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1.
The main objective of the present study is to investigate the molecular mechanism underlying the delay in progression of nuclear maturation in oocytes derived from cows with damaged livers (DL cows), which was previously reported. In present study, delayed progression of nuclear maturation of oocytes derived from DL cows relative to oocytes derived from cows with healthy livers (HL cows) was accompanied by low maturation promoting factor (MPF) activity (0.43 fold, p < 0.05). When cumulus cells were removed from cumulus‐oocyte complexes and the denuded oocytes were cultured, there was no difference in the progression of nuclear maturation between the two liver conditions. In addition, gap junctional communication (GJC) between the oocyte and cumulus cells was higher in DL cows than in HL cows at 3 and 7 h of in vitro maturation (IVM) (p < 0.05). Supplementation of IVM medium with epidermal growth factor (EGF) increased the ratio of germinal vesicle breakdown (GVBD) of oocytes derived from DL cows to the level seen in oocytes derived from HL cows. Additionally, the level of p38MAPK phosphorylation at 0 h of IVM was significantly lower in cumulus cells derived from DL cows than in cumulus cells derived from HL cows (HL cows, 53.5%; DL cows, 28.9%; p < 0.05). Thus, a low level of p38MAPK phosphorylation in cumulus cells induced slow GJC closure between oocyte and cumulus cells, which resulted in slow meiotic maturation of oocytes derived from DL cows. 相似文献
2.
Periodic signaling controlled by an oscillatory circuit that includes protein kinases ERK2 and PKA 总被引：1，自引：0，他引：1
Maeda M Lu S Shaulsky G Miyazaki Y Kuwayama H Tanaka Y Kuspa A Loomis WF 《Science (New York, N.Y.)》2004,304(5672):875-878
Self-regulating systems often use robust oscillatory circuits. One such system controls the chemotactic signaling mechanism of Dictyostelium, where pulses of adenosine 3',5'-monophosphate (cAMP) are generated with a periodicity of 7 minutes. We have observed spontaneous oscillations in activation of the mitogen-activated protein (MAP) kinase ERK2 that occur in phase with peaks of cAMP, and we show that ERK2 modulates cAMP levels through the phosphodiesterase RegA. Computer modeling and simulations of the underlying circuit faithfully account for the ability of the cells to spontaneously generate periodic pulses during specific stages of development. Similar oscillatory processes may occur in cells of many different species. 相似文献
3.
Effects of dietary protein and growth hormone-releasing peptide (GHRP-2) on plasma IGF-1 and IGFBPs in Holstein steers 总被引：1，自引：0，他引：1
This study was conduct to determine the influence of dietary protein on the response of plasma insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding proteins (IGFBPs) to exogenous growth hormone releasing peptide-2 (GHRP-2 or KP 102) in Holstein steers. Eight 16-month-old Holstein steers were grouped by liveweight to two feeding treatments; high protein (HP; CP 1.38 kg/day and TDN 4.5 kg/day DM intake, n=4) or low protein (LP; CP 0.66 kg/day and TDN 4.42 kg/day DM intake, n=4). The experiment was a single reverse design whereby each group was injected twice daily with GHRP-2 (12.5 microg/kg body weight (BW)/day) or saline solution into the jugular vein for a 6-day period. Plasma IGF-1 in the HP group were higher than in the LP group (P<0.05), but plasma 34 kDa IGFBP-2 was lower in the HP than the LP group (P<0.05). The amplitude of the maximum growth hormone (GH) peaks responding to GHRP-2 injection were higher at day 1 than at day 6 of saline or GHRP-2 treatment in both LP and HP steers (P<0.05). The area under the GH response curve for 180 min after the GHRP-2 injection was not significantly different between the LP and the HP groups at days 1 and 6. A response in plasma IGF-1 concentration to GHRP-2 treatment in the HP group was observed at day 1 (198.9+/-18.1 ng/ml), day 2 (195.2+/-21.1 ng/ml) and day 6 (201.3+/-14.8 ng/ml) (P<0.05). No increase in plasma IGF-1 was observed from GHRP-2 administration in the LP group. Although the response of plasma IGF-1 concentration to GHRP-2 administration was increased in the HP group (P<0.05), there was no apparent effect of GHRP-2 treatment on plasma 38-43 kDa IGFBP-3 and 34 kDa IGFBP-2 at days 2 and 6 of treatment. In conclusion, it is proposed that the 34 kDa IGFBP-2 is sensitive to dietary protein level and may play an important role in the regulation of circulating IGF-1 in ruminant. In addition, increased plasma IGF-1 concentration observed in the HP group in response to the GHRP-2 treatment did not appear to affect plasma IGFBPs. 相似文献
4.
