Mondal Mohan, Rajkhowa Chandan, Prakash B S
Animal Endocrinology Laboratory, National Research Centre on Mithun (ICAR), Jharnapani, Medziphema, Via DIMAPUR, Nagaland-797 106, INDIA.
Reprod Biol. 2005 Jul;5(2):227-35.
To characterize the luteinizing hormone (LH) secretion patterns in growing mithun (Bos frontalis), a semi-wild ruminant, six female mithuns (1 year old; BW: 145.5 kg) were maintained in a semi-intensive system. Plasma progesterone (P(4)) level was measured in twice-a-week samples collected for six weeks to assess ovarian status. This was followed by a frequent sampling period. Blood samples collected at 15 min intervals for 9 h were assayed for plasma LH. Luteinizing hormone patterns consisted of pulses of varying amplitudes. Luteinizing hormone pulses occurred at an average rate of 0.54/h ( approximately 5 pulses/9 h). The rate did not differ among mithuns. The mean plasma LH levels was correlated with body weight (r=0.82; p<0.05) and pulse amplitude (r=0.87; p<0.01). Neither the LH amplitude nor the frequency was affected by time (p>0.05). The mean plasma P(4) concentration was 0.37 ng/ml. In conclusion, we demonstrated a pulsatile nature of LH secretion in growing mithuns. In addition, the mean plasma LH level and LH amplitude were positively correlated with body weight. It appears that in contrast to cattle, five LH pulses per nine hours recorded in mithuns were not an indication of approaching puberty.
为了描述半野生反刍动物成年米沙鄢水牛（Bos frontalis）促黄体生成素（LH）的分泌模式，将6头雌性米沙鄢水牛（1岁；体重：145.5千克）饲养在半集约化系统中。每周采集两次血样，持续六周，检测血浆孕酮（P(4)）水平，以评估卵巢状态。随后进入频繁采样期。每15分钟采集一次血样，持续9小时，检测血浆LH。促黄体生成素模式由不同幅度的脉冲组成。促黄体生成素脉冲的平均发生率为0.54次/小时（约5次脉冲/9小时）。不同米沙鄢水牛之间的发生率没有差异。血浆LH平均水平与体重（r=0.82；p<0.05）和脉冲幅度（r=0.87；p<0.01）相关。促黄体生成素的幅度和频率均不受时间影响（p>0.05）。血浆P(4)平均浓度为0.37纳克/毫升。总之，我们证明了成年米沙鄢水牛促黄体生成素分泌具有脉冲性。此外，血浆LH平均水平和LH幅度与体重呈正相关。与牛不同，米沙鄢水牛每9小时记录到5次促黄体生成素脉冲似乎并不表明即将进入青春期。
