Reproductive Physiology

Staff

Prof. Dr. KIMURA Koji
E-mail：kimurak(please add @okayama-u.ac.jp)
Specialty:Reproductive Physiology
Establishment of pregnancy in farm animals

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Research Topics

Reproduction is regulated by many hormones in mammals. Our research is focused on understanding the complex mechanisms regulating the functions of the ovary, endometrium and oviduct in cows and horses. We have a good command of in vitro techniques which allow us to study the regulation of the functions of individual genes involved in the regulation of the reproductive function. The objectives of our research are to enhance the reproductive efficiency of food-producing animals.

Study on the local regulating mechanisms of luteal functions

Corpus luteum: The corpus luteum (CL) is a structure on the ovary which secretes progesterone, a hormone required for normal pregnancy in all mammals. If pregnancy is not established, the CL regresses and disappears from the ovary.
　a) Regulatory mechanisms of progesterone production throughout the luteal phase
　b) Apoptotic and anti-apoptotic mechanism of luteal cells
　c) Effects of cytokines derived from immune cells which migrate into CL before luteolysis.

Study on the local regulating mechanisms of endometrial function

Endometrium: The mammalian endometrium changes morphologically and functionally throughout the estrous cycle. Prostaglandins (PGs), which relate to establish pregnancy, maternal recognition of pregnancy and implantation and CL regression, are produced by endometrium.
　a) Regulatory mechanisms of PGF2α (a hormone which induces luteolysis) production
　b) Secretory mechanisms of PGE2 (a hormone for establishment of pregnancy)
　c) Mechanism of periodic proliferation and degeneration of bovine endometrium
　d) Relationship between the uterine function and the establishment of pregnancy in cattle.

Study on the regulating mechanisms of transport of gametes and embryo in oviduct

Oviduct: Oviduct provides the optimal environment for fertilization, early embryonic development and transport of gametes and embryo. Oviductal smooth muscle motility and ciliary beating of epithelial cells are important for the transport of gametes and embryo.
　a) Regulatory mechanism of transport of gametes and embryo by oviductal smooth muscle contraction and relaxation and ciliary beating of epithelial cell
　b) Mechanism of environmental control for fertilization and early embryonic development in the oviduct

Publication List

Sakai S, Yagi M, Fujime N, Kuse M, Sakumoto R, Yamamoto Y, Okuda K, Kimura K. Heat stress influences the attenuation of prostaglandin synthesis by interferon tau in bovine endometrial cells. Theriogenology, 165:52-58. (2021)
Sakai S, Hatabu T, Yamamoto Y, Kimura K. Alteration of chemokine production in bovine endometrial epithelial and stromal cells under heat stress conditions. Physiol Rep, 8:e14640. doi: 10.14814/phy2.14640. (2020)
Ito S, Yamamoto Y, Kimura K. Analysis of ciliogenesis process in the bovine oviduct based on immunohistochemical classification. Mol Biol Rep, Feb;47(2):1003-1012. doi: 10.1007/s11033-019-05192-w. (2020)
Yamamoto Y, Ito S, Okuda K, Kimura K. Involvement of activin signal pathway in cyclic apoptosis of the oviductal isthmic epithelium in cows. Theriogenology, 153:143-150. (2020)
Yamaguchi T, Maeda M, Ogata K, Abe J, Utsumi T, Kimura K. The effects on the endocrine system under hepatotoxicity induction by phenobarbital and di(2-ethylhexyl)phthalate in intact juvenile male rats. J Toxicol Sci. Jul;44(7): 459-469. (2019)
Sakai S, Hagihara N, Kuse M, Kimura K, Okuda K. Heat stress affects prostaglandin synthesis in bovine endometrial cells. J Reprod Dev, Aug 20;64(4):311-317. doi: 10.1262/jrd.2018-051. (2018)
Nishie T, Kobayashi Y, Kimura K, Okuda K.: Acute stimulation of a smooth muscle constrictor by oestradiol-17β via GPER1 in bovine oviducts. Reprod Domest Anim Apr;53(2):326-332.(2018)
Yoshimoto Y, Nishie T, Ito S, Kobayashi Y, Yamamoto Y, Okuda K, Kimura K: Adrenomedullin regulates the speed of oviductal fluid flow in cattle. Mol Reprod Dev,84 (8):712-718. doi: 10.1002/mrd.22852 (2017)
Fadhillah, Yoshioka S, Nishimura R, Yamamoto Y, Kimura K, Okuda K: Hypoxia-inducible factor 1 mediates hypoxia-enhanced synthesis of progesterone during luteinization of granulosa cells. J Reprod Dev, Feb;63(1):75-85. doi: 10.1262/jrd.2016-068 (2017)
Horihata K, Yoshioka S, Sano M, Yamamoto Y, Kimura K, Skarzynski DJ, Okuda K: Expressions of lipoprotein receptors and cholesterol efflux regulatory proteins during luteolysis in bovine corpus luteum. Reprod Fertil Dev, Jul;29(7):1280-1286. doi: 10.1071/RD15538. (2017)

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