Kraeling R R, Marple D N, Rampacek G B, Rahe C H, Sartin J L
J Anim Sci. 1987 Jun;64(6):1690-5. doi: 10.2527/jas1987.6461690x.
Five ovariectomized (OVX) gilts were placed in each of two chambers at 20 C with a photoperiod of 12 h light and 12 h dark for 8 d (12L:12D). On d 1, blood samples were collected via jugular cannula every 30 min from 0830 to 1630. At 1630, 200 micrograms of thyrotropin releasing hormone (TRH) were injected iv and blood samples taken every 10 min for 1 h and every 30 min for the next 2 h. On d 2, samples were taken every 30 min from 0830 to 0930 and from 1530 to 1630. Temperature was changed to 10 C or 30 C on d 3. Samples were taken from 0830 to 1630 on d 3, 4 and 9. At 1630 on d 9, the TRH challenge was repeated. Mean basal serum concentrations of prolactin (PRL) were similar for all gilts and for all periods. However, serum PRL response (ng PRL X ml-1 X 150 min-1) to TRH increased (P less than .0001) after exposure to 30 C, while exposure to 10 C failed to alter PRL response. In Exp. 2, six ovariectomized gilts were assigned to each chamber. The protocol of Exp. 1 was followed through d 3, except temperature and photoperiod were changed to 10 C and 8L:16D or 30 C and 16L:8D. On d 34 the TRH challenge was repeated. Mean basal serum concentration of PRL was similar for all gilts and all periods. However, simultaneous increases in temperature and photoperiod increased (P less than .005) serum PRL response to TRH, whereas simultaneous decreases in temperature and photoperiod failed to alter PRL response to TRH.
将5头卵巢切除（OVX）的小母猪置于两个实验舱中，温度为20℃，光照周期为12小时光照和12小时黑暗，持续8天（12L:12D）。在第1天，从0830至1630每隔30分钟通过颈静脉插管采集血样。1630时，静脉注射200微克促甲状腺激素释放激素（TRH），随后1小时内每隔10分钟采集血样，接下来2小时内每隔30分钟采集血样。在第2天，从0830至0930以及1530至1630每隔30分钟采集样本。在第3天，温度变为10℃或30℃。在第3天、第4天和第9天从0830至1630采集样本。在第9天1630时，重复TRH激发试验。所有小母猪在所有时间段的平均基础血清催乳素（PRL）浓度相似。然而，暴露于30℃后，血清PRL对TRH的反应（ng PRL×ml-1×150分钟-1）增加（P＜0.0001），而暴露于10℃未能改变PRL反应。在实验2中，将6头卵巢切除的小母猪分配到每个实验舱。遵循实验1的方案至第3天，不同的是温度和光照周期变为10℃和8L:16D或30℃和16L:8D。在第34天重复TRH激发试验。所有小母猪在所有时间段的平均基础血清PRL浓度相似。然而，温度和光照周期同时增加会增加（P＜0.005）血清PRL对TRH的反应，而温度和光照周期同时降低未能改变PRL对TRH的反应。
