Testosterone Levels in Male Formosan Reeve's Muntjac: Uncoupling of the Reproductive and Antler Cycles

摘要

Cervid species are generally assumed to be seasonal in their reproductive activity, and species that develop antlers also do so in a seasonal manner in conjunction with this annual puberty. As gonadotropin endocrine support for reproductive activity wanes, the resultant lowered testosterone levels initiate antler casting. Male Formosan Reeve's muntjac (Muntiacus reeves micrurus) exhibits an annular antler cycle with growth initiating in early May, velvet shedding and antler hardening by early Sept.,and casting the following May. This cycle was correlated with fluctuating testosterone levels in a manner somewhat similar to that observed in other cervids. However, this species remains reproductively active year-round with spermatozoa present in the testes and epididymides, with no variation in their quantity or quality. These findings suggest that the testosterone threshold required for antler development in this muntjac may be set higher than that required for spermatogenesis, or conversely, that spermatogenesis might be controlled by other hormones in addition to testosterone. http://zoolstud.sinica.edu.tw/Journals/48.1/120.pdf