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1.
W J Murdoch 《Domestic animal endocrinology》1992,9(3):219-224
An experimental model was established in the ewe allowing one to predict with accuracy an antral follicle that coincidentally would either undergo ovulation (6-8 mm diameter) or atresia (3-4 mm diameter) following synchronization of luteal regression and the onset of the gonadotropin surge. Quantitative morphometric and hormonal criteria were used to make direct comparisons of such follicles collected throughout the preovulatory period. There were progressive alterations in percentages of granulosa cells exhibiting pyknotic nuclei, dispersion of granulosa cells, oocyte maturation, thecal vascular dynamics and extravasation of leukocytes. Nevertheless, no significant variations in temporal patterns were observed between follicular classification. The most notable anatomical distinction between preovulatory and atretogenic follicles was that the former had come into closer contact with the ovarian surface epithelium. The dominant follicle had a higher capacity than the subordinate follicle to produce estradiol before the gonadotropin surge; however, ensuing profiles of steroidogenic function (i.e., shift from the delta 5 to delta 4 pathway) occurred in parallel. Thus, in many respects the follicular mechanics of ovulation and atresia in the sheep appear analogous. 相似文献
2.
《Domestic animal endocrinology》1994,11(1):59-86
Crossbred heifers (n = 103) were synchronized to estrus with prostaglandin (PGF2α) and superovulated with follicle stimulating hormone (FSH-P). Animals were ovariectomized every 12 hr after the PGF2α injection (n = 7 to 9/time) up to 108 hr to monitor the follicular, hormonal, and oocyte changes associated with follicular development and ovulation. Twenty-eight animals were implanted with Norgestomet implants 12 hr before PGF2α and ovariectomized at 72, 84, 96, and 108 hr post PGF2α injection to monitor effects of progesterone and suppression of the luteinizing hormone (LH) surge on oocyte maturation and quality. Follicular fluid was collected and analyzed for progesterone, estradiol, prolactin, and glycosaminoglycan content in conjunction with cumulus maturation and nuclear stage of oocyte maturation. Analysis of in vivo matured oocytes by in vitro fertilization was carried out at 60, 72, 84, and 96 hr post PGF2α and in vitro matured oocytes at 12 to 108 hr post PGF2α. No developmental changes in cumulus cells surrounding the oocyte of small follicles was noted (≤ 4 mm dia) indicating a static population. Medium (> 4 ≤ 8 mm) and large size (> 8 mm) follicles developed to the corona radiata and loose cumulus stages in animals in which an LH surge was detected but cumulus status remained primarily in the tight cumulus stage for animals without an LH surge. The estradiol-to-progesterone ratio for tight cumulus (TC), corona radiata (CR), and loose cumulus (LC) stages was 1.8 ± .1, 1.0 ± .1, and .4 ± .2, respectively (P < .01). Nuclear maturation of oocytes in small follicles from animals without a detectable LH surge seem to indicate early maturation (48 to 72 hr post PGF2α) in conjunction with a high percent of degenerate oocytes not seen in animals exhibiting an LH surge. Oocytes from medium size follicles matured to germinal vesicle breakdown (GVBD) and early meiosis (metaphase I; MI) stages of development in all treatments. Most oocytes were degenerate in Norgestomet-implanted animals. Oocytes from large follicles (> 8 mm dia) from animals exhibiting an LH surge were in MI and metaphase II (MII) stages (48 to 84 hr post PGF2α) in preparation of ovulation whereas oocytes from animals not exhibiting an LH surge had oocytes that early matured to MII (48 to 72 hr post PGF2α), later regressing to degenerate oocytes (84 to 108 hr). Follicular progesterone, estradiol, and prolactin increased with oocyte maturation, particularly in medium and large follicles. In vivo matured oocytes for fertilization (60, 72, 84, and 96 hr post PGF2α) were nude (from the oviduct) and primarily CR from follicles. Tubal oocytes (37%) were fertilized more frequently by a single sperm than follicular oocytes (14.3%; P < .01) and single sperm penetration peaked at 72 hr post PGF2α. Follicular hormone concentrations were not related to sperm penetration. Oocytes (n = 101) matured in vivo had lower fertilization potential from ovaries producing < 14 or > 50 follicles (39.3%) as compared to 21 to 45 aspirated follicles (68.2%; P < .05), with a peak penetration at 32 follicles (86.7% penetration). No treatment differences (LH surge or no detectable LH surge) were noted in relation to in vivo matured oocytes. Oocytes with single sperm penetration had the lowest estradiol/progesterone ratio of 2.2 vs polyspermic penetration of 13.7. 相似文献
3.
