Buonomo F C, Klindt J, Yen J T
Animal Sciences Division, Monsanto Co., St. Louis, MO 63198, USA.
J Anim Sci. 1995 May;73(5):1318-26. doi: 10.2527/1995.7351318x.
Differences in endocrine and metabolic responses to porcine somatotropin administered by daily injection or sustained-release implant (pST-SR) have been previously observed in genetically lean and obese, gilts and barrows. The current study extended those findings by examining responses to pST-SR in gilts and boars of a contemporary crossbred line, as well as lean and obese lines. Pigs were treated with 0, 1, or 2 pST-SR implants inserted subcutaneously behind the ear. The osmotically driven pST-SR implants delivered 2 mg of recombinant pST/d. Pigs were bled on d 0, 7, 14, 28, and 42 after implantation. Sera were assayed for pST, insulin-like growth factor (IGF)-I, IGF-II, IGF-binding protein-2 (IGFBP-2), insulin, glucose, and blood urea nitrogen (BUN). Circulating pST concentrations were increased in a dose-dependent manner (P < .001) in the pST-SR treated pigs, but remained elevated (P < .05) only in the 4 mg of pST-SR/d group on d 42. Significant effects of line, dose, time, line x dose, and time x dose were noted for IGF-I. Serum IGF-I was elevated in a dose-dependent manner over the 42-d period in all pST-treated swine. Examination of the line x dose x time interaction indicated that the IGF-I response to pST-SR was greatest in the obese line compared with the lean and crossbred lines. Conversely, serum IGF-II responded to pST-SR to the least extent in the obese pigs. Circulating IGFBP-2 concentrations were reduced by pST-SR, but were not affected by line. The BUN concentrations were reduced by pST-SR. An interaction of line x dose x time (P < .001) indicated that the response was greater in the obese line. Line x dose x time interactions were also noted for insulin and glucose concentrations, which were elevated by pST-SR in a dose-response manner in all lines, but to a much greater extent in the obese pigs.(ABSTRACT TRUNCATED AT 250 WORDS)
先前已观察到，每日注射或缓释植入猪生长激素（pST-SR）时，遗传上瘦型和肥胖型的后备母猪和公猪在内分泌和代谢反应上存在差异。当前研究通过检测当代杂交品系以及瘦型和肥胖型品系的后备母猪和公猪对pST-SR的反应，扩展了这些发现。给猪皮下植入0、1或2个pST-SR植入物进行处理。渗透驱动的pST-SR植入物每天释放2毫克重组pST。在植入后第0、7、14、28和42天采集猪血样。检测血清中的pST、胰岛素样生长因子（IGF）-I、IGF-II、IGF结合蛋白-2（IGFBP-2）、胰岛素、葡萄糖和血尿素氮（BUN）。pST-SR处理的猪中，循环pST浓度呈剂量依赖性增加（P <.001），但仅在第42天，每日4毫克pST-SR组中仍保持升高（P <.05）。对于IGF-I，品系、剂量、时间、品系×剂量和时间×剂量有显著影响。在所有pST处理的猪中，血清IGF-I在42天期间呈剂量依赖性升高。对品系×剂量×时间相互作用的检测表明，与瘦型和杂交品系相比，肥胖型品系中IGF-I对pST-SR的反应最大。相反，肥胖猪中血清IGF-II对pST-SR的反应程度最小。pST-SR使循环IGFBP-2浓度降低，但不受品系影响。pST-SR使BUN浓度降低。品系×剂量×时间的相互作用（P <.001）表明肥胖型品系中的反应更大。胰岛素和葡萄糖浓度也存在品系×剂量×时间的相互作用，pST-SR使所有品系中的胰岛素和葡萄糖浓度呈剂量反应性升高，但在肥胖猪中升高幅度更大。（摘要截断于250字）