Kagawa N Kuwayama M Miyano T Manabe N 《The Journal of reproduction and development》2005,51(6):741-748
This is the first report to show morphological evidence of in vitro maturation of oocytes recovered from xenotransplanted antral follicles. To develop a suitable tool for studing the growth and maturation of follicles and oocytes, we xenotransplanted small pieces of ovarian cortical tissue from sows, which contained small preantral follicles (primordial, primary, and secondary follicles; less than 0.05, 0.1 and 0.3 mm in diameter, respectively), under the capsules of kidneys of adult female severe combined immunodeficient (SCID) mice for 2 and 8 weeks, and then recovered cumulus-oocyte complexes from the growing tertiary follicles in xenografted tissues. The distribution of processes from cumulus cells to oocytes and the follicular growth, development, and maturation during xenotransplantation were histochemically analyzed. Tertiary follicles, 0.5 to 3.0 mm in diameter, were obtained from grafted tissues 2 (85%: 52 follicles/61 grafted tissues) and 8 (50%: 15/30) weeks after xenotransplantation, and then oocytes, which were tightly attached to cumulus cells, were collected from each tertiary follicle and cultured to assess their quality. At 2 weeks after grafting, 17.6% of the oocytes had matured to the metaphase II stage, but no such maturation was observed 8 weeks after grafting. Thus, in the 2 weeks group, preantral follicles rapidly grew in xenotransplanted porcine ovarian tissues to the tertiary stage, and oocytes could be recovered and matured from them by in vitro culture. 相似文献
5.
Ushijima H Yoshioka H Esaki R Takahashi K Kuwayama M Nakane T Nagashima H 《The Journal of reproduction and development》2004,50(4):481-486
An efficient cryopreservation protocol for porcine morulae was investigated with three types of vitrification having different cooling rates (Exp. 1). Survival of embryos vitrified after removal of cytoplasmic lipid droplets was also examined by means of the minimum volume cooling (MVC) method (Exp. 2). In Exp. 1, the morula stage embryos were vitrified with a 0.25 ml plastic straw (ST-method), gel loading tip (GLT-method) and the MVC-method, respectively, and stored in liquid nitrogen after which they were warmed in sucrose solutions with cryoprotectants being subsequently removed in a stepwise manner. In Exp. 2, morulae were centrifuged with 7.5 microg/ml cytocharasin B at 12000 x g for 20 min to polarize the cytoplasmic lipid droplets that were then removed from the embryos by micromanipulation (delipation). Both those delipated at the morula stage and the intact embryos at the morula to blastocyst stages were vitrified by the MVC-method. In vitro survival of the vitrified embryos was assessed in both experiments by culturing in NCSU-23 + 10% FCS for 48 h. In vitro developments of vitrified embryos after warming to blastocysts were 20% (6/30) for the ST-method, 39% (18/46) for the GLT-method, and 60% (26/43) for the MVC-method. Embryo survival was further improved by vitrification after delipation (95%, 35/37) compared to intact vitrified morulae (24/42, 57%, P<0.001) and blastocysts (23/31, 74%, P<0.05). Moreover, the number of cells in blastocysts (92 +/- 25) derived from the delipated-vitrified morulae was comparable to those derived from intact control non-vitrified embryos (103 +/- 31). Our results demonstrate that vitrified porcine morulae have the highest survival when using the MVC-method in conjunction with delipation. 相似文献
6.