Progesterone is critical for successful ovulation in the ovary and for the multi-faceted role of the oviduct in mammalian reproduction. Its effects are mediated by progesterone receptor (PGR), which is highly expressed in the ovary, specifically granulosa cells of preovulatory follicles in response to the luteinizing hormone (LH) surge that occurs just prior to ovulation, and in the oviduct, predominantly luminal epithelial cells but also muscle cells. This review will summarize research which shows that progesterone, via the actions of PGR, plays a key role in the functions of these cells and in the important periovulatory events of oocyte release, acquisition of oocyte developmental competence and oviductal transport of the newly formed embryo. PGR is a nuclear receptor that regulates the expression of many downstream target genes. However, although much is known about its expression characteristics in ovarian and oviductal cells, there is still much to unravel about the mechanisms by which PGR exerts its control over these important reproductive processes, particularly in the oviduct. 相似文献
4.
Periovulatory endocrinology and oocyte maturation in unmated mature blue fox vixens (Alopex lagopus)
W Farstad M Mondain-Monval P Hyttel A J Smith D Markeng 《Acta veterinaria Scandinavica》1989,30(3):313-319
Nine of 10 mature blue fox vixens (Alopex lagopus) in spontaneous oestrus ovulated approximately 2 days after the preovulatory increase in luteinizing hormone (LH). Plasma concentrations of follicle-stimulating hormone and progesterone increased simultaneously with the LH peak, whereas oestradiol-17 beta peaked 1 day previously. In the tenth vixen, an LH peak was not observed, and neither visible follicles nor corpora lutea were found in the ovaries 6 days after peak vaginal electrical resistance. Eggs were ovulated as primary oocytes, but oocyte maturation was initiated within the day of ovulation (2 days after the LH peak). Within the next 2 days (3-4 days after the LH peak) the first polar body was extruded, and the cumulus mass was completely dissociated from the zona pellucida. The interval between the preovulatory LH peak and initiation of the final oocyte maturation is thus considerably longer in the blue fox than for example in the cow (48-72 h compared with 9-12 h). This suggests that the relationship between these two events is somewhat different in the blue fox. 相似文献
5.
