Smart D, Forhead A J, Smith R F, Dobson H
Department of Veterinary Clinical Science, University of Liverpool, Neston, South Wirral, UK.
J Endocrinol. 1994 Sep;142(3):447-51. doi: 10.1677/joe.0.1420447.
The present study was designed to investigate whether transport, a mild environmental stressor, could affect the oestradiol-induced LH surge in postpartum ewes and, if so, the mechanism involved. Welsh Mountain ewes, with lambs removed at parturition (day 0) and hand-milked 12 and 48 h later, were given 50 micrograms oestradiol benzoate intramuscularly at various times postpartum. Blood samples were taken via an indwelling jugular venous catheter every 2 h from 8 to 24 h after oestradiol injection. All results are given as means +/- S.D. On day 1 oestradiol was unable to induce an LH surge in any ewe. Transport (10-14 h after oestradiol) delayed the onset of the oestradiol-induced LH surge on day 14 (17.5 +/- 1.7 vs 14.4 +/- 2.0 h, n = 5 each; P < 0.05), but not on day 28 (14.9 +/- 2.0 vs 14.0 +/- 2.4 h, n = 5 out of 7). Transport had no effect on the amplitude of the surge on either day. Naloxone treatment (1 mg/kg per 2 h) was unable to prevent the delay caused by transport (18.0 +/- 1.1 vs 17.5 +/- 1.7 h, n = 8 each), and did not affect the amplitude of the surge (28.4 +/- 5.3 vs 28.1 +/- 2.3 ng/ml, n = 8 each).(ABSTRACT TRUNCATED AT 250 WORDS)
本研究旨在调查运输这种轻度环境应激源是否会影响产后母羊中雌二醇诱导的促黄体生成素（LH）激增，若有影响，其涉及的机制是什么。威尔士山地母羊在分娩时（第0天）羊羔被带走，并在12小时和48小时后进行人工挤奶，在产后不同时间给它们肌肉注射50微克苯甲酸雌二醇。在注射雌二醇后8至24小时内，每隔2小时通过留置的颈静脉导管采集血样。所有结果均以平均值±标准差表示。在第1天，雌二醇无法在任何母羊中诱导LH激增。运输（在雌二醇注射后10 - 14小时）延迟了第14天雌二醇诱导的LH激增的开始时间（分别为17.5±1.7小时和14.4±2.0小时，每组n = 5；P < 0.05），但在第28天没有延迟（分别为14.9±2.0小时和14.0±2.4小时，7只中有5只）。运输对这两天激增的幅度均无影响。纳洛酮治疗（每2小时1毫克/千克）无法预防运输导致的延迟（分别为18.0±1.1小时和17.5±1.7小时，每组n = 8），且不影响激增的幅度（分别为28.4±5.3纳克/毫升和28.1±2.3纳克/毫升，每组n = 8）。（摘要截短为250字）