Sakamoto A Iwata H Sato H Hayashi T Kuwayama T Monji Y 《The Journal of reproduction and development》2006,52(5):669-674
Oocytes lose their developmental competence during prolonged storage of the ovary. In the present study, we supplemented the preservation solution for pig ovaries (phosphate buffered saline, PBS) with glucose and preserved the ovaries for 6 h at 25 C. Subsequently, we examined the glucose concentration of the follicular fluid (FF), pH of the FF, survival rate of the granulosa cells, and maturation and developmental competence of oocytes after storage. During storage, the glucose concentration of the FF (2.1 mM), pH of the FF (7.4), and survival rate of the granulosa cells (69.5%) rapidly decreased (glucose concentration: under 1.1 mM; pH: 6.8; and survival rate: 43%). On the other hand, when the preservation solution was supplemented with glucose (15 mM), the glucose concentration of the FF increased and the survival rate of the granulosa cells improved, although the pH of the FF decreased further (from 6.8 to 6.6). In addition, supplementation with glucose significantly improved the rates of oocytes at metaphase II (0 h: 65.0%; 6 h without glucose: 23.8%; and 6 h with glucose: 43.8%) and attenuated the decline in the rates of fertilization and development that resulted from prolonged storage, although there were no significant differences. In conclusion, modification of the preservation solution by the addition of glucose increased the glucose concentration of the FF and improved the rate of maturation of pig oocytes. 相似文献
7.
Kuge T Iwata H Kuwayama T Domeki I Shioya Y Monji Y 《The Journal of reproduction and development》2006,52(3):391-396
Estrus induction is an important step in embryo production. It has been difficult to induce estrus in miniature pigs by intramascular (i.m.) injection of prostaglandin F2alpha (PGF2(2alpha)) in the early luteal stage of the estrous cycle. In the present study, we injected two different doses of PGF2(2alpha) i.m. and into the submucosa of the vaginal vestibule (i.ves.) of miniature pigs, and examined the effect of these treatments on estrus induction. Fifteen miniature pigs were divided into five experimental groups (control, saline injected i.m.; PGF2alpha treated, 1.0 or 1.5 mg of PGF2alpha injected twice i.m. or i.ves.), and the estrus length and concentrations of 17beta-estradiol (E2) and progesterone (P) in the blood were examined. Estrus length was significantly shortened by a large amount of PGF2alpha injected i.ves. In addition, the concentration of P in the blood significantly decreased after two injections of PGF2alpha (i.m. or i.ves.). These results suggest that in miniature pigs, administration of at least 3.0 mg of PGF2alpha is required for the induction of luteolysis and injection of PGF2alpha into the vaginal vestibule is a useful method of estrus induction. 相似文献
8.
H Iwata H Tanaka T Kanke Y Sakaguchi K Shibano T Kuwayama Y Monji 《Reproduction in domestic animals》2010,45(5):888-895
Follicle growth, oocyte quality or oocyte growing environment (follicular fluid) were evaluated in cows with severe liver damage (haemorrhage, telangiectasis, cholangitis and abscess) that were visually diagnosed at the slaughterhouse. Holstein cows aged 40–90 months with either a healthy liver (HL cow) or damaged liver (DL cow) were selected as donors. Follicle development kinetics was evaluated by counting the follicles at various developmental stages. In addition, the biochemical characteristics of the follicular fluids, developmental competence of preantral follicles cultured for 16 days in vitro and the ability of oocytes to develop to the blastocyst stage 8 days after fertilization were examined. DL cows had fewer secondary follicles than HL cows, and the correlation between the number of secondary follicles and the number of primary follicles differed among DL and HL cows. The follicular fluid of DL cows contained significantly lower levels of albumin and a higher total protein content than that of HL cows. Oocyte nuclear maturation assessed at 5, 16 and 21 h after beginning of culture was slower in DL cows than in HL cows, although the final maturation rates did not differ. The rate of polyspermic fertilization was significantly higher and the proportion of cleavage at 48 h after insemination and blastulation lower in DL cows compared with HL cows. When preantral follicles were cultured in vitro, the rate of follicles with normal morphology was lower in DL cows than in HL cows. These findings suggest that the kinetics of folliculogenesis differ among DL and HL cows and the developmental ability of preantral follicles and oocytes is lower in DL cows than in HL cows. 相似文献
9.