用取自 ３～５ ｍ ｍ 卵泡的处于减数分裂阻抑状态的猪卵丘卵母细胞复合体（ｐ Ｃ Ｅ Ｏ），培养 ４８ ｈ，用 Ｆ Ｓ Ｈ（１００ Ｉ Ｕ／ Ｌ）或 ｈ Ｃ Ｇ（０、５０、１００、２００、５００ Ｉ Ｕ／ Ｌ）刺激 ｐ Ｃ Ｅ Ｏ 分泌甾体激素；用放射受体测定法（ Ｒ Ｒ Ａ）比较 ｐ Ｃ Ｅ Ｏ 的卵丘细胞及壁层颗粒细胞（ Ｍ Ｇ Ｃ）上促黄体激素受体／人绒毛膜促性腺激素受体（ Ｌ Ｈ Ｒ／ｈ Ｃ Ｇ Ｒ）的数量； Ａ Ｍ ｅ Ｘ 石蜡切片、免疫组织化学染色，检测 Ｌ Ｈ Ｒ／ｈ Ｃ Ｇ Ｒ 在 ｐ Ｃ Ｅ Ｏ 以及 Ｍ Ｇ Ｃ 的分布情况。在 Ｆ Ｓ Ｈ 作用下，ｐ Ｃ Ｅ Ｏ 分泌的孕酮明显高于 ｈ Ｃ Ｇ 作用组和对照组 （ Ｐ ＜ ００５）； 平均每个壁层颗粒细胞上的 Ｌ Ｈ Ｒ／ｈ Ｃ Ｇ Ｒ是每个卵丘细胞的 １０５ 倍； Ｌ Ｈ Ｒ／ｈ Ｃ Ｇ Ｒ 在基膜两侧分布较多，且卵母细胞上没有 Ｌ Ｈ Ｒ／ｈ Ｃ Ｇ Ｒ，临近卵母细胞的卵丘细胞膜上较少被染色。以上结果表明，在体外试验中，可能由于 Ｃ Ｅ Ｏ 上 Ｌ Ｈ Ｒ／ｈ Ｃ Ｇ Ｒ 的数量不足或生理活性降低， Ｌ Ｈ／ｈ Ｃ Ｇ 不能促进卵母细胞恢复减数分裂。 相似文献
6.
Li M Liang CG Xiong B Xu BZ Lin SL Hou Y Chen DY Schatten H Sun QY 《Domestic animal endocrinology》2008,34(4):360-371
Previous studies have shown that epidermal growth factor (EGF) has the ability to promote in vitro cultured porcine oocyte maturation. However, little is known about the detailed downstream events in EGF-induced meiotic resumption. We designed this study to determine the relationship of EGF, EGFR, phosphatidylinositol 3-kinase (PI3-kinase), MAPK, and germinal vesicle breakdown (GVBD) during oocyte maturation. Our results showed that GVBD in cumulus-enclosed oocytes (CEOs) but not in denuded oocytes (DOs) was induced by EGF in a dose-dependent manner, which indicated that cumulus cells but not oocyte itself were the main target for EGF-induced meiotic resumption. Furthermore, we found that MAPK in cumulus cells rather than in oocyte was activated immediately after EGF administration. To explore whether EGF exerts its functions through MAPK pathway, the activities of EGF receptor (EGFR) and MAPK were inhibited by employing AG1478 and U0126, respectively. Inhibition of MAPK blocked EGF-induced GVBD, whereas inhibition of EGFR prevented MAPK activation. Both AG1478 and U0126 could lead to the failure of EGF-induced GVBD singly. Notably, we found that LY294002, a specific inhibitor of PI3-kinase, effectively inhibited EGF-induced MAPK activation as well as subsequent oocyte meiotic resumption and this inhibition could not be reversed by adding additional EGF. Thus, PI3-kinase-induced MAPK activation in cumulus cells mediated EGF-induced meiotic resumption in porcine CEOs. Together, this study provides evidences demonstrating a linear relationship of EGF/EGFR, PI3-kinase, MAPK and GVBD and presents a relatively definitive mechanism of EGF-induced meiotic resumption of porcine oocyte. 相似文献
7.
Bmp/Smad信号通路及其在哺乳动物卵巢发育中的作用 总被引：1，自引：0，他引：1
《中国畜牧杂志》2019,(8)
开展绵羊多羔性状基因的研究对于揭示其分子调控机制和提高绵羊繁殖力具有重要意义。骨形态发生蛋白(BMPs)为转化生长因子-β(TGF-β)超家族成员,与哺乳动物繁殖活动密切相关。研究表明,BMPs可促使原始卵泡向次级卵泡转化,对哺乳动物卵巢颗粒细胞增殖、生殖激素的合成和分泌以及卵母细胞成熟和排卵等方面起重要调节作用,而BMPs发挥功能主要依赖于经典的Bmp/Smad信号通路。本文就Bmp/Smad信号通路成员的表达、对早期胚胎发育的影响以及在哺乳动物卵巢发育中的作用等方面的研究进行总结,以期为进一步研究BMPs及其信号通路的调控机制提供参考。 相似文献
8.
