Effects of water temperature on the gonadal development and expression of steroidogenic enzymes in the gonad of juvenile red seabream, Pagrus major     

B.-S. Lim  H. Kagawa  K. Gen  K. Okuzawa 《Fish physiology and biochemistry》2003,28(1-4):161-162

The effects of water temperature on the development of hermaphroditic gonads in red seabream (Pagrus major) and on mRNA expression of cytochrome P450 aromatase (P450arom) and 11β-hydroxylase were examined. High water temperature suppressed both expression of P450arom and 11β-hydroxylase and the development of oocytes in ovarian portion of hermaphroditic gonads.  相似文献   

Localization of CCK-1R in the omasum and role of CCK in the regulation of omasal contractions in sheep     

Onaga T  Sugita A  Wakaiki R  Hara I  Kagawa K  Kirisawa R  Hayashi H 《Domestic animal endocrinology》2008,35(2):231-244

The present study examined localization of cholecystokinin receptor (CCK-R) mRNA in the muscle layer of the ovine omasum and role of CCK-R type 1 (CCK-1R) in the regulation of muscle contraction of the omasum. We demonstrated that not only CCK-R type 2 (CCK-2R) mRNA but also CCK-1R mRNA is highly expressed in the muscle layer of the ovine omasum. Application of CCK-8 to muscle strips of the greater curvature of the ovine omasum at 1-100 nM induced tonic contraction in a concentration-dependent manner, and the contractile effect of CCK-8 was inhibited by both CCK-1R antagonist lorglumide (IC(50) 2.7 and 7.9 microM in the longitudinal and circular muscle, respectively) and CCK-2R antagonist PD135,158 (IC(50) 51.4 microM in the longitudinal muscle), indicating that not only CCK-2R but also CCK-1R is functionally expressed in the plasma membrane of smooth muscles in the omasum and mediates action of exogenous CCK. Contractile effect of intravenous infusion of CCK-8 (1-30 pmol/kg/min) on omasal contraction was also confirmed in the in vivo experiments using conscious sheep in the absence and presence of atropine infusion (14.4 nmol/kg/min), and showed that circulating CCK increases omasal electromyographic (EMG) activity at lower plasma concentration than that it inhibits ruminal contractions. Taking account of our previous results in the in vivo study using other CCK-1R antagonist, it is suggested that circulating CCK, even at normal range of plasma concentration, plays a physiological role as a regulator of omasal contractions in sheep and CCK-1R mediates the action of CCK.  相似文献   

Effects of long-term grafting on follicular growth in porcine ovarian cortical grafts xenoplanted to severe combined immunodeficient (SCID) mice   总被引：2，自引：0，他引：2  

Kagawa N  Sakurai Y  Miyano T  Manabe N 《The Journal of reproduction and development》2005,51(1):77-85

To establish a tool for the study of follicular growth and development, we xenotransplanted small pieces (approximately 1 mm3) of porcine ovarian cortical tissues containing only primordial follicles and small preantral follicles under the capsules of kidneys of severe combined immunodeficient (SCID) mice (8-10 weeks old). The changes in cell proliferation and cell death/apoptosis, and vascularization in xenotransplanted follicles during follicular growth and development were analyzed histochemically at 1-26 weeks after operation. Follicles in grafted ovarian tissues grew rapidly forming an antral cavity (a hallmark of tertiary follicles) at 1 week after grafting. The diameter of the follicles in transplanted tissues ranged from 0.5 to 1.5 mm, from 0.5 to 2.0 mm and from 0.5 to 3.0 mm at 1, 2 and 26 weeks after the operation, respectively. Histological observation of ovarian tissues at 26 weeks after grafting revealed that all grafts had abundant capillary vessels, which invaded from murine organs and surrounded the growing follicles. Grafted small preantral follicles developed to the antral stages at 1 week after grafting and growing antral follicles survived at 26 weeks after grafting. The oocytes in the growing follicles were easily recovered for evaluating the quality. Our simple xenografting system is easy to use and a good experimental tool for the study of folliclular growth and development in porcine ovaries.  相似文献   

Detection of heterogeneous genotypes among Australian strains of Taylorella equigenitalis     

Matsuda M  Kagawa S  Sakamoto Y  Miyajima M  Barton M  Moore JE 《Australian veterinary journal》2000,78(1):56-57

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A survey for maternal antibodies to bovine leukemia virus (BLV) in calves born to cows infected with BLV   总被引：1，自引：0，他引：1  

K Ohshima  N Morimoto  Y Kagawa  S Numakunai  T Hirano  H Kayano 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1984,46(4):583-586

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Effects of rice feeding on growth performance and protein (amino acids) metabolism in weanling piglets     

Yusuke Tasaka  Kanako Tachihara  Ryutaro Kagawa  Ryozo Takada 《Animal Science Journal》2020,91(1)

