Effects of testosterone on pedicle formation and its transformation to antler in castrated male, freemartin and normal female red deer (Cervus elaphus)
Effects of testosterone on pedicle formation and its transformation to antler in castrated male, freemartin and normal female red deer (Cervus elaphus)
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DOI：
10.1016/s0016-6480(02)00625-1
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发表时间：
2003-03-01
影响因子：
2.7
通讯作者：
Suttie, JM
中科院分区：
文献类型：
--
作者：
Li, C;Littlejohn, RP;Suttie, JM
花梗和鹿角是公鹿的第二性征。因此，这些结构的发育是在雄激素的控制下。椎弓根生长是由血浆睾酮（T）水平的增加和升高引起的，而当T水平降低时，第一个鹿茸从完全形成的椎弓根转化。在开始生茸前阉割，会使以后的生茸和生茸失效。母鹿也有可能发展的蒂和鹿角，但他们通常不表达这种表型，由于缺乏足够的雄激素刺激。以往的研究表明，雌性白尾鹿可以很容易地诱导生长的花梗以及鹿角通过单一的外源性雄激素（EA），但在红鹿（马鹿）单一或不规则的EA处理只能刺激阉割的男性，正常或卵巢切除的女性生长的花梗，但不是鹿角。本研究的目的是测试这些EA诱导的红鹿的花梗是否未能产生鹿角，是因为它们在组成上不能这样做，还是因为在这些先前的研究中使用的雄激素治疗没有达到在完整的雄鹿中自然表现出的血浆T曲线。本研究中使用了8只去势红鹿公鹿、3只自由马鹿（与雄性双胞胎出生的雌性）和3只正常雌性红鹿，并进行了EA治疗，每两周注射一次用于去势或作为植入物用于自由马鹿和雌性，直到蒂生长的后期。每两周采集一次血样，用于分析血浆T和IGF 1浓度。结果表明，通过常规电针治疗和随后在鹿蒂生长后期停药，成功地模拟了实验鹿的自然血浆T曲线。所有去势的雄性、2/3的自由马鹿和1/3的正常雌性红鹿不仅形成了花梗，而且还形成了鹿角。基于这些结果，我们得出结论，EA诱导的花梗至少在红鹿属鹿，像那些在属Odocoileus，是组成能够产生鹿角，如果他们有足够的高度。(C)2003 Elsevier Science（美国）。All rights reserved.
Pedicles and antlers are male deer secondary sexual characters. As such, development of these structures is under the control of androgen hormones. Pedicle growth is caused by increasing and elevated plasma testosterone (T) levels, whereas first antler transformation from a fully formed pedicle occurs when the T levels are decreasing. Castration prior to pedicle initiation abrogates future pedicle and antler formation. Female deer also have the potential to develop pedicles and antlers, but they do not normally express this phenotype due to lack of sufficient androgen stimulation. Previous studies have shown that female white-tailed deer could be readily induced to grow pedicles as well as antlers by singular administration of exogenous androgens (EA), but in red deer (Cervus elaphus) singular or irregular EA treatment could only stimulate castrated male, normal or ovariectomised females to grow pedicles, but not antlers. The present study was set out to test whether these EA-induced pedicles in red deer failed to give rise to antlers was because they were constitutively incapable of doing so, or because the plasma T profile naturally exhibited in intact stags was not achieved by the androgen treatment used in these previous studies. Eight castrated red deer stag calves, 3 freemartins (females which were born co-twin to males), and 3 normal female red deer were used in the present study and treated with EA, either as biweekly injections for the castrates or as implants for freemartin and females until the late stage of pedicle growth. Blood sampling was carried out biweekly for the analyses of plasma T and IGF1 concentration. The results showed that the natural plasma T profile in the experimental deer was successfully mimicked through regular EA treatment and subsequent withdrawal at late pedicle growth stage. All castrated males, 2 out of 3 freemartin, and 1 out of 3 normal female red deer formed not only pedicles, but also antlers. Based on these results, we conclude that EA-induced pedicles at least in red deer of the genus Cervus, like those in the genus Odocoileus, are constitutively capable of giving rise to antlers, if they are of sufficient height. (C) 2003 Elsevier Science (USA). All rights reserved.