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1.
Administration of hormones to synchronize oestrus is a useful tool in animal breeding. However, exogenous ovarian stimulation may be detrimental to reproductive function. This study was aimed to examine whether an oestrus synchronization with PGF2α/eCG/hCG could affect luteal P4 synthesis in early pregnant gilts. Corpora lutea (CLs) were collected on days 9, 12 and 16 of pregnancy from gilts with natural (n = 16) and synchronized (n = 18) oestrus and analysed for (i) the expre‐ssion of steroidogenic acute regulatory protein (StAR), cytochrome P450 family 11 subfamily A polypeptide (CYP11A1), and 3β‐hydroxysteroid dehydrogenase (3βHSD); (ii) the concentration of P4 in the luteal tissue and blood; and (iii) the expression of luteinizing hormone receptors (LHR) and oestrogen receptors (ERα and ERβ). Additionally, the effect of LH on P4 secretion from CL slices collected from synchronized and naturally ovulated animals has been studied in vitro. PGF2α/eCG/hCG administration increased mRNA expression of StAR, CYP11A1, 3βHSD, and LHR on day 9 and CYP11A1 and LHR on day 12 of pregnancy compared with the control group (p < 0.05). CYP11A1, 3βHSD, LHR, ERα and ERβ proteins were not affected by synchronization; only StAR protein increased in hormonally treated animals (p = 0.017). The concentration of P4 in luteal tissue was greater on day 9 (p < 0.01), but lower on day 16 (p < 0.05) in gilts with hormonally induced oestrus compared with control animals. Blood serum levels of P4 were lower in synchronized than control gilts (p < 0.001). Synchronization did not affect LH‐stimulated P4 secretion from luteal slices; however, greater basal concentration of P4 in incubation medium was detected for CLs collected from synchronized than control gilts (p < 0.05). In conclusion, synchronization of oestrus with PGF2α/eCG/hCG protocol in gilts did not impair the expression of luteal P4 synthesis system, although decreased P4 concentration in the blood.  相似文献   

2.
In the present study, changes in localization of nerve growth factor (NGF) and its receptors, trkA and p75 in the ovary were investigated during the estrous cycle of the golden hamster. The effect of LH surge on changes in localization of NGF, trkA and p75 in the ovary was also investigated. NGF and its receptors trkA and p75 were localized in oocytes, granulosa cells and theca cells of various stages of follicles throughout the estrous cycle. NGF and its two receptors were also present in numerous interstitial cells and luteal cells. The number of interstitial cells staining positively for NGF and its two receptors was greater in ovaries of day 1 (day 1=day of ovulation) than the other days during the estrous cycle. Treatment with the antiserum against luteinizing hormone releasing hormone (LHRH-AS) at 1100 h on day 4 completely blocked ovulation. There were few positive reactions for NGF and its two receptors in interstitial cells 24 hr after LHRH-AS injection. The effect of LHRH-AS treatment was blocked by a single injection of 10 IU human chorionic gonadotropin. The distinct widespread distribution of NGF and its two receptors in the ovary of golden hamsters suggest that NGF may be an important growth factor for regulation of ovarian function. Furthermore, the LH surge may be an important factor for inducing production of NGF and its two receptors in interstitial cells of the cyclic golden hamster.  相似文献   

