@article{oai:rakuno.repo.nii.ac.jp:00006103,
 author = {SUGIURA, Tomochika and 杉浦, 智親 and AKIYOSHI, Shun and INOUE, Fumihiro and YANAGAWA, Yojiro and MORIYOSHI, Masaharu and 田島, 誉士 and KATAGIRI, Seiji},
 issue = {2},
 journal = {Journal of Reproduction and Development},
 month = {},
 note = {Article, The objective of this study was to investigate cyclical changes in endometrial thickness in relation to progesterone (P_4) and estradiol-17β (E_2) concentrations during natural and induced estrus in 15 cows. In the prostaglandin (PG) |<F2α>-induced estrus group, ultrasonography (USG) at 6-h intervals was used to determine endometrial thickness 48–24 h before the PGF_<2α> treatment until 24 h after ovulation (ovulation = Day 0). In the natural estrus group, USG was performed every 48 h from Day 3 to Days 15–18 after the first ovulation, and then every 6 h until 24 h after ovulation. Endometrial thickness was standardized using Day 13 as a reference day. Blood was collected during every USG examination and plasma P_4 and E_2 concentrations were determined. Endometrial thickness of the induced estrus group (n = 11) was greater than that of the natural estrus group (n = 9) between 60 and 12 h before ovulation (P < 0.05). In the natural estrus group, prior to an increase in endometrial thickness, a decrease in P_4 and an increase in E_2 were detected. In the induced estrus group, based on the time of ovulation, an increase in endometrial thickness was detected at the same time of a decrease in P_4 before an increase in E_2. These results suggest that decreases in P_4 concentrations may be a cue to changes in endometrial thickness, while increases in E_2 concentrations appear to sustain and/or enhance these changes.},
 pages = {135--143},
 title = {Relationship between bovine endometrial thickness and plasma progesterone and estradiol concentrations in natural and induced estrus},
 volume = {64},
 year = {2018}
}