Hiroshi Tajimi Tsugumi Yamazaki Syoko Oike Tatsuyuki Yoshida Konosuke Okada Masashige Kuwayama Hitoshi Ushijima 《Animal Science Journal》2018,89(8):1194-1200
This study was conducted to examine the utility of vitrification for bovine embryos with low‐quality grade, and simple cryoprotectants dilution method for practitioners. In Experiment 1, survival of frozen embryos was compared with that of vitrified embryos using minimum volume cooling (MVC). Then, vitrified embryos were used to confirm the optimum sucrose concentration in Experiment 2. The survival rates of embryos that had been vitrified following diluted cryoprotectants with the one‐step in‐straw method were compared with those of fresh control embryos in Experiment 3. Frozen‐thawed or vitrified‐warmed blastocysts were cultured with TCM‐199 supplemented with 100 μmol/L beta‐mercaptoethanol +5% fetal bovine serum at 38.5°C in an atmosphere of 5% CO2 in air, their survival after 24 hr were compared. The development to term of fair quality in vivo embryos after vitrification was examined in Experiment 4. Results show that survival rates of frozen‐thawed embryos were lower (p < .05) than that of vitrified‐warmed ones. When vitrified embryos were warmed in 0.3 mol/L sucrose in straws, their survival rate was 100%. The total cell numbers of vitrified‐warmed embryos were comparable to those of fresh control embryos. The six calves from 13 vitrified embryos were delivered in Experiment 4. These results indicate that MVC vitrification following one‐step cryoprotectants dilution is utilized to preserve low‐quality bovine embryos. 相似文献
10.
ThanThan S Saito T Yannaing S Zhao H Nakashima K Kuwayama H 《Domestic animal endocrinology》2012,42(3):155-164
Oxyntomodulin (OXM), glucagon, and glucagon-like peptide-1 (GLP-1), peptide hormones derived from the glucagon gene, play an important role in glucose homeostasis. The insulinotropic action of these three homologous peptides has been well documented in monogastric animals. However, information on the relationships among these peptides in insulin-releasing action, specifically in ruminants, is still insufficient. In this regard, we carried out two experiments in cattle. In experiment 1, effects of glucagon and GLP-1 on plasma insulin and glucose were investigated in 10-mo-old Holstein steers (347 ± 8 kg, n = 8) under normoglycemic conditions. Peptides were administered intravenously at dose rates of 0.12, 0.25, 0.50, and 1.25 nmol/kg body weight (BW). In experiment 2, the relationships among OXM, glucagon, and GLP-1 in the insulinotropic and glucoregulatory actions were elucidated in 3-mo-old Holstein steers (94 ± 2 kg, n = 8) using agonist-antagonist strategy. In agonist strategy, these three peptides were administered alone or coadministered at dose rates of 10 μg of OXM/kg BW, 4 μg of glucagon/kg BW, and 2 μg of GLP-1/kg BW. In antagonist strategy, 2 μg of each peptide was administered alone or in combination with 10 μg of [des His1, des Phe6, Glu9] glucagon amide (a glucagon receptor antagonist) or exendin-4 (5-39) amide (a GLP-1 receptor antagonist). Our results showed that OXM, glucagon, and GLP-1 had insulinotropic actions in ruminants under normoglycemic conditions. Our results also showed that the insulin-releasing effects of OXM and glucagon were mediated through both GLP-1 receptors (GLP-1R) and glucagon receptors. These insulinotropic effects of OXM and glucagon through GLP-1R were inhibited by GLP-1. Our findings expand the relationships among OXM, glucagon, and GLP-1 in the insulinotropic and glucoregulatory actions. 相似文献