9.
Mechanistic target of rapamycin is activated in bovine granulosa cells after LH surge but is not essential for ovulation 
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下载免费PDF全文 PRA da Rosa AMP Dau MP De Cesaro JT dos Santos BG Gasperin R Duggavathi V Bordignon PBD Gonçalves 《Reproduction in domestic animals》2016,51(5):766-773
The LH surge induces functional and morphological changes in granulosa cells. Mechanistic target of rapamycin (mTOR) is an integrator of signalling pathways in multiple cell types. We hypothesized that mTOR kinase activity integrates and modulates molecular pathways induced by LH in granulosa cells during the preovulatory period. Cows were ovariectomized and granulosa cells collected at 0, 3, 6, 12 and 24 hr after GnRH injection. While RHEB mRNA levels increased at 3 and 6 hr, returning to basal levels by 12 hr after GnRH treatment, RHOA mRNA levels increased at 6 hr and remained high thereafter. Western blot analyses revealed increased S6K phosphorylation at 3 and 6 hr after GnRH injection. Similarly, mRNA levels of ERK1/2, STAR and EGR‐1 were higher 3 hr after GnRH treatment. Rapamycin treatment inhibited mTOR activity and increased AKT activity, but did not alter ERK1/2 phosphorylation and EGR1 protein levels in cultured bovine granulosa cells. Rapamycin also inhibited LH‐induced increase in EREG mRNA abundance in granulosa cells in vitro. However, intrafollicular injection of rapamycin did not suppress ovulation. These findings suggest that mTOR is involved in the control of EREG expression in cattle, which may be triggered by LH surge stimulating RHEB and S6K activity. 相似文献
10.
A Veiga-Lopez T Encinas A S McNeilly A Gonzalez-Bulnes 《Reproduction in domestic animals》2008,43(1):92-98
The aims of this study were to evaluate the chronology of periovulatory events (oestrus behaviour, LH surge and ovulation) in 16 superovulated Manchega sheep and to determine whether follicular status at start of the FSH supply might affect their occurrence. Mean timing for onset of oestrus behaviour was detected at 28.1 +/- 0.7 h after sponge withdrawal; the preovulatory LH surge and ovulation started at 37.2 +/- 0.7 h and 65.4 +/- 0.7 h after progestagen withdrawal, respectively. The intervals between oestrus, LH surge and ovulation were affected by a high individual variability, which might be the cause for reported decreased efficiency in embryo production. Current results also addressed the role of follicular status at start of the superovulatory treatment on the preovulatory LH surge and the ovulation. The interval LH surge-ovulation was increased in ewes with a growing dominant follicle at starting the FSH treatment (32.3 +/- 0.9 vs 28.6 +/- 0.5 h, p < 0.05). The developmental stage of the largest follicle at starting the superovulatory treatment also affected occurrence of LH surge and ovulation; follicles in growing phase advanced the occurrence of the LH surge and ovulation when compared to decreasing follicles (33.0 +/- 1.0 vs 43.5 +/- 1.1 h, p < 0.05, for LH peak and 60.7 +/- 1.1 vs 72.8 +/- 1.2 h, p < 0.05, for ovulation). Thus, only ewes with growing follicles ovulated prior to 55 h after sponge withdrawal; conversely, no sheep with decreasing follicles ovulated earlier than 67 h, when an 85.7% of the ewes bearing growing follicles has ovulated at 63 h. 相似文献
11.
