Stokkan K A, Sharp P J, Dunn I C, Lea R W
Department of Arctic Biology, University of Tromso, Norway.
Gen Comp Endocrinol. 1988 Apr;70(1):169-77. doi: 10.1016/0016-6480(88)90107-4.
Changes in plasma luteinizing hormone (LH), testosterone, thyroxine (T4), and triiodothyronine (T3) and the height of supraorbital combs were compared in captive willow ptarmigan (Lagopus lagopus lagopus) and Svalbard ptarmigan (Lagopus mutus hyperboreus) exposed to an artificial annual cycle of daylength simulating that at 70 degrees N. Plasma LH and testosterone and comb height increased more slowly in Svalbard than in willow ptarmigan as daylength increased. In both species, plasma LH and testosterone fell abruptly, and the supraorbital combs regressed in June, marking the development of long-day refractoriness. Comparison with free-living Svalbard ptarmigan (K.-A. Stokkan, P. J. Sharp, and S. Unander (1986) Gen. Comp. Endocrinol. 61, 446-451) at 80 degrees N, showed a similar slow increase in reproductive function before the onset of the breeding season. However, maximum plasma LH levels and comb size were higher in free-living than in captive Svalbard ptarmigan. Furthermore, long-day refractoriness developed earlier in captive than in free-living Svalbard ptarmigan. In both species of ptarmigan, the development of long-day refractoriness was associated with increased plasma prolactin. This increase was larger and occurred earlier in the Svalbard than in the willow ptarmigan. Seasonal changes in thyroid hormones were not as marked as for the other hormones measured. In both species, plasma T4 tended to increase and plasma T3 to decrease as daylength increased. A small increase in plasma T3 was seen after the development of long-day refractoriness in both species. It is concluded that captivity depresses the photoperiodic response of Svalbard ptarmigan more than that of willow ptarmigan.(ABSTRACT TRUNCATED AT 250 WORDS)
在圈养的柳雷鸟（Lagopus lagopus lagopus）和斯瓦尔巴德雷鸟（Lagopus mutus hyperboreus）中，比较了血浆促黄体生成素（LH）、睾酮、甲状腺素（T4）和三碘甲状腺原氨酸（T3）的变化以及眶上嵴的高度。这些鸟暴露于模拟北纬70度的人工年度日长周期中。随着日长增加，斯瓦尔巴德雷鸟的血浆LH、睾酮和眶上嵴高度的增加比柳雷鸟更缓慢。在这两个物种中，随着日长增加，血浆LH和睾酮在6月突然下降，眶上嵴退化，标志着长日照不应性的发展。与北纬80度的野生斯瓦尔巴德雷鸟（K.-A. Stokkan、P. J. Sharp 和 S. Unander（1986年）《普通比较内分泌学》61卷，446 - 451页）相比，在繁殖季节开始前，圈养的斯瓦尔巴德雷鸟的生殖功能也有类似的缓慢增加。然而，野生斯瓦尔巴德雷鸟的血浆LH最高水平和眶上嵴大小高于圈养的。此外，圈养的斯瓦尔巴德雷鸟比野生的更早出现长日照不应性。在这两种雷鸟中，长日照不应性的发展都与血浆催乳素增加有关。这种增加在斯瓦尔巴德雷鸟中更大且更早出现。甲状腺激素的季节性变化不如所测的其他激素明显。在这两个物种中，随着日长增加，血浆T4倾向于增加而血浆T3倾向于减少。在这两个物种出现长日照不应性后，血浆T3都有小幅增加。得出的结论是，圈养对斯瓦尔巴德雷鸟光周期反应的抑制比对柳雷鸟的抑制更大。（摘要截选至250词）