3.
In this study we measured protein concentrations of insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBPs) 2-5 in porcine corpora lutea (CLs) throughout the estrous cycle (Experiment 1), and examined the effects of IGFBP-3 and IGFBP-3 antibody (AB) on luteal progesterone (P4) secretion in vitro (Experiment 2). For Experiment 1, (CLs) and serum were collected on days (D) 4, 7, 10, 13, 15 and 16 of the estrous cycle (n = 5 animals per day). IGF-I was extracted from CLs and sera, and measured by radioimmunoassay (RIA). IGFBPs were measured in CLs by ligand blots. For Experiment 2, CLs (from Experiment 1) were enzyme dissociated and luteal cells cultured (24 h) in Medium 199 (M199) containing (0-500 ng/ml) IGFBP-3 (+/-IGF-I; 100 ng/ml), or (0-10 microg/ml) IGFBP-3 AB. P4 in media was measured by RIA. In Experiment 1, luteal IGF-I concentrations (ng/g tissue) were maximal on day 4 and gradually decreased thereafter. Serum IGF-I concentrations (ng/ml) were highest on days 4 and 7, compared with days 10-15. Peak levels of luteal IGFBP-3 were also seen on days 4 and 7 of the cycle. Luteal IGFBP-2 concentrations showed a tendency to increase on day 16 (P < 0.05 versus day 10), but no significant changes in IGFBP-4 or -5 were seen. In Experiment 2, IGFBP-3 (w IGF) inhibited the steroidogenic actions of IGF-I, but had no significant actions alone (IGFBP-3 w/o IGF). Finally, IGFBP-3 AB stimulated P4 secretion on days 4 and 7, but not on days 10-16. We conclude that IGFBP-3 inhibits IGF-I actions in the porcine CL.  相似文献   

4.
The aims of this study were to study the effects of fasting on progesterone (P4) production in the pig and to verify whether fasting influences luteal expression of PGF(2alpha) receptor (FPr) and prostaglandin secretion. Superovulated prepubertal gilts were used; half of them were fasted for 72h starting on day 2 (F2) or 9 (F9) of the induced estrous cycle, respectively, while two groups (C2 and C9) served as respective controls. Plasma P4 and PGFM concentrations were determined by RIA while FPr mRNA expression in CLs collected at the end of fasting period was measured by real-time PCR. In experiment 1, plasma P4 concentrations in fasted gilts were significantly (P<0.01) higher than in controls starting from day 3 (F2; n=6) and 10 (F9; n=6). FPr mRNA expression was similar in F2 and C2 (n=6) CLs while it was significantly (P<0.05) higher in F9 than in C9 (n=6) CLs. In experiment 2, cloprostenol administered on day 12 significantly (P<0.05) increased FPr mRNA expression in CLs from both F9 (n=6) and C9 (n=6) gilts. At the time of cloprostenol injection PGFM levels were significantly higher (P<0.05) in the fasted group and cloprostenol-induced luteolysis in fasted but not in normally fed gilts. Results from this study indicate that fasting in prepubertal gilts induced to ovulate stimulates luteal P4 and PGFM production as well as FPr mRNA expression, thus increasing luteolytic susceptibility.  相似文献   

5.
Ovarian sensitivity to exogenous gonadotropin stimulation (equine chorionic gonadotropin [eCG] and human chorionic gonadotropin [hCG]) following pre-treatment with a progestin (levonorgestrel) versus GnRH antagonist (antide) was studied in cats known to be induced versus spontaneous ovulators. Queens were assigned to one of three treatments: (1) levonorgestrel implants+eCG/hCG (n=7 cats); (2) antide injections+eCG/hCG (n=7) or (3) eCG/hCG alone (control; n=7). Hormonal metabolites were assessed in fecal samples collected daily for 60 days before and during the 37 days inhibitory pre-treatment and for more than 60 days after eCG/hCG. Fecal metabolites of estradiol and progesterone were measured by radioimmunoassay. Females that maintained baseline progesterone were considered induced ovulators, whereas cats that exhibited a luteal phase before inhibition treatment were classified as spontaneous ovulators. Based on fecal hormone profiles, levonorgestrel thoroughly inhibited ovarian activity, whereas antide synchronized follicular phases but did not induce complete ovarian down-regulation. Both treatments prevented ovulation in spontaneous ovulators, but neither caused regression of existing corpora lutea (CL). Levonorgestrel, but not antide, pre-treatment resulted in a quiescent ovary at the time of eCG injection, yet endocrine responses to eCG/hCG were not different among treatments. Interestingly, spontaneously ovulating females exhibited a prolonged estradiol response to gonadotropin stimulation compared to induced ovulators, and this prolonged estradiol surge was replicated by levonorgestrel pre-treatment. Thus, the progestin levonorgestrel effectively suppresses follicular and luteal activity in the cat, resulting in a more consistent response to gonadotropin stimulation, even in females prone to spontaneous ovulation.  相似文献   

