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| Registros recuperados: 77 | |
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| Fukui, Yutaka; Yamamura, Kunio; Matsunaga, Nobuyoshi; Miyamoto, Akio; 福井, 豊; 宮本, 明夫. |
| The present study aimed to examine the possibility that bovine somatotropin (BST) treatment after artificial insemination (AI) may improve the fertility by the stimulation of corpus luteum (CL) function in seasonally anestrous ewes. The experiment was conducted at the Tawa Field Station, Shibecha-cho in Hokkaido, Japan, during the non-breeding season (May, 1995). Eighty-nine mature (2 to 3 years old) Suffolk and Suffolk-crossed ewes were treated with controlled internal drug release devices containing 0.3 g progesterone (CIDR-G) for 12 days. Ewes were injected intramuscularly with 500 IU PMSG the day before CIDR removal. Eighty-seven ewes were assigned to an insemination of frozen semen on a fixed-time basis (42 to 50 h) after removal of CIDR. On the 11th... |
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Palavras-chave: Bovine somatotropin; Artificial insemination; Progesterone; Conception rate; Ewes. |
| Ano: 2000 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2971 |
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| Ozawa, Takahiro; Acosta, Tomas J.; Nakamura, Tadashi; Miyamoto, Akio; 中村, 正; 宮本, 明夫. |
| The presence of gonadotropin-releasing hormone (GnRH)-like protein has been previously demonstrated in the bovine follicle. This GnRH-like protein was purified and concluded to be histone H2A. However, neither GnRH peptide nor specific GnRH-immunoreactivity (GnRH-IR) has been demonstrated in the bovine follicle so far. Thus, this study focused on the detection of specific GnRH-IR using the second-antibody enzyme immunoassay in isolated bovine mature follicles, and on an examination of the direct effect of luteinizing hormone (LH), endothelin-1 (ET-1), and cytokines on the GnRH-IR using an in vitro microdialysis system (MDS). We further examined a cross-reactivity of the GnRH antibody with bovine histone H2A. GnRH-IR was detected in microdialyzed perfusate... |
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Palavras-chave: GnRH; Immunoreactivity; Microdialysis; Follicle; Cow. |
| Ano: 2000 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2970 |
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| KOBAYASHI, Shu-ichi; MIYAMOTO, Akio; 宮本, 明夫. |
| Luteal cells utilize lipoproteins (LIPs) for progesterone (P) synthesis. A luteolysin prostaglandin F2α (PGF 2α) has shown to prevent the LIPs utilization for steroidogenesis in bovine midcycle luteal cells. However, a luteolytic injection of PGF2α before Day 5 (Day 0=estrus) can not induce the regression of the corpus luteum (CL). This suggests that the intraluteal mechanism of PGF2 α action on the LIPs utilization in early CL is different from that of the mid luteal stage. Thus, this study aimed to investigate the interaction between PGF2 α and LIPs on the secretion of P and oxytocin (OT) from bovine early CL. An in vitro microdialysis system (MDS) was used as a model. Each bovine early CL (Days 3-4) was implanted with the MDS, and maintained in an organ... |
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Palavras-chave: PGF2α; Lipoproteins; Early CL; Cow. |
| Ano: 2000 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2972 |
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| OHTANI, Masayuki; OKI, Naoko; TANIMURA, Miyune; KOBAYASHI, Shu-ichi; ACOSTA, Tomas J.; HAYASHI, Kanako; MIYAMOTO, Akio; 宮本, 明夫. |
| It is well known that an injection of prostaglandin F2α (PGF2α) or its analogue during the mid luteal phase of the estrous cycle induces a rapid decrease in plasma progesterone (P4) concentration, followed by luteolysis in the cow. There is evidence that a potent vasoactive peptide, endothelin-1 (ET-1), is produced in the bovine corpus luteum (CL), and that it is directly involved in luteolysis. We previously found that ET-1 concentrations in the peripheral plasma increase during the period of luteolysis and ovulation in cows. However, it is not clear whether the elevation of peripheral plasma ET-1 concentration observed during luteolysis and ovulation originates exclusively from the ovary and/or CL. Such a profile of plasma ET-1 concentration may be... |
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Palavras-chave: Endothelin; Progesterone; Plasma; Calves; Cows. |
| Ano: 2001 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2973 |
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| KOBAYASHI, Shu-ichi; ACOSTA, Tomas J.; HAYASHI, Kanako; BERISHA, Bajram; OZAWA, Takahiro; OHTANI, Masayuki; SCHAMS, Dieter; MIYAMOTO, Akio; 宮本, 明夫. |
| It is well known that prostaglandin (PG) F2α and PGE2 are actively produced by bovine early corpus luteum (CL) at higher levels than in the CL of later stages. However, there is no in vivo information about the local secretion of PGs within bovine developing CL so far. Thus, the objective of the present study was to determine in detail the real-time changes in PGF2α and PGE2 secretion within developing CL. A microdialysis system (MDS) was surgically implanted into the newly formed CL of 6 cows on Day 3 after GnRH administration (about 1.5 days after ovulation) to induce superovulation following FSH treatment. Both PGF2α and PGE2 release were high during the first 24 h within developing CL but decreased thereafter. These profiles were well reflected in the... |
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Palavras-chave: PGF2α; PGE2; Developing CL; Cow; In vivo. |
| Ano: 2002 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2974 |
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| HAYASHI, Ken-Go; BERISHA, Bajram; MATSUI, Motozumi; SCHAMS, Dieter; MIYAMOTO, Akio; 松井, 基純; 宮本, 明夫. |