We investigated the effects of rice feeding on growth performance and protein (amino acids) metabolism of weanling piglets. In all, 16 weanling piglets with an average initial weight of 7.5 kg were divided into two groups. One group was fed a corn‐soybean meal‐based diet, and the other was fed a rice‐soybean meal diet, containing around 46% of corn or rice, respectively. A two‐week growth trial was conducted. The average daily gain (p = .025) and feed efficiency (p = .011) in rice‐fed piglets were significantly higher than those in corn‐fed piglets. Liver lysine‐ketoglutarate reductase activity tended to be lower (p = .073) in rice‐fed piglets than in corn‐fed piglets. Plasma urea nitrogen concentration in rice‐fed piglets was significantly lower than that in corn‐fed piglets. Plasma glucose and insulin concentrations were significantly higher in rice‐fed piglets than in corn‐fed piglets. Plasma‐free valine, isoleucine, and tryptophan concentrations were significantly higher in rice‐fed piglets than in corn‐fed piglets. In contrast, plasma histidine concentration was significantly lower in rice‐fed piglets than in corn‐fed piglets. Overall, these results show that rice feeding improves the growth performance and affects the protein (amino acids) metabolism in weanling piglets.  相似文献   

Arabidopsis NPL1: a phototropin homolog controlling the chloroplast high-light avoidance response     

Kagawa T  Sakai T  Suetsugu N  Oikawa K  Ishiguro S  Kato T  Tabata S  Okada K  Wada M 《Science (New York, N.Y.)》2001,291(5511):2138-2141

Chloroplasts relocate their positions in a cell in response to the intensity of incident light, moving to the side wall of the cell to avoid strong light, but gathering at the front face under weak light to maximize light interception. Here, Arabidopsis thaliana mutants defective in the avoidance response were isolated, and the mutated gene was identified as NPL1 (NPH-like 1), a homolog of NPH1 (nonphototropic hypocotyl 1), a blue light receptor used in phototropism. Hence, NPL1 is likely a blue light receptor regulating the avoidance response under strong light.  相似文献   

Effects of gonadotropin-releasing hormone agonist and testosterone on gonadotropin subunit gene expression in female red seabream (Pagrus major)     

N. Kumakura  K. Okuzawa  S. Yamaguchi  K. Gen  B.S. Lim  H. Kagawa 《Fish physiology and biochemistry》2003,28(1-4):99-100

We examined the effects of gonadotropin-releasing hormone agonist (GnRHa) and testosterone (T) on the level of gonadotropin subunit mRNAs in the pituitary of ovariectomized or intact female red seabream. Ovariectomy induced increase of seabream (sb) GnRH, glycoprotein (GP) α and luteinizing hormone (LH) β mRNA levels. GnRHa treatment also stimulated GPα and LHβ mRNA levels. T treatment reduced GPα and LHβ mRNA expression probably via negative feedback action on sbGnRH. Both GnRHa and T treatment had no effect on follicle-stimulating hormone (FSH) β mRNA levels. These results suggest that the regulatory mechanisms of GPα and LHβ gene expression differ from those of FSHβ gene.  相似文献   

Effect of high water temperature on brain-pituitary-gonad axis of the red seabream during its spawning season     

Koichi Okuzawa  Naoki Kumakura  Koichiro Gen  Sonoko Yamaguchi  Bong-Soo Lim  Hirohiko Kagawa 《Fish physiology and biochemistry》2003,28(1-4):439-440

In the present study, we examined the effect of high water temperature on brain-pituitary-gonad (B-P-G) axis of a perciform fish red seabream, Pagrus (Chrysophrys) major during its spawning season (April-May). High water temperature negatively affected all levels in B-P-G axis and turned out to be the termination factor of the spawning season of this species.  相似文献   

Seabream GnRH: partial cDNA cloning, localization and stage-dependent expression in the ovary of snake head murrel, Channa striatus     

I. Swapna  G. Sreenivasulu  M. K. Rasheeda  K. Thangaraj  R. Kirubagaran  K. Okuzawa  H. Kagawa  B. Senthilkumaran 《Fish physiology and biochemistry》2005,31(2-3):157-161

Vertebrate reproduction is under the neuroendocrine control of the hypothalamic decapeptide GnRH which synchronizes various reproductive events and influences other reproduction related aspects like spawning behavior and pheromonal action in fish. Multiple forms of GnRH peptides have been reported across diverse vertebrate and invertebrate classes. Here we report the partial seabream GnRH (sbGnRH) cDNA sequence cloned from the brain of Channa striatus (snake head murrel) a fresh water perciform with immense economic and medicinal value across Asiatic countries. sbGnRH mRNA was found in brain, gill and ovary of mature murrel with possible implications to the effect of GnRH on pheromonal phenomena and on reinitiation of oocyte meiosis. In keeping with the earlier reported role of GnRH in initiation of oocyte meiosis we here present evidence from RT-PCR, ICC demonstrating an increase in the level of sbGnRH mRNA in ovary from pre-vitellogenic to post-vitellogenic follicles.  相似文献