Lin W W, Ramirez V D
Department of Physiology and Biophysics, University of Illinois, Urbana 61801.
J Reprod Fertil. 1991 Mar;91(2):531-42. doi: 10.1530/jrf.0.0910531.
Intact sexually mature New Zealand White male rabbits, raised under natural lighting and temperature conditions, were isolated and housed in air-conditioned quarters, in a 12-h light:12-h dark cycle. Push-pull cannulae were implanted towards the tuberal region of the hypothalamus, and animals were perfused with modified Krebs'-Ringer phosphate medium for an average period of 4 h. Most rabbits were repetitively perfused over an average period of 3.7 months. Perfusions were grouped into seasonal periods of about 40 or 80 days through the entire 1-year cycle: (A) 23 November to 31 December (winter solstice period: N = 6), (B) 1 January to 23 March (winter: N = 10), (C) 24 March to 13 June (spring: N = 9), (D) 14 June to 23 July (summer solstice period: N = 23), (E) 24 July to 13 October (late summer-early fall: N = 7) and (F) 14 October to 22 November (fall: N = 4). Maximal and minimal values of mean release, mean amplitude and mean frequency from every animal in each block were obtained. In the summer solstice group (D), maximal mean (+/- s.e.) LHRH release levels were significantly greater (14.42 +/- 6.62 pg/10 min) than for all groups (A, 0.76 +/- 0.27; B, 1.59 +/- 0.39; C, 1.34 +/- 0.22; E, 1.33 +/- 0.33; and F, 1.18 +/- 0.11) while during the winter solstice period (A), minimal mean LHRH release levels (0.48 +/- 0.04 pg/10 min) were significantly lower than in all other groups (B, 1.43 +/- 0.41; C, 0.96 +/- 0.11; D, 7.25 +/- 4.12; E, 1.18 +/- 0.37; and F, 1.18 +/- 0.11). Maximal values were highest during the summer solstice period while the minimal values were lowest during the winter solstice period. The amplitude and frequency of the LHRH pulses showed changes similar to those observed with the mean LHRH release. For 1 year, an estimated left testis weight was measured in 4-7 rabbits every 2-5 weeks. The percentage estimated testis weight peaked in early August and reached minimal levels during the winter months. These data demonstrate that the rabbit LHRH neural apparatus is very sensitive to seasonal influences although animals remained in a fixed photoperiod during the entire duration of the experiment.
将性成熟的新西兰白兔饲养在自然光照和温度条件下，然后将其隔离并安置在装有空调的房间内，光照周期为12小时光照：12小时黑暗。将推挽式套管植入下丘脑的结节区，并用改良的磷酸 Krebs-Ringer 培养基对动物进行灌注，平均灌注时间为4小时。大多数兔子在平均3.7个月的时间内进行了重复灌注。在整个1年周期内，灌注被分为约40天或80天的季节时段：(A) 11月23日至12月31日（冬至期：N = 6），(B) 1月1日至3月23日（冬季：N = 10），(C) 3月24日至6月13日（春季：N = 9），(D) 6月14日至7月23日（夏至期：N = 23），(E) 7月24日至10月13日（夏末初秋：N = 7）和(F) 10月14日至11月22日（秋季：N = 4）。获得每个时间段内每只动物的平均释放量、平均幅度和平均频率的最大值和最小值。在夏至组（D）中，最大平均（±标准误）促性腺激素释放激素（LHRH）释放水平（14.42±6.62 pg/10分钟）显著高于所有其他组（A，0.76±0.27；B，1.59±0.39；C，1.34±0.22；E，1.33±0.33；F，1.18±0.11），而在冬至期（A），最小平均LHRH释放水平（0.48±0.04 pg/10分钟）显著低于所有其他组（B，1.43±0.41；C，0.96±0.11；D，7.25±4.12；E，1.18±0.37；F，1.18±0.11）。最大值在夏至期最高，而最小值在冬至期最低。LHRH脉冲的幅度和频率变化与平均LHRH释放的变化相似。在1年的时间里，每2 - 5周对4 - 7只兔子测量一次估计的左侧睾丸重量。估计的睾丸重量百分比在8月初达到峰值，在冬季月份达到最低水平。这些数据表明，尽管在整个实验过程中动物处于固定的光照周期，但兔子的LHRH神经装置对季节影响非常敏感。
