氨酸水平对干物质消化率、有机物消化率和氮消化率没有显著性影响(P>0.05)。氮沉积和氮的生物学利用率随着日粮色氨酸水平由1.2提高到1.7、2.2和2.7g/kg而显著提高(P<0.05),但是试验处理1.7、2.2和2.7g/kg之间的氮沉积和氮的生物学价值没有显著差异(P>0.05)。不同处理之间的血浆IGF-I、GH和胰岛素浓度没有显著差异(P>0.05)。日粮色氨酸水平和血浆IGF-I、GH或胰岛素浓度之间以及氮沉积和血浆IGF-I、GH或胰岛素浓度之间均无显著的相关关系(P>0.05)。综合以上结果,日粮色氨酸水平对生长猪的氮沉积具有显著影响,而对血浆IGF-I、GH和胰岛素没有显著影响。 相似文献
4.
The insulin-like growth factor I (IGF-I) cDNA (GenBank Accession No. AY247412) of triangular bream (Megalobrama terminalis) was expressed for the first time in Escherichia coli. To construct the expression plasmid, the IGF-I cDNA was subcloned into prokaryotic-expressing vector pGEX-4T-1. The E.coli JM109 was transformed with the recombinant plasmid pGEX-4T-1-IGF-I, and the transgene expression was observed after being induced with isopropyl-β-D-thiogalactoside (IPTG). The results of SDS polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting indicated that the recombinant fusion protein had immune activity and the molecular weight was about 47 kDa. The results of SDS-PAGE and thin layer scanning showed that the yield of fusion protein had been enlarged with prolonging time. When the time of induced expression was 1, 2, 3, 4, 5, and 6 h, the expression amount was approximately 1.4, 4.3, 8.1, 11.3, 16.3 and 18.8% of total bacterial protein respectively. 相似文献
5.
Insulin and IGF-I receptors and tyrosine kinase activity in carp ovaries: changes with reproductive cycle 总被引：2，自引：0，他引：2
J. Gutiérrez M. Párrizas N. Carneiro J. L. Maestro M. A. Maestro J. Planas 《Fish physiology and biochemistry》1993,11(1-6):247-254
Insulin and insulin-like growth factor I (IGF-I) receptors from carp ovaries were semipurified with wheat germ agglutinin at different moments of the reproductive cycle and their binding characteristics and tyrosine kinase activity were studied. Specific receptors for insulin and IGF-I were found. IGF-I receptors presented higher binding (23.8 ± 1.5%), number of receptors (965 ± 20fm/mg) and affinity (KD 0.24 ± 0.03nM) than those shown for insulin receptors (4.1 ± 1%, 530 ± 85fm/mg and 0.85 ± 0.1nM, respectively). Insulin and IGF-I receptors have a tyrosine kinase activity which is not different from that found in muscle of the same species. Seasonal changes were found in binding, with maximum values for insulin and IGF-I reached at the end of pre-spawning period (June). However, while IGF-I binding was observed in all stages, insulin binding decreased in autumn and disappeared in winter, which suggests a different role for the two peptides in ovarian physiology. 相似文献
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Growth hormone (GH) and reproduction: a review 总被引：5，自引：0，他引：5
Florence Le Gac Odile Blaise Alex Fostier Pierre-Yves Le Bail Maurice Loir Brigitte Mourot Claudine Weil 《Fish physiology and biochemistry》1993,11(1-6):219-232
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations. 相似文献
8.
The effects of dietary lysine on production performance,serum concentrations of metabolites,growth hormone （GH）,insulin-like growth factor-I （IGF-I） and IGF-I mRNA expression in growing rabbits were examined.One hundred weaned New Zealand rabbits were allocated to individual cages and randomly offered a diet containing 5.5 （L1）,6.5 （L2）,7.5 （L3）,8.5 （L4）,or 9.5 g （L5） lysine per kg diet.The results showed that the average daily gain （ADG） of the rabbits from L3,L4 or L5 was higher than those from L1 or L2 （P 〈 0.05）.The feed gain ratio （F/G） in the rabbits from L4 or L5 was lower than those from L1 or L2 （P 〈 0.05）.Dietary lysine did not affect serum concentrations of total protein （TP）,glucose,insulin （INS）,and growth hormone （GH） （P 〉 0.05）.The quadratic effects of lysine on the serum urea nitrogen （SUN） concentration was detected （P = 0.035）.Serum IGF-I concentrations had a trend to increase quadratically with the increasing dietary lysine （P = 0.07）.A significant correlation was found between serum IGF-I concentrations （x,ng mL-1） and ADG （y,g kg-1）： y = -0.017x2 ＋ 1.984x ＋ 20.87 （R2 = 0.8982,P = 0.003）.The relative abundance of hepatic and muscular IGF-I mRNA tended to increase with increasing dietary lysine levels （P = 0.053 and 0.082,respectively）.Providing the diets mainly consisted of corn,wheat bran and peanut vine,the most appropriate dietary lysine level for growing meat rabbits from weaning to 70 d old was found to be 8.5 g kg-1,and IGF-I may be an important factor controlling growth of weaned rabbits. 相似文献
9.
在4头门静脉、肝静脉、肠系膜静脉和股动脉上安装血管导管的绵羊中研究了克伦特罗（CL,0.8 mg/kgBW,肠系膜静脉给药,每天2次,连续5 d）对其肝脏生长代谢的影响。结果表明:CL对肝脏血流量影响较小。而在CL作用下绵羊血浆中尿素氮水平明显下降,肝静脉和门静脉血液尿素氮流量分别减少16.86％（P<0.01）和15.51％（P<0.05）。肝静脉多肽流量在CL处理期也较对照期下降38.71％（P<0.01）,门静脉处多肽水平处理期则与对照期相当。克伦特罗还增加绵羊肝脏IGF-I的合成和分泌,门静脉和肝静脉中的增加幅度分别为38.84％（P<0.01）和33.18％（P<0.01）。提示CL可通过增强对绵羊肝脏氮的储留及肝脏IGF-I的合成和分泌从而促进机体的生长代谢。 相似文献
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