Shota Tokuyama

Taisho Pharmaceutical (Japan)

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Yuko Toishi

Rakuno Gakuen University

Kazuyoshi Taya

Tokyo University of Agriculture and Technology

Keisuke Kozai

University of Kansas Medical Center

Miki Sakatani

National Agriculture and Food Research Organization

Kiyoshi Okuda

Obihiro University of Agriculture and Veterinary Medicine

Yasuo NAMBO

Obihiro University of Agriculture and Veterinary Medicine

Masashi Takahashi

Hokkaido University

Gen Watanabe

Tokyo University of Agriculture and Technology

Dariusz J. Skarżyński

Institute of Animal Reproduction and Food Research

K. Okuda

Okayama University

Cooperative Institutions

Taisho Pharmaceutical (Japan)

Okayama University

Tokyo University of Agriculture and Technology

Institute of Animal Reproduction and Food Research

Polish Academy of Sciences

Taisei (Japan)

Hokkaido University

Shimane University

Gifu University

Obihiro University of Agriculture and Veterinary Medicine

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Evaluation of the new rapid assay PATHFAST for measuring progesterone in whole blood and serum of mares

Journal of Equine Veterinary Science (2013)

Yuko Toishi N. Tsunoda Masaaki Tagami Hiromitsu HASHIMOTO Fumiki KATO

Quantitative Analysis

Muramic acid

10.1016/j.jevs.2013.10.098

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Evaluation of the PATHFAST Chemiluminescent Enzyme Immunoassay for Measuring Progesterone in Whole Blood and Serum of Mares

Journal of Equine Science (2013)

Yuko Toishi Nobuo TSUNODA Masaaki Tagami Hiromitsu HASHIMOTO Fumiki KATO

Evaluation of a new chemiluminescent enzyme immunoassay, the PATHFAST assay system (PATHFAST), for measurement of circulating progesterone in mares was performed. Five mares at the mid-luteal stage were administrated a single i.m. injection of prostaglandin F2α analog (PGF2α; cloprostenol 250 μg/ml), and then blood samples were collected from the jugular vein at 0, 15, 30 and 45 min, at one-hour intervals until 24 and at 48 hr via a catheter in the jugular vein. To monitor the physiological changes in circulating progesterone in mares after induced luteolysis, concentrations of progesterone in whole blood and serum samples were measured by PATHFAST. In addition, concentrations of progesterone in serum samples measured by PATHFAST were compared with those measured by radioimmunoassay (RIA) and enzyme immunoassay (EIA). Using PATHFAST, the serum concentrations of progesterone in mares correlated highly with those of whole blood samples (r=0.9672, n=88). The serum concentrations of progesterone as measured by PATHFAST correlated well with RIA (r=0.9654, n=88) and EIA (r=0.9323, n=112). An abrupt decline in circulating progesterone in whole blood samples was observed within 2 hr (50%), followed by a gradual decline until 48 hr later. The results for progesterone in whole blood samples correlated highly with those in serum samples, and the declining pattern paralleled that of the serum samples. These results demonstrated that PATHFAST is useful in the equine clinic as an accurate diagnostic tool for rapid assay of progesterone within 26 min, using unextracted whole blood.

Chemiluminescent immunoassay

Jugular vein

Luteolysis

Venous blood

10.1294/jes.24.47

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Identification of new flavonol O-glycosides from indigo (Polygonum tinctorium Lour) leaves and their inhibitory activity against 3-hydroxy-3-methylglutaryl-CoA reductase

Journal of Pharmaceutical and Biomedical Analysis (2015)

Hideto Kimura Shota Tokuyama Tomoe Ishihara Satoshi Ogawa Kazushige Yokota

Aglycone

10.1016/j.jpba.2015.02.005

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Citations (18)

Auto-amplification system in prostaglandin F2α production by endometrium for initiating and progressing luteolysis in mares

Journal of Equine Veterinary Science (2013)

K. Okuda Shota Tokuyama Keisuke Kozai Yuko Toishi N. Tsunoda

Luteolysis

10.1016/j.jevs.2013.10.095

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Citations (1)

