Bartŏs L, Schams D, Kierdorf U, Fischer K, Bubenik G A, Siler J, Losos S, Tománek M, Lastovková J
Research Institute of Animal Production, CZ-104 00 Praha 10-Uhríneves, Czech Republic.
J Endocrinol. 2000 Jan;164(1):87-95. doi: 10.1677/joe.0.1640087.
We studied the role of androgens in antler growth. In particular, we investigated whether the onset of antler regrowth is triggered by a short-term pulse of testosterone and if low levels of androgens are required for antler growth. The study was conducted on 12 surgically castrated fallow deer bucks (Dama dama) aged approximately 27 months. Six animals (CA group) were given the antiandrogen, cyproterone acetate (CA, 1000 mg/treatment); the others were given vehicle solution only (control). Before each CA treatment, blood was sampled and analysed for testosterone, androstenedione, IGF-1, cortisol, FSH, and LH. CA treatment and blood sampling were performed 2 days before castration, on the day of castration and afterwards at 2-day intervals until day 22. Subsequently, CA treatment and blood sampling continued at weekly intervals until day 270. All animals cast their antlers, followed by antler regrowth in all control bucks, but in only four of the six CA-treated castrates. Plasma testosterone concentrations were low in all animals (between 0.01 and 0.20 ng/ml), but were significantly (P<0001) greater in the controls. In both groups, a temporary increase in testosterone values was recorded around the time of antler regrowth, the peak being significantly (P<0.01) higher in the controls. Androstenedione showed a similar pattern as testosterone. Plasma IGF-1 concentrations increased sharply during the antler growth spurt and did not differ significantly between the two groups throughout the study period. Cortisol concentrations were greater in controls than in the CA group. However, no link with the antler cycle was apparent. FSH and LH concentrations were higher in the controls for most of the study. Antlers produced by the control bucks were significantly larger than those in the CA group (P<0.03). For antler length, testosterone, androstenedione and IGF-1, areas under the curve (AUC) were calculated over the period of antler growth. For the pooled deer (n=12) significant correlations existed between AUCs of antler length and testosterone, but not for antler length and IGF-1. Also, a trend for a positive correlation between AUCs of antler length and androstenedione was noted. It is concluded that a plasma androgen concentration at least above a minimal threshold level is a necessary prerequisite for normal antler regrowth in fallow deer, and that this androgen effect is not mediated via circulating IGF-1. The biological role of low levels of androgens may be to sensitize antler cells to the stimulating effect of IGF.
我们研究了雄激素在鹿茸生长中的作用。具体而言，我们调查了鹿茸再生的开始是否由睾酮的短期脉冲触发，以及鹿茸生长是否需要低水平的雄激素。该研究以12只年龄约27个月、经手术去势的黇鹿雄鹿（黇鹿）为对象。6只动物（CA组）给予抗雄激素药物醋酸环丙孕酮（CA，1000mg/次治疗）；其他动物仅给予赋形剂溶液（对照组）。每次CA治疗前，采集血液样本并分析睾酮、雄烯二酮、胰岛素样生长因子-1（IGF-1）、皮质醇、促卵泡生成素（FSH）和促黄体生成素（LH）。在去势前2天、去势当天以及之后每隔2天直至第22天进行CA治疗和血液采样。随后，CA治疗和血液采样继续每周进行一次，直至第270天。所有动物均脱角，随后所有对照雄鹿的鹿茸均再生，但6只接受CA治疗的去势雄鹿中只有4只的鹿茸再生。所有动物的血浆睾酮浓度均较低（在0.01至0.20ng/ml之间），但对照组的浓度显著更高（P<0.001）。两组在鹿茸再生时均记录到睾酮值的暂时升高，对照组的峰值显著更高（P<0.01）。雄烯二酮呈现出与睾酮相似的模式。血浆IGF-1浓度在鹿茸生长高峰期急剧增加，且在整个研究期间两组之间无显著差异。对照组的皮质醇浓度高于CA组。然而，与鹿茸周期无明显关联。在研究的大部分时间里，对照组的FSH和LH浓度更高。对照雄鹿长出的鹿茸显著大于CA组（P<0.03）。对于鹿茸长度、睾酮、雄烯二酮和IGF-1，计算了鹿茸生长期间的曲线下面积（AUC）。对于合并的鹿（n=12），鹿茸长度的AUC与睾酮之间存在显著相关性，但鹿茸长度与IGF-1之间不存在显著相关性。此外，还注意到鹿茸长度的AUC与雄烯二酮之间有正相关趋势。结论是，血浆雄激素浓度至少高于最低阈值水平是黇鹿正常鹿茸再生的必要前提，且这种雄激素作用不是通过循环IGF-1介导的。低水平雄激素的生物学作用可能是使鹿茸细胞对IGF的刺激作用敏感。
