Peticlerc D, Pelletier G, Lapierre H, Gaudreau P, Couture Y, Dubreuil P, Morisset J, Brazeau P
Agriculture Canada, Lennoxville, Quebec.
J Anim Sci. 1987 Oct;65(4):996-1005. doi: 10.2527/jas1987.654996x.
This study was undertaken to evaluate the biological potency of two synthetic human growth hormone-releasing factors, hGRF (1-44)NH2 and hGRF (1-29)NH2, on growth hormone (GH) release in young dairy heifers (n = 10) and pigs (n = 10). In each species, the GH response to an iv injection (0, .067, .2, .6 and 1.8 nmol.kg-1 body weight) of each peptide was evaluated in a double 5 X 5 Latin square design. In each square, there were five animals injected with either hGRF (1-44)NH2 or hGRF (1-29)NH2. Main effects were doses (n = 5) of hGRF and days (n = 5) of injection. In both species, data indicated that hGRF (1-44)NH2 and hGRF (1-29)NH2 equally stimulate GH secretion at all doses. In dairy heifers, average peak concentrations (81.7, 94.7, 84.5 and 93.7 ng.ml-1 vs 91.5, 81.0, 94.3 and 91.6 ng.ml-1) and area under the GH response curve (3,661, 4,541, 7,196 and 6,788 ng.ml-1.min vs 3,000, 3,982, 5,639 and 6,724 ng.ml-1.min) were not different (P greater than .05) between hGRF(1-44)NH2 and hGRF(1-29)NH2 at .067, .2, .6 and 1.8 nmol.kg-1, respectively. Similarly, in pigs, average peak concentrations (35.6, 38.6, 76.5 and 73.8 ng.ml-1 vs 28.7, 30.0, 41.3 and 80.8 ng.ml-1) and area under the GH curve (1,576, 1,567, 3,299 and 3,622 ng.ml-1.min vs 1,115, 1,658, 1,482 and 2,528 ng.ml-1.min) were not different (P greater than .05) between both peptides. A biphasic release of GH after hGRF (1-44)NH2 and hGRH (1-29)NH2 injection was observed at the highest dose in heifers. The GH response to hGRF injection was much more variable in pigs as compared with dairy heifers. In conclusion, hGRF (1-44)NH2 and its (1-29)NH2 fragment are equipotent in stimulating GH release in dairy heifers and pigs.
本研究旨在评估两种合成的人生长激素释放因子，即hGRF(1 - 44)NH₂和hGRF(1 - 29)NH₂，对青年奶牛（n = 10）和猪（n = 10）生长激素（GH）释放的生物学效能。在每个物种中，采用双5×5拉丁方设计评估每种肽静脉注射（0、0.067、0.2、0.6和1.8 nmol·kg⁻¹体重）后的GH反应。在每个方格中，有五只动物注射hGRF(1 - 44)NH₂或hGRF(1 - 29)NH₂。主要效应因素为hGRF的剂量（n = 5）和注射天数（n = 5）。在两个物种中，数据表明hGRF(1 - 44)NH₂和hGRF(1 - 29)NH₂在所有剂量下均能同等程度地刺激GH分泌。在奶牛中，hGRF(1 - 44)NH₂和hGRF(1 - 29)NH₂在0.067、0.2、0.6和1.8 nmol·kg⁻¹剂量下的平均峰值浓度（分别为81.7、94.7、84.5和93.7 ng·ml⁻¹对91.5、81.0、94.3和91.6 ng·ml⁻¹）以及GH反应曲线下面积（分别为3,661、4,541、7,196和6,788 ng·ml⁻¹·min对3,000、3,982、5,639和6,724 ng·ml⁻¹·min）无差异（P大于0.05）。同样，在猪中，两种肽的平均峰值浓度（分别为35.6、38.6、76.5和73.8 ng·ml⁻¹对28.7、30.0、41.3和80.8 ng·ml⁻¹）以及GH曲线下面积（分别为1,576、1,567、3,299和3,622 ng·ml⁻¹·min对1,115、1,658、1,482和2,528 ng·ml⁻¹·min）也无差异（P大于0.05）。在奶牛中，注射hGRF(1 - 44)NH₂和hGRH(1 - 29)NH₂后，在最高剂量下观察到GH的双相释放。与奶牛相比，猪对hGRF注射的GH反应变化更大。总之，hGRF(1 - 44)NH₂及其(1 - 29)NH₂片段在刺激奶牛和猪的GH释放方面具有同等效力。
