Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA.
Life Sci. 2012 Oct 15;91(13-14):613-7. doi: 10.1016/j.lfs.2012.02.016. Epub 2012 Mar 3.
In the ovary, endothelins regulate a variety of ovarian functions that include but not limited to folliculogenesis, steroidogenesis, oocyte maturation, ovulation and corpus luteum (CL) function. Two cognate receptors, EDNRA and EDNRB are constitutively expressed in the ovary, and mediate the regulatory endothelin actions. However, the physiological significance of the presence of the two receptors that often elicit opposite responses upon activation by an endothelin is yet to be determined. This study was proposed to test the hypothesis that both receptors are present in the ovary to lend an endothelin a finite regulation of ovulation.
A rescued EDNRB knockout (rEDNRB-KO) mouse that is deficient of EDNRB expression in all cells but adrenergic cell lineage was used to test the impact of the loss of function of EDNRB on ovulation. The EDNRB gene deletion and its confirmation at mRNA level were assessed by molecular biology techniques, and the number and size of corpus lutea was determined by ovarian histology.
Female rEDNRB-KO mice had larger litter sizes (numbers of pups per birth) and their ovaries contained more corpora lutea than wild type littermates.
This result shows that without EDNRB excessive ovulation occurs, suggesting a role of EDNRB in having the extent of ovulation confined.
在内分泌学中，内皮素调节多种卵巢功能，包括但不限于卵泡发生、类固醇生成、卵母细胞成熟、排卵和黄体（CL）功能。两种同源受体，EDNRA 和 EDNRB，在卵巢中持续表达，并介导内皮素的调节作用。然而，这两种受体的存在的生理意义，即它们在被内皮素激活时通常会产生相反的反应，仍有待确定。本研究旨在检验以下假设：即两种受体均存在于卵巢中，以赋予内皮素对排卵的有限调节作用。
使用一种挽救性 EDNRB 敲除（rEDNRB-KO）小鼠，该小鼠在所有细胞中均缺乏 EDNRB 表达，但在肾上腺素能细胞谱系中缺乏 EDNRB 表达，以测试 EDNRB 功能丧失对排卵的影响。通过分子生物学技术评估 EDNRB 基因缺失及其在 mRNA 水平上的确认，并通过卵巢组织学确定黄体的数量和大小。
rEDNRB-KO 雌性小鼠的产仔数（每次产仔的数量）更大，其卵巢中黄体的数量多于野生型同窝仔鼠。
该结果表明，没有 EDNRB 会导致过度排卵，这表明 EDNRB 在限制排卵程度方面发挥作用。