6.
The present study was undertaken to elucidate whether an increased, but physiological, amount of progesterone (P4) supplied to the porcine corpus luteum affects luteal secretion of activin A and inhibin alpha-subunit (Inhalpha) in freely moving gilts. On day 9 of the estrous cycle (EC), both ovarian arteries and both ovarian veins of gilts (n = 5) were cannulated. Progesterone was infused into the right ovarian arteries in gilts on days 10, 11 and 12 of the EC at a rate adequate to its physiological retrograde transfer found during the middle luteal phase of the EC. The P4 infusion rate was 0.62 microg/min (day 10), 2 x 0.62 microg/min (day 11) and 3 x 0.62 microg/min (day 12). The left ovarian arteries were infused with saline (control). Blood samples were collected from both ovarian veins on days 10-12 of the EC before and after P4 or saline infusion. The mean plasma activin A level in the ovarian vein ipsilateral to the P4-infused ovary was higher (P < 0.0001) on days 10-12 of the EC than this found in the contralateral ovarian vein. The level of activin A in the ovarian vein ipsilataral to the infusion of P4 was higher on days 11 (P < 0.01) and 12 (P < 0.0001) and tended to be higher (P < 0.07) on day 10 of the EC than this in contralateral ovarian vein. The level of Inhalpha in the ovarian vein ipsilateral to the P4-infused ovary on days 10-12 of the EC was not significantly different (P > 0.05) than this found in the contralateral ovarian vein. The results of the present study indicate that a local elevation of P4 concentration in blood supplying the ovary during the middle luteal phase of the porcine EC affects ovarian secretion of activin A. The effect of P4 on the secretion of activin A suggested the existence of a short regulatory loop of a positive feedback between P4 being retrogradely transferred into the ovary and the secretion of this peptide.  相似文献   

7.
The objective of the present study was to determine the temporal relationships among luteal adenylate cyclase activity, luteal phosphodiesterase activity, luteal progesterone concentration and plasma progesterone concentration during prostaglandin F2 alpha (PGF2 alpha)-induced luteolysis in ewes. Corpora lutea (CL) were removed from cycling ewes on d 9 (d 0 = first day of estrus) at 0, 2, 4, 6, 12 and 24 h (seven to eight ewes/group) after PGF2 alpha administration (im). Jugular blood samples were collected at the time of enucleation of CL and analyzed for progesterone. Plasma and luteal progesterone concentrations were decreased (P less than .05) by 4 and 12 h after PGF2 alpha injection, respectively. Basal adenylate cyclase, luteinizing hormone (LH)-activated adenylate cyclase, guanylylimidodiphosphate [Gpp(NH)p]-activated adenylate cyclase and LH plus Gpp(NH)p-activated adenylate cyclase activities were decreased (P less than .05) by 2 h after PGF2 alpha injection. The decrease in adenylate cyclase activity paralleled the decrease in plasma progesterone concentration over time. Luteinizing hormone stimulated (P less than .05) adenylate cyclase activity relative to basal activity at 0, 2, 12 and 24 h post-PGF2 alpha; whereas, Gpp(NH)p stimulated (P less than .01) adenylate cyclase activity relative to basal activity at each time point. In contrast to the decrease in adenylate cyclase activity, phosphodiesterase activity was increased (P less than .05) at 2 and 4 h post-PGF2 alpha. These results suggest that a decrease in adenylate cyclase activity coupled with an increase in phosphodiesterase activity may decrease the intracellular adenosine 3',5' cyclic monophosphate (cAMP) concentration.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
Introduction and Aim:  The corpus luteum is one of the most intensely vascularized tissues. Luteal angiogenesis is strictly controlled and blood vessels regress completely within a short period of time. The aim of this study was to investigate vascular dynamics in relation to cellular and molecular mechanisms of luteal angiogenesis and anti-angiogenesis.
Material and Methods:  Endothelial cells of blood vessels in paraffin sections of bovine corpora lutea from different stages were examined by labelling with the lectin Bandeiraea simplicifolia agglutinin I. Angiogenesis was studied by morphometry of the capillaries, and immunolocalization of the angiogenic factor VEGF and VEGF-receptor 2. Presence of apoptotic luteal and endothelial cells was investigated using the TUNEL test and transmission electron microscopy.
Results:  During development of the corpus luteum (day 3–8 of the oestrous cycle) a dense capillary network (8–12% area ratio) is established and maintained until day 17. Early regression (day 18–24) is characterized by a remarkable decrease of capillaries (1% area ratio). In the regressing corpus luteum the number of apoptotic luteal cells is closely correlated ( r  = 0.9) to the number of apoptotic endothelial cells. VEGF is immunolocalized in luteal cells (day 3–17), smooth muscle cells and endothelial cells of arterioles of the regressing corpus luteum. During late luteal regression, a moderate increase of capillaries (2.5% area ratio) is obvious.
Conclusions:  The dynamic changes of the capillarity during development and regression of the cyclic corpus luteum correlate with VEGF and VEGF-R2 activities. In contrary to expectations the late stage of luteal regression is accompanied by angiogenesis. One reason for this phenomenon may be an increase in metabolic activity resulting in re-organization of blood vessels already regressed.  相似文献   

