Finnerty M, Enright W J, Morrison C A, Roche J F
Teagasc, Grange Research Centre, Dunsany, Co Meath, Ireland.
J Reprod Fertil. 1994 Jul;101(2):333-43. doi: 10.1530/jrf.0.1010333.
Bull calves were immunized with GnRH analogue-human serum albumin (HSA-Cys-Gly-GnRH) conjugate to determine the effects of dose, adjuvant type and interval between primary and booster injections on plasma testosterone and LH concentrations, and testes and body growth. Friesian bull calves aged between 8 and 10 weeks (n = 72) were blocked according to age and weight and, within block, randomly assigned to 12 treatment combinations (n = 6 per treatment combination) in a 3 x 2 x 2 factorial plan. Main effects were (i) conjugate dose (0.0, 0.1 or 1.0 mg HSA-Cys-Gly-GnRH), (ii) adjuvant (diethylaminoethyl-dextran or non-ulcerative Freund's adjuvant), and (iii) interval between primary (day 0) injection and booster injection (day 28 or 56). Plasma testosterone and LH concentrations and antibody titres were determined in blood samples collected at 14 day intervals during the experiment (140 days). Testicular measurements were taken in situ every 28 days. Antibody titres (% binding at 1:160 dilution) were > or = 10% 28 days after booster injection and remained high for 140 days in 47 of 48 GnRH-immunized bulls. The mean titre was higher (P < 0.05) in response to the 1.0 mg dose compared with the 0.1 mg dose (37.7% versus 29.6% binding, respectively; pooled SED 2.55%). Mean LH and testosterone concentrations were reduced (P < 0.05) in immunized animals compared with controls. However, the 1.0 mg dose decreased mean testosterone concentrations by a greater extent (P < 0.001) than either the 0.1 mg or 0.0 mg doses. Testes length and depth, and scrotal circumference were decreased (P < 0.001) in immunized animals compared with controls; however, the 1.0 mg dose decreased (P < 0.001) testes parameters to the greatest extent. There was no effect of conjugate dose on average daily gain in body mass. It is concluded that (i) dose of conjugate, type of adjuvant and interval between primary and booster injections affected antibody titres, (ii) the use of 0.1 or 1.0 mg of HSA-Cys-Gly-GnRH decreased LH and testosterone concentrations, and testicular development throughout the experiment, without adversely affecting body growth, and (iii) an effective protocol is 1.0 mg GnRH-HSA conjugate, given in the adjuvant diethylaminoethyl dextran, with a primary-booster interval of 56 days.
用促性腺激素释放激素（GnRH）类似物与人血清白蛋白（HSA-Cys-Gly-GnRH）的偶联物对公牛犊进行免疫，以确定剂量、佐剂类型以及初次注射和加强注射之间的间隔对血浆睾酮和促黄体生成素（LH）浓度、睾丸及身体生长的影响。将8至10周龄的弗里斯兰公牛犊（n = 72）按年龄和体重进行分组，并在组内按照3×2×2析因设计随机分配至12种处理组合（每种处理组合n = 6）。主要因素包括：（i）偶联物剂量（0.0、0.1或1.0 mg HSA-Cys-Gly-GnRH）；（ii）佐剂（二乙氨基乙基葡聚糖或非溃疡性弗氏佐剂）；（iii）初次注射（第0天）和加强注射之间的间隔（第28天或56天）。在实验期间（140天），每隔14天采集血样，测定血浆睾酮和LH浓度以及抗体滴度。每28天对睾丸进行一次原位测量。在48头接受GnRH免疫的公牛中，47头在加强注射后28天抗体滴度（1:160稀释时的结合百分比）≥10%，并在140天内保持较高水平。与0.1 mg剂量相比，1.0 mg剂量的平均滴度更高（P < 0.05）（结合率分别为37.7%和29.6%；合并标准误2.55%）。与对照组相比，免疫动物的平均LH和睾酮浓度降低（P < 0.05）。然而，1.0 mg剂量比0.1 mg或0.0 mg剂量更显著地降低了平均睾酮浓度（P < 0.001）。与对照组相比，免疫动物的睾丸长度、深度和阴囊周长减小（P < 0.001）；然而，1.0 mg剂量对睾丸参数的降低程度最大（P < 0.001）。偶联物剂量对体重平均日增重没有影响。研究得出以下结论：（i）偶联物剂量；佐剂类型以及初次注射和加强注射之间的间隔影响抗体滴度；（ii）使用0.1或1.0 mg的HSA-Cys-Gly-GnRH在整个实验过程中降低了LH和睾酮浓度以及睾丸发育，且对身体生长没有不利影响；（iii）有效的方案是1.0 mg GnRH-HSA偶联物，用二乙氨基乙基葡聚糖佐剂给药，初次-加强间隔为56天。
