Long-term rhythms of testicular volume and plasma prolactin concentrations in rams reared for 3 years in constant photoperiod.
Long-term rhythms of testicular volume and plasma prolactin concentrations in rams reared for 3 years in constant photoperiod.
复制标题
恒定光周期饲养3年公羊睾丸体积和血浆催乳素浓度的长期节律。
DOI：
10.1530/jrf.0.0650439
复制
发表时间：
1982
期刊：
影响因子：
--
通讯作者：
N. B. Haynes
中科院分区：
文献类型：
--
作者：
C. Howles;J. Craigon;N. B. Haynes
从4至38月龄，将两组6只公羊保持在由短日照（8 h光照（L）：16 h黑暗（D）; S组）和长日照（16 h L：8 h D; L组）组成的恒定光周期下。另外5只公羊在代表自然发生的光周期下饲养（N组）。每周测量睾丸大小和血浆催乳素浓度。这些数据进行了时间序列分析。结果表明，在测量的两个参数中存在持续的周期性偏移。在N组中，睾丸体积和血浆催乳素的平均周期长度约为1年，血浆催乳素的峰值先于睾丸体积的峰值约18周。从L组公羊也表现出这些参数的节律性变化，周期约为35周，这表明，这些周期性变化可能构成真正的内源性circannual节奏;再次催乳素峰值之前的睾丸体积约18周。总体而言，S组公羊的睾丸生长波动幅度与L组相似，但变化规律性低于L组。S组血浆催乳素显著低于L组，几乎没有节律性证据。根据N组和L组催乳素峰值和睾丸体积之间的时间关系，提出催乳素可能在公羊生殖周期的时间安排中发挥作用。
Two groups of 6 rams were kept under constant photoperiod consisting of short days (8 h light (L): 16 h dark (D); Group S) and long days (16 h L:8 h D; Group L) from 4 to 38 months of age. Five other rams were reared under a photoperiod representative of that occurring naturally (Group N). Testis size and plasma prolactin concentrations were obtained weekly. These data were subjected to time series analysis. The results indicated that there were persistent periodic excursions in both parameters measured. In Group N, the average cycle length for both testis volume and plasma prolactin was about 1 year and the peaks in plasma prolactin preceded those in testis volume by about 18 weeks. Rams from Group L also showed rhythmical changes in these parameters with periodicities of around 35 weeks and it is suggested that these cyclic changes may constitute true endogenous circannual rhythms; again the prolactin peaks preceded those of testis volume by about 18 weeks. Overall, rams from Group S had excursions of testis growth of a similar magnitude to those of Group L but the changes were less regular than those of Group L. Plasma prolactin was significantly lower in Group S than in Group L and there was little evidence for rhythmicity. It is proposed on the basis of the temporal relationship between peaks of prolactin and testis volume in Groups N and L, that prolactin may play a role in the timing of the reproductive cycle in the ram.