9.
The objective of this study was to evaluate if treatment of equine chorionic gonadotrophin (eCG)-superovulated Sanjabi ewes with repeated administration of human chorionic gonadotropin (hCG) would increase the number of normal corpus luteum (CL) and serum progesterone concentrations and decrease the number of persistent follicles. The superovulated ewes were divided into four groups on day 0 (day of sponge removal); the ewes were treated by an intramuscular administration of 500?IU hCG on day 0 (Group I: n?=?10), on days 0 and 1 (Group II: n?=?10), or on days 0, 1, and 2 (Group III: n?=?10) and no treatment for control group (n?=?10). Blood samples were collected on days 0, 1, 2, 5, and 8 (day of slaughter), and serum progesterone concentrations were determined. According to progesterone concentrations, 50 (4/8) and 0?% of the ewes underwent premature luteal regression in the control group and the hCG groups, respectively. There were more CLs in Group III than in Group II and the control group. Ewes treated with hCG had a greater number of normal-looking CL. CL diameter was significantly greater in Group II and Group III than other groups. Total CL weight was significantly (P?<?0.05) higher in Group III than in Group I and the control group. Number of persistent follicle and persistent follicle diameter were lower in control group compared to the other groups. Eight days after sponge removal, serum progesterone concentration was significantly higher in Group III than in Group I and the control group. The present results indicate that repeated administration of hCG supported CL formation, increased serum progesterone concentration, and prevented premature luteal regression in eCG-superovulated Sanjabi ewes.  相似文献   

10.
Twenty-eight bitches with unknown reproductive histories were injected intravenously with either human chorionic gonadotrophin (hCG) or equine chorionic gonadotrophin (eCG) (pregnant mare's serum gonadotrophin) and their oestradiol responses were measured at the time of the injection and 90 minutes later. They were at various stages of the oestrous cycle as determined by histology and a progesterone assay for luteal function. Twenty-six of them were considered to be entire because they showed either an increase in plasma oestradiol over preinjection values or steady high values. The ovaries were removed from 25 of these animals and the other probably had a remnant of ovary because it came into oestrus some weeks later. In two remaining bitches no oestradiol could be detected either before or after the injection of gonadotrophin and they were predicted to have been neutered, which was confirmed at laparotomy. In the entire bitches, the highest plasma oestradiol concentration was measured during metoestrus and the lowest during anoestrus.  相似文献   

