Fennessy P F, Suttie J M, Crosbie S F, Corson I D, Elgar H J, Lapwood K R
MAFTech, Invermay Agricultural Centre, Mosgiel, New Zealand.
J Endocrinol. 1988 Apr;117(1):35-41. doi: 10.1677/joe.0.1170035.
Eight adult red deer stags were given an i.v. injection of synthetic gonadotrophin-releasing hormone (GnRH) on seven occasions at various stages of the antler cycle, namely hard antler in late winter, casting, mid-velvet growth, full velvet growth, antler cleaning and hard antler both during the rut and in mid-winter. The stags were allocated at random on each occasion to one of four doses, i.e. 1, 3, 10 or 95 micrograms GnRH. Blood samples were taken before GnRH injection and for up to 2 h after injection. Pituitary and testicular responses were recorded in terms of plasma LH and testosterone concentrations. There was an increase in plasma concentration of LH after the GnRH injection in all stags at all stages of the antler cycle. Dose-dependent responses of LH to GnRH in terms of area under the curve were apparent at all stages of the antler cycle. The lowest responses were recorded at casting, during velvet antler growth and at the rut sampling. The pattern of testosterone response reflected the inter-relationship of the antler and sexual cycles with very low testosterone responses occurring at casting and during velvet antler growth. The responses were higher at antler cleaning and then increased to a maximum at the rut before declining to reach their nadir at casting. The results are consistent with a hypothesis that the antler cycle, as a male secondary sexual characteristic, is closely linked to the sexual cycle and its timing is controlled by reproductive hormones. Low plasma concentrations of testosterone, even after LH stimulation, are consistent with the hypothesis that testosterone is unnecessary as an antler growth stimulant during growth.
八只成年雄性马鹿在鹿茸生长周期的不同阶段接受了七次静脉注射合成促性腺激素释放激素（GnRH），这些阶段分别是冬末硬角期、脱角期、鹿茸生长中期、鹿茸完全生长阶段、鹿茸清理期以及发情期和冬中期的硬角期。每次实验时，将这些雄鹿随机分配到四种剂量组之一，即1、3、10或95微克GnRH。在注射GnRH之前以及注射后长达2小时内采集血样。根据血浆促黄体生成素（LH）和睾酮浓度记录垂体和睾丸的反应。在鹿茸生长周期的所有阶段，所有雄鹿注射GnRH后血浆LH浓度均升高。在鹿茸生长周期的所有阶段，LH对GnRH的曲线下面积剂量依赖性反应均明显。脱角期、鹿茸生长期间和发情期采样时记录到的反应最低。睾酮反应模式反映了鹿茸和性周期的相互关系，脱角期和鹿茸生长期间睾酮反应非常低。鹿茸清理期反应较高，然后在发情期升至最高，之后下降，在脱角期降至最低点。这些结果与一个假设一致，即作为雄性第二性征的鹿茸生长周期与性周期密切相关，其时间由生殖激素控制。即使在LH刺激后，血浆睾酮浓度较低也与生长期间睾酮作为鹿茸生长刺激剂并非必需的假设一致。
