Possible roles of local oviductal estradiol-17β in luteal formation phase on the function of bovine oviductal epithelium

Abstract

Oviducts play an important role in the reproductive process, such as in gamete transport, fertilization, and early embryonic development. However, the regulation of oviductal function during 4−5 days post-ovulation (luteal formation phase), which is a crucial phase for early embryonic development, remains poorly understood. This study investigated the roles of oviductal estradiol-17 (E2) and progesterone (P4) concentrations on bovine oviductal functions during the luteal formation phase using RT-qPCR for some genes of oviductal epithelial cells. Bovine oviducts ipsilateral to the corpus luteum (CL) in the luteal formation phase were collected from a slaughterhouse. The concentration of oviductal E2 was positively correlated with the mRNA expressions of nuclear P4 receptor (PGR) and protein disulfide isomerase family A member 4 (PDIA4), which is related to protein secretion, in the ampulla and with estrogen receptor α (ESR1) mRNA expression in the isthmus. In contrast, the concentration of oviductal P4 was not correlated with oviductal mRNA expressions in either regions. Furthermore, for the candidate factor related to the oviductal E2 concentration, the CL parameters (CL size and tissue P4 concentration), first-wave dominant follicle (W1DF) parameters (follicle size and intrafollicular E2 concentration), and W1DF location (ipsilateral or contralateral to CL) did not influence the oviductal E2 concentration. In conclusion, our results suggest that the local oviductal E2 is a potential oviductal function regulator during the luteal formation phase.

A comparative transcriptome and proteomics study of post‐partum ovarian cycle arrest in yaks (Bos grunniens)

“…Dominant follicles experience a reduction in FSH dependence, but acquire increased LH dependence as they grow during the low FSH levels of follicular waves (Mihm et al., 2006; Ziecik et al., 2005). The oestradiol receptor ( ER ) mRNA is greater in the pituitary gland tissue than in other glands during oestrus of yak (Huo et al., 2015), and this oestradiol (E 2 ) peak is smaller than that of the follicular phase (Hazano et al., 2019; Rantala et al., 2014).…”

A Comparative Transcriptome and Proteomics Study of Postpartum Ovarian Cycle Arrest in Yaks

“…Dominant follicles experience a reduction in FSH dependence, but acquire increased LH dependence as they grow during the low FSH levels of follicular waves [15,16]. The estradiol receptor (ER) mRNA is greater in the pituitary gland tissue than in other glands during estrus of yaks [17] and this estradiol (E 2 ) peak is smaller than that of the follicular phase [18,19].…”