11.
The oestrus cycle in the domestic bitch, a monoestrous species, differs considerably from that of other veterinary domestic animals species. In the bitch the combined use of eCG and hCG is effective to induce oestrus predictably and safely (Stornelli et al., Theriogenology, 78, 2012 and 1056). Although several studies were done to describe the hormonal changes during the canine oestrus cycle, to our knowledge none was done to describe the hormonal changes during induced follicular growth after the administration of eCG. The aim of this work was to study prolactin (PRL), insulin‐like growth factor (IGF1) and androstenedione (ANDR) serum concentrations during follicular growth induced by a single dose of eCG administered to late anoestrous bitches. PRL and ANDR concentrations were lower before than after eCG TRT (before eCG vs pro‐oestrus, oestrus and dioestrus; 4.3 ± 1.8 ng/ml vs 6.5 ± 1.6 ng/ml, p < 0.05; 0.08 ± 0.2 ng/ml vs 0.42 ± 0.16 ng/ml, p < 0.05). Conversely, IGF1 concentrations were similar before and after eCG TRT (286.0 ng/ml ±32.2, p > 0.53). Additionally, PRL concentrations were similar before oestrus compared to during oestrus and dioestrus (6.9 ± 1.7 ng/ml, p > 0.19). Furthermore, IGF1 concentrations were higher before and during oestrus compared to first day of dioestrus (286.1 ± 29.8vs 200.4 ± 29.2 ng/ml, p < 0.01). On the contrary, ANDR concentrations were lower before and during oestrus compared to first day of diestrum (0.35 ± 0.17 ng/ml and 0.38 ± 0.15 vs 0.68 ± 0.17 ng/ml, p < 0.05). These results show that treatment with a single injection of 50 IU/kg of eCG in late anoestrous bitches successfully induced changes in follicular growth which were paralleled with changes in PRL, IGF1 and ANDR serum concentration similar to those occurring during a normally occurring oestrous cycle. In addition, our results suggest that IGF1 in the bitch could play an important role in ovarian folliculogenesis.  相似文献   

12.
The hypothesis that subnormal luteal function after induced ovulation in anestrous ewes was the result of uterine influences exerted during the periovulatory period was tested. Crossbred ewes (n = 27) in seasonal anestrus were induced to ovulate by administration of 12 doses of 250 ng of LHRH at 2-h intervals, followed immediately by a bolus injection of LHRH (250 micrograms; d 0). Ewes were unilaterally hysterectomized on either d -3 (PRELHRH) or 2 (POSTLHRH). Daily blood samples were collected and assayed for progesterone (P4) and 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM). All ewes were slaughtered on d 10, and corpora lutea (CL) were collected, weighed, and assayed for concentration of P4. All ewes that ovulated exclusively in the ovary ipsilateral to the remaining uterine horn had a transient increase in plasma P4 of 2 to 3 d (short luteal phase). In ewes with at least one CL in the isolated ovary, elevated plasma P4 was maintained after hysterectomy but was consistently lower (P less than .05) in POSTLHRH ewes than in PRELHRH ewes. Concentrations of PGFM did not differ between treatments. The CL ipsilateral to the remaining uterine horn weighted less (P less than .01) and contained less P4 (P less than .01) than contralateral CL. These data confirm the hypothesis that premature regression of subnormal CL is uterine-dependent in a local fashion. Presence of the uterus during the follicular and(or) early luteal phase inhibited subsequent luteal function in seasonally anestrous ewes.  相似文献   