Epidermal growth factor (EGF) has been shown to have a positive effect during oocyte in vitro maturation in several species. This study was performed to establish the capacity of equine oocytes to undergo nuclear maturation in the presence of EGF and to localise its receptor in the equine ovary by immunohistochemical methods. Oocytes were obtained by aspiration and subsequent scraping from equine follicles (15-25 mm diameter) and cultured in 3 different treatment groups for 36 h: control Group (modified TCM 199 with 0.003% BSA), EGF Group (TCM-199 supplemented with 50 ng/ml EGF) and EMS Group (TCM 199 supplemented with 10% v/v oestrous mare serum). Each group was divided further into 3 treatments with tyrphostin A-47, a specific tyrosine kinase inhibitor, at 0, 10(-4) and 10(-6) mmol/l. Maturation was determined as the percentage of oocytes reaching metaphase II stage at the end of the culture period. Immunohistochemical detection of EGF-receptor (EGFR) was performed using a streptoavidin-biotin method. The recovery rate and oocyte retrieval were 84.6% (recovered oocytes/follicles aspirated) and 6.55 (oocytes/mare), respectively. Treatment with EGF significantly (P<0.05) increased the incidence of metaphase II stage compared with the control group (69.4 vs. 26.9% in controls, respectively). The specific-tyrosine kinase inhibitor A-47 was effective in suppressing EGF-effect on EGF-cultured oocytes; no significant differences were observed in EMS-supplemented oocytes when cultured with A-47. EGF-receptor was localised in follicles, with localisation being more prominent in the cumulus than in mural granulosa cells. This finding, together with the increase of oocyte nuclear maturation rate when using EGF in culture media and the inhibition of maturation by tyrphostin A-47, suggests a physiological role for EGF in the regulation of equine oocyte maturation. The results should help successful development of assisted reproductive technology in the horse. 相似文献
12.
Luteinizing hormone (LH) stimulates a cascade of ovarian hormonal events that culminate in ovulation. This study was designed to investigate, in sheep, sequential changes in prostaglandin (PG) E2, PGF2 alpha, 6-keto-PGF1 alpha, and cyclic adenosine monophosphate (cAMP) in the theca, granulosa and follicular fluid of large preovulatory follicles and small nonovulatory follicles in response to LH. On d 15 postestrus, preovulatory or nonovulatory follicles were injected intrafollicularly with saline or LH. Ewes were then ovariectomized at 0, 2, 4, or 8 h postinjection. Injected follicles were excised; theca, granulosa and fluid were separated, weighed and assayed for cAMP and PG. Contents of cAMP in the theca, granulosa and fluid of preovulatory follicles increased (P less than .01) 2 to 4 h after injection of LH. Increases (P less than .05) in contents of PGE2 and PGF2 alpha in the theca and fluid of preovulatory follicles were observed between 4 and 8 h after injection of LH. The time courses of LH-induced synthesis of PGE2 and PGF2 alpha in preovulatory follicles were parallel. Luteinizing hormone had no effect on PGE2, PGF2 alpha or cAMP in any compartment of small follicles. Contents of 6-keto-PGF1 alpha varied with time in both theca and granulosa of large and small, saline- and LH-injected follicles. Although specific increases in cAMP and PG followed an injection of LH only in large follicles, the parallel temporal relationship of PGE2 and PGF2 alpha did not explain the dichotomous functions ascribed to PGE2 and PGF2 alpha during the periovulatory period. 相似文献
13.
The aim of this study was to investigate steroidogenesis within porcine cumulus oocyte complexes during in vitro maturation and to examine the possible influence of the mitogen-activated protein kinase (MAPK). Porcine cumulus oocyte complexes were matured in vitro with and without the MAPK kinase inhibitor U0126 for 0, 5, 26 and 46 h. The 17β-estradiol and progesterone concentration in the culture medium were then determined. In addition, the mRNA levels of StAR, Cyp11A1, 3β-HSD and Cyp19A1 in cumulus cells were analysed by RT-PCR. Using an immunoblot, the MAPK phosphorylation in cumulus cells and oocytes was examined. During the first 26 h of in vitro maturation, 17β-estradiol secretion was predominant, whereas, after a culture period of 46 h, the progesterone secretion decreased conspicuously. Under the influence of U0126, the secretion of 17β-estradiol increased progressively during the complete maturation period, while progesterone secretion was completely inhibited. The mRNA levels of StAR and Cyp11A1 were not altered by U0126; however, corresponding to the hormone secretion, the gene expression of Cyp19A1 was up-regulated and the expression of 3β-HSD down-regulated. The results suggested an influence of the MAPK on steroidogenesis in cumulus cells comparable to a luteinization factor. Hormone synthesis in cumulus cells during oocyte maturation seems to be regulated by altering expression of Cyp19A1 and 3β-HSD. 相似文献
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15.