Evidence for a PGF2α auto-amplification system in the endometrium in mares

Reproduction (2016)

Keisuke Kozai Shota Tokuyama Anna Szóstek‐Mioduchowska Yuko Toishi Nobuo TSUNODA

In mares, prostaglandin F2α (PGF2α) secreted from the endometrium is a major luteolysin. Some domestic animals have an auto-amplification system in which PGF2α can stimulate its own production. Here, we investigated whether this is also the case in mares. In an in vivo study, mares at the mid-luteal phase (days 6-8 of estrous cycle) were injected i.m. with cloprostenol (250 µg) and blood samples were collected at fixed intervals until 72 h after treatment. Progesterone (P4) concentrations started decreasing 45 min after the injection and continued to decrease up to 24 h (P < 0.05). In turn, 13,14-dihydro-15-keto-PGF2α (PGFM) metabolite started to increase 4h after an injection and continued to increase up to 72 h (P < 0.05). PGF receptor (PTGFR) mRNA expression in the endometrium was significantly higher in the late luteal phase than in the early and regressed luteal phases (P < 0.05). In vitro, PGF2α significantly stimulated (P < 0.05) PGF2α production by endometrial tissues and endometrial epithelial and stromal cells and significantly increased (P < 0.05) the mRNA expression of prostaglandin-endoperoxide synthase-2 (PTGS2), an enzyme involved in PGF2α synthesis in endometrial cell. These findings strongly suggest the existence of an endometrial PGF2α auto-amplification system in mares.

10.1530/rep-15-0617

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Citations (15)

SP331TP0463518, A NOVEL ORAL INHIBITOR OF HYPOXIA INDUCIBLE FACTOR PROLYL HYDROXYLASE (HIF-PH) INDUCES ERYTHROPOIETIN SECRETION DOMINANTLY DERIVED FROM LIVER IN NON-DIALYSIS AND HEMODIALYSIS PATIENTS WITH CHRONIC KIDNEY DISEASE

Nephrology Dialysis Transplantation (2018)

Shota Tokuyama Masanori Fujiwara Fumihiko Sato Toshiharu Shimazaki Hirotaka Watase

Hypoxia-Inducible Factors

Hypoxia

10.1093/ndt/gfy104.sp331

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Expression of Aldo-keto Reductase 1C23 in the Equine Corpus Luteum in Different Luteal Phases

Journal of Reproduction and Development (2014)

Keisuke Kozai Takuo Hojo Shota Tokuyama Anna Szóstek‐Mioduchowska Masashi Takahashi

Regression of the corpus luteum (CL) is characterized by a decay in progesterone (P4) production (functional luteolysis) and disappearance of luteal tissues (structural luteolysis). In mares, structural luteolysis is thought to be caused by apoptosis of luteal cells, but functional luteolysis is poorly understood. 20α-hydroxysteroid dehydrogenase (20α-HSD) catabolizes P4 into its biologically inactive form, 20α-hydroxyprogesterone (20α-OHP). In mares, aldo-keto reductase (AKR) 1C23, which is a member of the AKR superfamily, has 20α-HSD activity. To clarify whether AKR1C23 is associated with functional luteolysis in mares, we investigated the expression of AKR1C23 in the CL in different luteal phases. The luteal P4 concentration and levels of 3β-hydroxysteroid dehydrogenase (3β-HSD) mRNA were higher in the mid luteal phase than in the late and regressed luteal phases (P<0.05), but the level of 3β-HSD protein was higher in the late luteal phase than in the regressed luteal phase (P<0.05). The luteal 20α-OHP concentration and the level of AKR1C23 mRNA were higher in the late luteal phase than in the early and mid luteal phases (P<0.05), and the level of AKR1C23 protein was also highest in the late luteal phase. Taken together, these findings suggest that metabolism of P4 by AKR1C23 is one of the processes contributing to functional luteolysis in mares.

Luteolysis

Hydroxysteroid Dehydrogenases

10.1262/jrd.2013-120

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Citations (6)