13.
The effect of glucocorticoids on early follicular growth in sows undergoing normal estrous cycles was evaluated by administration of dexamethasone during the middle of the luteal phase. Plasma specimens were obtained for measurement of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone, and estradiol-17 beta concentrations. Fifteen sows were used. Control sows (n = 5) were given physiologic saline solution twice daily from day 9 to day 14 of the estrous cycle. Sows of the second group (n = 5) were given dexamethasone (30 micrograms/kg of body weight, IM) similarly, and those of the third group (n = 5) were given dexamethasone plus gonadotropin-releasing hormone (GnRH; 50 micrograms at 6-hour intervals, IV). Plasma specimens, obtained twice daily from day 8 through day 26, indicated that progesterone production and luteal regression were not inhibited by any of the 3 treatment regimens. Although preovulatory plasma estradiol concentration increased in control sows, such was not observed in the sows treated with dexamethasone or dexamethasone plus GnRH (P less than 0.01). Ovulation, with formation of corpora lutea, occurred in gilts given saline solution. Dexamethasone administration resulted in persistence of 19 to 41 follicles/ovary (2 to 4 mm in diameter), and dexamethasone-plus-GnRH treatment resulted in 6 to 18 follicles/ovary (5 to 6 mm in diameter). Plasma was obtained at 15-minute intervals for 12 hours to compare the effect of treatment on hormone concentrations on day 12 of the estrous cycle with the values on day 8.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
Some studies in mammalian species recently demonstrated that tumor necrosis factor (TNF)-alpha plays an important role for corpus luteum (CL) function by way of apoptosis during the estrous cycle. The objectives of this study were to clarify the induction of apoptosis in cultured porcine luteal cells by TNF-alpha treatment. Luteal cells prepared from porcine ovaries collected from crossbred mature gilts on Days 10-14 of the estrous cycle were isolated and examined as follows: 1) Flow cytometric analysis was carried out to determine apoptosis in cultured luteal cells. 2) Single-cell gel electrophoresis (comet assay) was performed to investigate apoptotic DNA fragmentation in luteal cells. The results of the flow cytometric analysis and comet assay demonstrated coincidentally that TNF-alpha induces DNA fragmentation in luteal cells causing apoptosis. These results revealed that TNF-alpha is an inducing factor of apoptosis in luteal cells.  相似文献   

15.
Structural luteolysis occurs by apoptosis of luteal cells. The present study examined the effects of activators of well-characterized second messengers on Fas and caspase-3 mRNA expression and on P4 production in luteal cells in order to trace the pro- and anti-apoptotic factors in the bovine corpus luteum (CL). Cultured bovine mid luteal cells were treated for 24 h with a cyclic AMP analogue (8-bromo cyclic AMP; 8br-cAMP; 2.5 mM), a protein kinase C (PKC) activator (phorbol 12-myristate 13-acetate; PMA; 10 microM), or calcium ionophore (A23187; 10 microM). Fas and caspase-3 mRNA expression was inhibited by 8br-cAMP and PMA but was increased by A23187 (P<0.05). In addition, P4 production by bovine luteal cells was stimulated by 8br-cAMP and PMA, whereas it was inhibited by A23187, compared with untreated controls (P<0.05). The overall results suggest that cAMP and PKC suppress apoptosis in bovine luteal cells through inhibition of Fas and caspase-3 mRNA expression and through stimulation of P4 production. Therefore, substances that activate cAMP or PKC may act as survival factors in the bovine CL. Furthermore, substances that mobilize Ca2+ may act as apoptotic factors by stimulating Fas and caspase-3 expression in the bovine luteal cells.  相似文献   

