Songsasen N, Nagashima J, Thongkittidilok C
Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA, USA.
Reprod Domest Anim. 2017 Apr;52 Suppl 2:29-34. doi: 10.1111/rda.12858. Epub 2017 Jan 22.
Canid reproduction is unique among other mammals in that females experience long and variable periods of ovarian inactivity. While the domestic dog exhibits a non-seasonal, largely sporadic monoestrus occurring once or twice a year, most wild canids, such as the gray wolf (Canis lupus) and red wolf (Canis rufus), are seasonal breeders with onset apparently dependent on species, latitudinal location and/or variety of environment factors. Neuroendocrine controls of ovarian functions have been mostly studied in the dog, but less so in their wild counterparts, due to difficulties in regular blood sampling. Yet, development of non-invasive hormone monitoring has advanced the understanding of reproductive cycle in wild canids. Recent advances in in vitro follicle culture technology also have begun to provide insights into paracrine controls of canid ovarian folliculogenesis. This review highlights current knowledge on canid reproduction with emphasis on endocrine and paracrine controls of follicular development. We also discuss future research priorities, including advancing the understanding of anoestrous termination and role of paracrine factors in canine folliculogenesis.
犬科动物的繁殖在其他哺乳动物中独具特色，因为雌性会经历长时间且多变的卵巢静止期。家犬表现为非季节性、大多为偶发性的单次发情，每年发生一到两次，而大多数野生犬科动物，如灰狼（Canis lupus）和红狼（Canis rufus），是季节性繁殖者，发情开始显然取决于物种、纬度位置和/或多种环境因素。卵巢功能的神经内分泌控制大多在犬类中进行了研究，但在其野生同类中研究较少，这是由于定期采血存在困难。然而，非侵入性激素监测技术的发展增进了我们对野生犬科动物生殖周期的了解。体外卵泡培养技术的最新进展也开始为犬科动物卵巢卵泡发生的旁分泌控制提供见解。本综述重点介绍了犬科动物繁殖的当前知识，着重于卵泡发育的内分泌和旁分泌控制。我们还讨论了未来的研究重点，包括加深对发情终止以及旁分泌因子在犬类卵泡发生中作用的理解。