| Recent findings indicate that the changing profile of angiopoietins (ANPT) and their receptor Tie2 are closely associated with development and regression of the vascular network in the cyclic ovary. We previously reported that mRNA expression for the ANPT-Tie system in theca interna changes during bovine follicular development and atresia, and both ANPTs affect steroidogenesis in the preovulatory follicle. The aim of this study was to investigate mRNA expression for ANPT1, ANPT-2 and Tie2 in granulosa cells (GC) during follicular development in the cow. Bovine follicles were classified according to the estradiol-17β (E2) concentration in follicular fluid (FF) as follows: (1) E2<0.5, (2) 0.5<E2<5, (3) 5<E2<20, (4) 20<E2<180 and (5)... |
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Palavras-chave: Follicular development; Angiopoietin-Tie system; Granulosa cell; Cow. |
| Ano: 2004 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2975 |
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| Nozaki, Hirofumi; Miyamoto, Akio; Hayashi, Ken-Go; Matsui, Motozumi; Yoshida, Takashi; Nakamura, Tadashi; Arai, Ikichi; Urashima, Tadasu; 宮本, 明夫; 松井, 基純; 中村, 正; 浦島, 匡. |
| The activity of α3-D-mannoside-β-1,2-N-acetylglucosaminyltransferase I (GnT I; EC 2.4.1.101), which catalyzes the first step in the conversion of oligomannose to complex or hybrid N-glycans of glycoproteins, was detected in bovine follicular fluid (bFF). The GnT I activity in bFF had a pH optimum of 5.8 and an absolute requirement for either Co2+, Mn2+, or Mg2+, the activity being stimulated by these cations in the above order. The apparent Km value for α1-3α1-6 mannopentaose of GnT I in bFF was 2.17 mM. The substrate specificity for the GnT I activity decreased in the following order: α1-3α1-6 mannopentaose> α1-3α1-6 mannotriose>α1-3 mannobiose. The GnT I activity in bFF from large atretic follicles was significantly higher than in that from large... |
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Palavras-chave: N-acetylglucosaminyltransferase I; Dominant follicle; Atretic follicle; Follicular fluid; Bovine. |
| Ano: 2004 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4185 |
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| TANAKA, Jun; ACOSTA, Tomas J.; BERISHA, Bajram; TETSUKA, Masa; MATSUI, Motozumi; KOBAYASHI, Shuichi; SCHAMS, Dieter; MIYAMOTO, Akio; 松井, 基純; 宮本, 明夫. |
| Local angiogenesis and angiolysis in the corpus luteum (CL) relate to the luteal function. Recent studies indicate that angiopoietins (ANPT) and their receptors Tie regulate remodeling of microvasculature. We therefore examined 1) the relative changes in the expression of mRNA for ANPT-1, ANPT-2, Tie1 and Tie2 in bovine CL by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) during the estrous cycle and prostaglandin F2α (PGF2α)-induced luteolysis, and 2) the effect of ANPT-2 on progesterone (P4) release from CL at the late stage of the estrous cycle by an in vitro microdialysis system (MDS). The CLs were classified into 4 stages (early: Day 2-5, n=7, mid: Day 8-12, n=15, late: Day 15-17, n=9, regressing: Day >18, n=19). The... |
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Palavras-chave: Angiopoietin; Angiolysis; Luteolysis; Corpus luteum; Cow. |
| Ano: 2004 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2977 |
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| NOZAKI, Hirofumi; WIJAYAGUNAWARDANE, Missaka P.B.; KODITUWAKKU, Suranga P.; YOSHIDA, Takashi; NAKAMURA, Tadashi; ARAI, Ikichi; URASHIMA, Tadasu; MIYAMOTO, Akio; 中村, 正; 浦島, 匡; 宮本, 明夫. |
| N-acetylglucosaminyltransferase I (GnT I; EC 2.4.1.101), which catalyzes the first step in the conversion of oligomannose to complex or hybrid N-glycans of glycoproteins, was found in media cultured with bovine oviduct epithelial cells (BOEC) obtained from non-pregnant cows during the follicular phase. Combined treatment with specific hormones increased GnT I release from BOEC. Luteinizing hormone (LH; 10 ng/ml) alone slightly, but together with 17β-estradiol (E2; 1 ng/ml), synergistically increased GnT I activity. Vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF) α, which have been shown to have their highest activities in the bovine oviduct during the periovulatory period, also increased in GnT I activity. This study provides the... |
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Palavras-chave: Bovine; Luteinizing hormone (LH); N-acetylglucosaminyltransferase I; Oviduct; Tumor necrosis factor (TNF) α; Vascular endothelial growth factor (VEGF). |
| Ano: 2005 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2978 |
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| ACOSTA, Tomas J.; TETSUKA, Masa; MATSUI, Motozumi; SHIMIZU, Takashi; BERISHA, Bajram; SCHAMS, Dieter; MIYAMOTO, Akio; 松井, 基純; 清水, 隆; 宮本, 明夫. |
| The aim of the present in vivo study was to monitor real-time fluctuations of cortisol (Cr) in the wall of preovulatory follicles using a microdialysis system (MDS) implanted in the theca layer as well as changes in ovarian venous plasma (OVP) and jugular venous plasma (JVP). Seven cows were superovulated using FSH and prostaglandin F2α injections. Dialysis capillary membranes were surgically implanted into the theca layer of mature follicles and connected to a microdialysis system. Fractions of the perfusates were collected from Day -1 (Day 0=LH surge) to Day 3. No difference in the concentrations of Cr between JVP and OVP was detected throughout the experiment. Circulating concentrations of Cr ranged from 20 to 35 ng/ml 8 h after surgery in ovulatory and... |
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Palavras-chave: Bovine; Cortisol; Follicle; Ovary; Ovulation. |
| Ano: 2005 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2980 |
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| Registros recuperados: 77 | |
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