16.
Connexin 43 (Cx43) is the predominant gap junction protein within porcine ovary and is required for proper follicle and corpus luteum (CL) development. Recent research suggests maternally or neonatally mediated effects of antiandrogens on reproductive function during adulthood, notably those dependent on gap junctional communication. The current study was conducted to determine whether late gestational or neonatal exposure to the antiandrogen flutamide influences Cx43 gene expression in the adult porcine ovary. Flutamide was injected into pregnant gilts between days 80 and 88 of gestation and into female piglets between days 2 and 10 posnatally. After animals reached sexual maturity, the ovaries were collected from treated and nontreated (control) pigs. Expression of Cx43 mRNA and protein was determined for preantral and antral follicles and for CLs. In addition, 3β-hydroxysteroid dehydrogenase (3β-HSD) expression and progesterone concentration were determined for luteal tissues. In preantral follicles, Cx43 mRNA was down-regulated (P < 0.01) following maternal and neonatal flutamide exposure. In large antral follicles, Cx43 mRNA was up-regulated (P < 0.01) after neonatal flutamide administration. Immunofluorescence showed that Cx43 expression decreased (P < 0.001) in preantral follicles and increased (P < 0.001) in large antral follicles following flutamide exposure. In luteal tissues, Cx43 and 3β-HSD expression and progesterone concentration decreased (P < 0.01) after postnatal flutamide treatment. Overall, these results suggest the involvement of androgens in the regulation of Cx43 expression in pig ovary. Moreover, alteration of Cx43 expression by the administration of flutamide during particular prenatal and neonatal time periods may affect porcine follicle development, as well as CL formation and function.  相似文献   

17.
旨在研究黄体期不同阶段注射前列腺激素(PGF2α)对育成母羊生殖激素和生殖相关细胞因子的影响。本研究选择健康、体况良好、体重相近、发情周期正常的湖羊育成母羊60只,用“孕酮栓(MAP)+PMSG”法进行发情周期同步化处理后,选择发情正常的48只母羊随机均分为6组。发情当天记为第0天,黄体前期试验组、中期试验组和末期试验组母羊分别在第6(黄体前期)、11(黄体中期)、16天(黄体末期)注射1 mL PGF2α(0.1 mg),黄体前期对照组、中期对照组和末期对照组母羊分别在第6、11、16天注射1 mL生理盐水,每次注射后0.5、1、2、3 h采血,用于血液指标检测。结果表明,所有试验组和对照组母羊于注射后的0.5~3 h间血清中FSH、LH、PRL、P4、E2水平以及TNF-α、IL-1β、IL-6、IFN-β无显著变化(P＞0.05);母羊在黄体期不同阶段注射PGF2α对0.5、1、2、3 h血清中FSH、LH、PRL及IL-1β、IFN-β无显著影响(P＞0.05),前期试验组注射后3 h P4水平显著低于前期对照组,E2和IL-6水平显著高于前期对照组(P＜0.05),前期试验组注射后2和3 h TNF-α水平显著高于前期对照组(P＜0.05);中期试验组注射后1 h P4水平显著低于中期对照组(P＜0.05)。黄体前期注射PGF2α后,前期试验组0.5~ 3 h内FSH、E2、TNF-α、IL-6整体水平显著高于前期对照组(P＜0.05),P4整体水平显著低于前期对照组(P＜0.05),对LH、PRL、IL-1β和IFN-β无显著影响(P＞0.05);黄体中期注射PGF2α后,中期试验组0.5~3 h内E2整体水平显著高于中期对照组(P＜0.05),P4整体水平显著低于中期对照组(P＜0.05),对FSH、LH、PRL、TNF-α、IL-1β、IL-6和IFN-β无显著影响(P＞0.05);黄体末期注射PGF2α对生殖激素与相关细胞因子没有显著性影响(P＞0.05)。本研究结果表明,PGF2α对黄体的溶解作用存在阶段性差异,母羊在黄体前期对PGF2α的短期应答反应强于黄体中、末期,且黄体前期时,卵巢可以响应PGF2α为卵泡发育营造更佳的发育环境。  相似文献   