Tosca L Chabrolle C Crochet S Tesseraud S Dupont J 《Domestic animal endocrinology》2008,34(2):204-216
IGF-1 plays a key role in the proliferation and differentiation of granulosa cells. However, the molecular mechanism of IGF-1 action in avian granulosa cells during follicle maturation is unclear. Here, we first studied IGF-1 receptor (IGF-1R) expression, IGF-1-induced progesterone production and some IGF-1R signaling pathways in granulosa cells from different follicles. IGF-1R (mRNA and protein) was higher in fresh or cultured granulosa cells from the largest follicles (F1 or F2) than in those from smaller follicles (F3 or F4). In vitro, IGF-1 treatment (10(-8)M, 36h) increased progesterone secretion by four-fold in mixed F3 and F4 (F3/4) granulosa cells and by 1.5-fold in F1 granulosa cells. IGF-1 (10(-8)M, 30min)-induced increases in tyrosine phosphorylation of IGF-1R beta subunit and phosphorylation of ERK were higher in F1 than in F3/4 granulosa cells. Interestingly, IGF-1 stimulation (10(-8)M, 10min) decreased the level of AMPK Thr172 phosphorylation in F1 and F3/4 granulosa cells. We have recently showed that AMPK (AMP-activated protein kinase) is a protein kinase involved in the steroidogenesis in chicken granulosa cells. We then studied the effects of AMPK activation by AICAR (5-aminoimidazole-4-carboxamide ribonucleoside), an activator of AMPK, on IGF-1-induced progesterone secretion by F3/4 and F1 granulosa cells. AICAR treatment (1mM, 36h) increased IGF-1-induced progesterone secretion, StAR protein levels and decreased ERK phosphorylation in F1 granulosa cells. Opposite data were observed in F3/4 granulosa cells. Adenovirus-mediated expression of dominant negative AMPK totally reversed the effects of AICAR on IGF-1-induced progesterone secretion, StAR protein production and ERK phosphorylation in both F3/4 and F1 granulosa cells. Thus, a variation of energy metabolism through AMPK activation could modulate differently IGF-1-induced progesterone production in F1 and F3/4 granulosa cells. 相似文献
16.
Canine pregnancy and parturition 总被引：2，自引：0，他引：2
P W Concannon 《Veterinary Clinics of North America: Small Animal Practice》1986,16(3):453-475
In contrast to the large variation in canine gestation lengths based on mating-to-whelping intervals (56 to 70 days), gestation length based on intervals from the preovulatory LH surge to whelping shows little variation (64 to 66 days). By considering the preovulatory LH surge as the central endocrine event of the fertile cycle, various events can be reasonably timed, including ovulation on day 2, oocyte maturation on day 4, reduced fertility after day 6, implantation around day 17, and development of fetal radiopacity after day 45. Throughout pregnancy, gestation is dependent on ovarian progesterone secretion and, thus, on pituitary LH and prolactin for luteotrophic support. Because prostaglandin F2 alpha is luteolytic in the bitch, it may be involved in the luteolysis observed immediately prepartum in association with rises in maternal cortisol and prolactin levels. 相似文献
17.
