The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Domest Anim Endocrinol. 2021 Jan;74:106515. doi: 10.1016/j.domaniend.2020.106515. Epub 2020 Jun 26.
Estradiol-17β (E2) and progesterone (P4) regulate oviductal functions, providing a suitable environment for the transport and maturation of gametes, fertilization, and embryonic development. In addition to the E2 and P4 nuclear receptors, estrogen receptor (ESR) α and β, nuclear progesterone receptor (PGR), nongenomic mechanisms through G protein-coupled estrogen receptor (GPER1), and progesterone receptor membrane component (PGRMC) 1 and 2 mediate E2 and P4 actions. This study aimed to characterize the local endocrine environment of the oviduct by examining the oviductal E2 and P4 concentrations and their receptors' mRNA expression during the periovulatory phase. The bovine oviducts were collected in a slaughterhouse and the days postovulation were estimated according to state of the ovaries and the uterus. Samples of the ampulla and isthmus ipsilateral and contralateral to the preovulatory follicle or corpus luteum were collected on Days 19 to 21, Days 0 to 1, Days 2 to 4, and Days 5 to 7 of the estrous cycle. The effects of the estrous cycle phase and oviductal region (ampulla and isthmus) and side (ipsilateral and contralateral) were analyzed by 3-way ANOVA. Moreover, to clarify the regulatory mechanisms of the mRNA expression of hormone receptors, the effects of E2 and P4 on mRNA expression in the oviduct were examined by multiple linear regression. The oviductal endocrine milieu on Days 19 to 21 was characterized by an E2-dominant environment with high E2 and low P4, high ESR1 and PGR mRNA expression, and low ESR2, GPER1, and PGRMC2 mRNA expression, whereas the corresponding on Days 0 to 1 was characterized by the endocrine milieu without hormone dominance. The environment on Days 2 to 4 and Day 5 to 7 was characterized by opposite tendency of oviductal hormone concentrations and their receptors' mRNA expression to Days 19 to 21. Additionally, the ipsilateral oviduct had the more P4-dominant endocrine milieu, with lower E2 and higher P4 concentrations, and different expression of ESR1/2, GPER1, PGR, and PGRMC2 mRNA when compared with the contralateral oviduct on Days 2 to 4 and Days 5 to 7, except for PGRMC1. Although oviductal E2 and P4 influenced the mRNA expression of ESR1/2, GPER1, PGR, and PGRMC1/2, their effects were different between regions and sides. In summary, the oviductal endocrine milieu varies according to the estrous cycle phase and the oviductal region and side, which may be involved in the estrous cycle phase-specific and oviductal region-specific and side-specific functions.
雌二醇-17β（E2）和孕酮（P4）调节输卵管功能，为配子的运输和成熟、受精和胚胎发育提供适宜的环境。除了 E2 和 P4 核受体、雌激素受体（ESR）α和β、核孕酮受体（PGR）、通过 G 蛋白偶联雌激素受体（GPER1）的非基因组机制以及孕酮受体膜成分（PGRMC）1 和 2 介导 E2 和 P4 的作用。本研究旨在通过检查促排卵期间输卵管中 E2 和 P4 的浓度及其受体的 mRNA 表达来描述输卵管的局部内分泌环境。牛输卵管在屠宰场收集，根据卵巢和子宫的状态估计排卵后天数。在发情周期的第 19 至 21 天、第 0 至 1 天、第 2 至 4 天和第 5 至 7 天，收集同侧和对侧的输卵管壶腹部和峡部的样本。通过三因素方差分析分析发情周期阶段和输卵管区域（壶腹部和峡部）和侧（同侧和对侧）的影响。此外，为了阐明激素受体 mRNA 表达的调节机制，通过多元线性回归检查了 E2 和 P4 对输卵管中 mRNA 表达的影响。第 19 至 21 天的输卵管内分泌环境以 E2 占主导地位为特征，表现为 E2 浓度高而 P4 浓度低、ESR1 和 PGR mRNA 表达高、ESR2、GPER1 和 PGRMC2 mRNA 表达低，而相应的第 0 至 1 天的内分泌环境则以没有激素优势为特征。第 2 至 4 天和第 5 至 7 天的环境以与第 19 至 21 天相反的趋势为特征，即输卵管激素浓度及其受体的 mRNA 表达。此外，与第 2 至 4 天和第 5 至 7 天的对侧输卵管相比，同侧输卵管的内分泌环境以 P4 为主导，E2 浓度较低，P4 浓度较高，ESR1/2、GPER1、PGR 和 PGRMC2 mRNA 的表达也不同，PGRMC1 除外。尽管输卵管中的 E2 和 P4 影响了 ESR1/2、GPER1、PGR 和 PGRMC1/2 的 mRNA 表达，但它们在区域和侧之间的影响不同。总之，输卵管的内分泌环境根据发情周期阶段以及输卵管区域和侧而变化，这可能与发情周期阶段特异性、输卵管区域特异性和侧特异性功能有关。