18.
The present experiment aims to examine the efficiency of estrus synchronization using progesterone and equine chorionic gonadotrophin (eCG) and to look at luteal function. During the non-breeding and breeding season, 5 adult female Korean native goats were injected intramuscularly with 2.5 ml of physiological saline as the control. A progesterone impregnated intravaginal sponge was then kept in the same goats for 10 days followed, after a week, by an intramuscular injection of 500 IU eCG. Five adult female Nubian goats were mated with a fertile buck during the non-breeding season. During the non-breeding season 2 of the 5 goats showed a normal estrous cycle (ranging from 18 to 21 days) and 3 a short estrous cycle (ranging from 3 to 6 days). During the breeding season the equivalent figures were 1 and 2. The major axes of the corpus luteum (CL) were measured by means of calipers built into the ultrasonography system, and the concentrations of plasma progesterone (P4) were determined by double antibody radioimmunoassay. The mean major axes of the CL in goats showing the short cycle (6.1 ± 0.5 mm) was significantly smaller than in those showing the normal cycle (8.9 ± 0.5 mm; p < 0.01) and also the value of P4 in goats showing the short cycle (4.2 ± 2.1 ng/ml) was significantly lower than for those showing the normal cycle (10.3 ± 4.3 ng/ml; p < 0.05) at day 3 following ovulation. Three out of 5 Nubian goats became pregnant but only one goat carried to full term. The present experiment indicated that a combination of progesterone and eCG was effective in inducing estrus, although it resulted in a high incidence of short luteal lifespan. The low kidding rate and high incidence of embryonic loss may be due to the instability of the luteal lifespan.  相似文献   

19.
We examined the ovaries of 44 Wistar Hannover (RccHanTM:WIST) (WH) and 30 Sprague-Dawley (SD) rats at 32-weeks of age to determine whether the ovarian structure and formation/regression of the corpora lutea (CLs) differ between the two strains. The average ovary weight was higher in WH rats. The average number of all CLs, including currently formed and previously formed CLs, was higher in WH rats in all cycles; however, no appreciable difference was detected in the number of newly or currently formed CLs between the two strains. CLs regression characterized by degeneration and necrosis of luteal cells began to appear in diestrus in both strains; however, the distribution of degenerated/necrotic cells in CLs differed. Necrotic cells were scattered in SD rats but were focally observed in the center of the CL in WH rats. The reduction in size of previously formed CLs accompanied by regression started about 2 or more stages later in WH rats than in those of SD rats. In conclusion, the higher number of CLs in WH rats is considered to be due to slow CL regression compared with in SD rats.  相似文献   

20.
The study evaluated, in early post‐partum anoestrous Nelore cows, if the increase in plasma oestradiol (E2) concentrations in the pre‐ovulatory period and/or progesterone priming (P4 priming) preceding ovulation, induced by hormonal treatment, reduces the endogenous release of prostaglandin PGF2αand prevents premature lysis of the corpus luteum (CL). Nelore cows were subjected to temporary calf removal for 48 h and divided into two groups: GPE/eCG group (n = 10) and GPG/eCG group (n = 10). Animals of the GPE/eCG group were treated with a GnRH agonist. Seven days later, they received 400 IU of eCG, immediately after PGF2α treatment, and on day 0, 1.0 mg of oestradiol benzoate (EB). Cows of the GPG/eCG group were similarly treated as those of the GPE/eCG group, except that EB was replaced with a second dose of GnRH. All animals were challenged with oxytocin (OT) 9, 12, 15 and 18 days after EB or GnRH administration and blood samples were collected before and 30 min after OT. Irrespective of the treatments, a decline in P4 concentration on day 18 was observed for cows without P4 priming. However, animals exposed to P4 priming, treated with EB maintained high P4 concentrations (8.8 ± 1.2 ng/ml), whereas there was a decline in P4 on day 18 (2.1 ± 1.0 ng/ml) for cows that received GnRH to induce ovulation (p < 0.01). Production of 13,14‐dihydro‐15‐keto prostaglandin F2α (PGFM) in response to OT increased between days 9 and 18 (p < 0.01), and this increase tended to be more evident in animals not exposed to P4 priming (p < 0.06). In conclusion, the increase in E2 during the pre‐ovulatory period was not effective in inhibiting PGFM release, which was lower in P4‐primed than in non‐primed animals. Treatment with EB promoted the maintenance of elevated P4 concentrations 18 days after ovulation in P4‐primed animals, indicating a possible beneficial effect of hormone protocols containing EB in animals with P4 priming.  相似文献   

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