Loureiro Bárbara, Ereno Ronaldo L, Favoreto Mauricio G, Barros Ciro M
Laboratory of Animal Reproductive Physiology, University of Vila Velha (UVV), Vila Velha, Espírito Santo, Brazil.
Department of Pharmacology, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil.
Theriogenology. 2016 Jul 15;86(2):523-7. doi: 10.1016/j.theriogenology.2016.02.001. Epub 2016 Feb 10.
Follicle population is important when animals are used in assisted reproductive programs. Bos indicus animals have more follicles per follicular wave than Bos taurus animals. On the other hand, B taurus animals present better fertility when compared with B indicus animals. Androgens are positively related with the number of antral follicles; moreover, they increase growth factor expression in granulose cells and oocytes. Experimentation was designed to compare testosterone concentration in plasma, and follicular fluid and androgen enzymes mRNA expression (CYP11A1, CYP17A1, 3BHSD, and 17BHSD) in follicles from Angus and Nellore heifers. Heifers were assigned into two groups according to the number of follicles: low and high follicle count groups. Increased testosterone concentration was measured in both plasma and follicular fluid of Angus heifers. However, there was no difference within groups. Expression of CYP11A1 gene was higher in follicles from Angus heifers; however, there was no difference within groups. Expression of CYP17A1, 3BHSD, and 17BHSD genes was higher in follicles from Nellore heifers, and expression of CYP17A1 and 3BHSD genes was also higher in HFC groups from both breeds. It was found that Nellore heifers have more antral follicles than Angus heifers. Testosterone concentration was higher in Angus heifers; this increase could be associated with the increased mRNA expression of CYP11A1. Increased expression of androgen-producing enzyme genes (CYP17A1, 3BHSD, and 17BHSD) was detected in Nellore heifers. It can be suggested that testosterone is acting through different mechanisms to increase follicle development in Nellore and improve fertility in Angus heifers.
在动物用于辅助生殖计划时，卵泡数量很重要。瘤牛动物每个卵泡波的卵泡比普通牛动物更多。另一方面，与瘤牛动物相比，普通牛动物的繁殖力更好。雄激素与腔卵泡数量呈正相关；此外，它们会增加颗粒细胞和卵母细胞中生长因子的表达。本实验旨在比较安格斯和内洛尔小母牛血浆中的睾酮浓度、卵泡液以及卵泡中雄激素酶mRNA表达（CYP11A1、CYP17A1、3BHSD和17BHSD）。根据卵泡数量将小母牛分为两组：低卵泡数组和高卵泡数组。安格斯小母牛的血浆和卵泡液中睾酮浓度均有所增加。然而，组内没有差异。安格斯小母牛卵泡中CYP11A1基因的表达更高；然而，组内没有差异。内洛尔小母牛卵泡中CYP17A1、3BHSD和17BHSD基因的表达更高，两个品种的高卵泡数组中CYP17A1和3BHSD基因的表达也更高。研究发现，内洛尔小母牛的腔卵泡比安格斯小母牛更多。安格斯小母牛的睾酮浓度更高；这种增加可能与CYP11A1 mRNA表达增加有关。在内洛尔小母牛中检测到雄激素生成酶基因（CYP17A1、3BHSD和17BHSD）的表达增加。可以推测，睾酮通过不同机制作用于内洛尔小母牛以促进卵泡发育，并提高安格斯小母牛的繁殖力。