Bajram Berisha Dieter Schams Fred Sinowatz Daniela Rodler Michael W. Pfaffl 《Reproduction in domestic animals》2020,55(11):1573-1584
The objective of the study was to characterize expression patterns of hypoxia-inducible factor-1alpha (HIF1A), inducible nitric oxide synthase (iNOS) and endothelial (eNOS) isoforms in time-defined follicle classes before and after GnRH application in the cow. Ovaries containing pre-ovulatory follicles or corpora lutea were collected by transvaginal ovariectomy (n = 5 cows/group) as follow: (I) before GnRH administration; (II) 4h after GnRH; (III) 10h after GnRH; (IV) 20h after GnRH; (V) 25h after GnRH; and (VI) 60h after GnRH (early corpus luteum). The mRNA abundance of HIF1A in the follicle group before GnRH was high, followed by a significant down regulation afterwards with a minimum level 25h after GnRH (close to ovulation) and significant increase only after ovulation. The mRNA abundance of iNOS before GnRH was high, decreased significantly during LH surge, with minimum levels afterwards. In contrast, the mRNA of eNOS decreased in the follicle group 20h after GnRH, followed by a rapid and significant upregulation just after ovulation. Immunohistochemically, the granulosa cells of antral follicles and the eosinophils of the theca tissue as well of the early corpus luteum showed a strong staining for HIF1A. The location of the eosinophils could be clearly demonstrated by immunostaining with an eosinophil-specific antibody (EMBP) and transmission electron microscopy. In conclusion, the parallel and acute regulated expression patterns of HIF1A and NOS isoforms, specifically during the interval between the LH surge and ovulation, indicate that these paracrine factors are involved in the local mechanisms, regulating final follicle maturation, ovulation and early luteal angiogenesis. 相似文献
18.
卵泡从原始卵泡发育为成熟卵泡，直至排卵、黄体发育等过程都受到精密的调控，产生大量的优势卵泡是绵羊产多羔及实现快速扩繁的关键因素。研究发现，相关信号通路和转录因子通过影响绵羊卵泡中卵母细胞、颗粒细胞的生长，进而调控卵泡的发育成熟，对这些信号通路进行深入了解，有助于探索卵泡发育的调控机制，早日实现绵羊高效繁育。Notch是卵泡发育过程中发挥重要作用的高度保守信号通路，PI3K/AKT/mTOR信号通路各成员都是广泛存在于细胞内的信号转导分子，在卵泡发育早期发挥了主要作用，还有间隙连接（gap junction，GJ）和跨带突触（transzonal projections，TZPs）等物理连接方式，在细胞间的交流通讯起到重要作用。作者详细介绍了Notch信号通路、PI3K/AKT/mTOR信号通路、间隙连接及跨带突触的结构功能在绵羊卵泡发育中的调控作用，为进一步探明绵羊卵泡发育的调控机制提供参考。 相似文献
19.
In the present study, we investigated the effects of adding luteinizing hormone (LH) to a medium containing follicle stimulating hormone (FSH) on the shift in expression of progesterone receptor (PR) isoforms (PR‐A and PR‐B) and the roles in function of cumulus cells of cumulus‐oocyte complexes (COC). The level of PR‐B mRNA in cumulus cells was up‐regulated by FSH during the first 16‐h cultivation but the level was significantly decreased at 20 h. The decrease of PR‐B mRNA was accelerated when COC were cultured with FSH and LH. Still, a high level of total PR mRNA was maintained in cumulus cells cultured with or without the addition of LH up to 20 h, suggesting that the expression of PR isoforms was shifted from PR‐B to PR‐A in cumulus cells. The reduction of PR‐B was also induced by addition of progesterone to FSH‐containing medium. The addition of LH or progesterone to FSH‐containing medium stimulated cumulus expansion of COC as compared with that of COC cultured with FSH. In the expanded COC, ADAMTS‐1 which is expressed in granulosa cells and cumulus cells in rodent follicles through LH‐induced progesterone‐ and PR‐dependent pathway, was more accumulated within the COC matrix. These results suggest that the addition of LH or progesterone to FSH‐containing medium is required for the differentiation of cumulus cells, such as cumulus expansion, mediated by the shift from PR‐B to PR‐A in them. 相似文献