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1.
The aim of the current study was to determine the possible effects of progestagen oestrous synchronization on vascular endothelial growth factor (VEGF) expression during sheep luteogenesis and the peri‐implantation period and the relationship with luteal function. At days 9, 11, 13, 15, 17 and 21 of pregnancy, the ovaries from 30 progestagen treated and 30 ewes cycling after cloprostenol injection were evaluated by ultrasonography and, thereafter, collected and processed for immunohistochemical evaluation of VEGF; blood samples were drawn for evaluating plasma progesterone. The progestagen‐treated group showed smaller corpora lutea than cloprostenol‐treated and lower progesterone secretion. The expression of VEGF in the luteal cells increased with time in the cloprostenol group, but not in the progestagen‐treated group, which even showed a decrease between days 11 and 13. In progestagen‐treated sheep, VEGF expression in granulosa‐derived parenchymal lobule capillaries was correlated with the size of the luteal tissue, larger corpora lutea had higher expression, and tended to have a higher progesterone secretion. In conclusion, the current study indicates the existence of deleterious effects from exogenous progestagen treatments on progesterone secretion from induced corpora lutea, which correlate with alterations in the expression of VEGF in the luteal tissue and, this, presumably in the processes of neoangiogenesis and luteogenesis.  相似文献   

2.
The aim of the present study was to evaluate the effects of cholesterol on progesterone production during long‐term culturing of luteal cell subpopulations at early and late luteal stages of the goat corpora lutea. Corpora lutea were collected from Angora goats on days 5 and 15 of the oestrous cycle. Luteal cells were isolated by collagenase digestion. The cells were separated into two distinct subpopulations by Percoll density‐gradient centrifugation. Both subpopulations of luteal cells staining positively for 3β‐HSD activities (5 × 104 cell/well) were cultured with or without 22(R)‐hydroxycholesterol (22R‐HC) in serum‐free culture medium for periods of up to 7 days. Cells were incubated with serum (10%) for the first 18 h of incubation followed by serum‐free medium. Cell treatment (10 and 20 μg/ml) was performed on days 1, 3 and 5. Treatment of cells with both concentrations of 22R‐HC resulted in significant (p < 0.01) and dose‐dependent stimulation (p > 0.05) on progesterone production in both fractions of cells throughout 7 days of incubation. Treatment of the cells with cholesterol resulted in 2.5‐ and 9.0‐fold increases in progesterone accumulation on day 3 of incubation. Steroid production was maintained throughout the incubations when cells are incubated in serum‐free media treated with cholesterol and ITS premix. Cells collected from higher density of percoll layers produced 2.82 and 2.32 times more progesterone, in comparison to the lover density percoll layer, on days 5 and 15 of the oestrous cycle in untreated cell groups, respectively. Progesterone accumulation was decreased as incubation time advanced in all groups of untreated cells. These results demonstrated that goat luteal cell subpopulations secrete substantial amounts of progesterone in response to cholesterol treatment at least for 7 days, and cholesterol is required as progesterone precursor for maintaining a high‐level steroidogenesis during long‐life culturing of both cell subpopulations.  相似文献   

3.
The ability of ovine placental lactogen (oPL) to stimulate progesterone secretion of porcine luteal cells isolated from ovaries in different stages of the oestrous cycle and to support the luteotropic action of PGE2 or to protect the corpus luteum (CL) against the luteolytic action of PGF2 alpha was investigated. oPL in all doses used had no effect on progesterone production of cells isolated from early developing corpora lutea while in doses of 1 and 10 ng/ml it increased oestradiol secretion by this type of cells. In doses of 1, 10 and 100 ng/ml it also increased progesterone secretion of cells isolated from mature corpora lutea in a dose-dependent manner. No influence on progesterone production of cells isolated from regressing corpora lutea was observed. oPL added to the culture media had no effect on PGE2-stimulated progesterone production by cells isolated from mature corpora lutea. However, it exerted a protective effect against the luteolytic action of PGF2 alpha observed in cultures treated with PGF2 alpha alone or in combination with PGE2 in a ratio of 4:1. These studies provide evidence that oPL is luteotropic and supports progesterone production in swine. The fact that oPL acted directly on ovarian steroidogenesis suggests that it may also play some role under non-pregnant physiological conditions. Future studies of structural and functional proteins secreted by the porcine conceptus will help resolve this uncertainty.  相似文献   

4.
The aim of this study was to examine the effect of β‐carotene supply during the close‐up dry period on the onset of first postpartum luteal activity in dairy cows. Twelve cows were supplied with 2000 mg of β‐carotene (20 g Rovimix®β‐Carotene containing 10%β‐carotene; DSM Nutrition Japan K.K., Tokyo, Japan) by oral administration daily from day 21 before expected calving date to parturition. Fourteen cows (control) did not receive β‐carotene supplementation. Blood samples were obtained on days 21, 14 and 7 before expected calving date and on days 1, 7, 14, 21 postpartum. When the plasma progesterone concentration exceeded 1 ng/ml by day 21 postpartum, luteal activity was assumed to have been initiated. The result showed that serum β‐carotene concentrations in the β‐carotene cows were higher than in the control cows during the experimental period (p < 0.01). The number of cows with the onset of luteal activity by day 21 postpartum was 9/12 in the β‐carotene cows and 4/14 in the control cows (p < 0.05). Retinol, certain metabolic parameters and metabolic hormones concentrations did not differ between β‐carotene and control cows. In addition, serum retinol concentration in β‐carotene cows without luteal activity was lower than in β‐carotene cows with luteal activity (p < 0.05), and serum gamma‐glutamyl transpeptidase concentration in β‐carotene cows with luteal activity (p < 0.05) and control cows without luteal activity (p < 0.01) was higher than in control cows with luteal activity. In conclusion, β‐carotene supply during the close‐up dry period may support the onset of luteal activity during early lactation in dairy cows.  相似文献   

5.
The current investigations were undertaken to study the mechanism of the adverse effect of phytoestrogens on the function of bovine granulosa (follicles >1< cm in diameter) and luteal cells from day 1–5, 6–10, 11–15, 16–19 of the oestrous cycle. The cells were incubated with genistein, daidzein or coumestrol (each at the dose of 1 × 10?6 m ). The viability and secretion of estradiol (E2), progesterone (P4) and oxytocin (OT) were measured after 72 h of incubation. Moreover, the expression of mRNA for neurophysin‐I/OT (NP‐I/OT; precursor of OT) and peptidyl‐glycine‐α‐amidating monooxygenase (PGA, an enzyme responsible for post‐translational OT synthesis) was determined after 8 h of treatment. None of the phytoestrogens used affected the viability of cells except for coumestrol. The increased secretion of E2 and P4 was only obtained by coumestrol (p < 0.05) from granulosa cells from follicles <1 cm in diameter and decreased from luteal cells on days 11–15 of the oestrous cycle, respectively. All three phytoestrogens stimulated (p < 0.05) OT secretion from granulosa and luteal cells in all stages of the oestrous cycle and the expression of NP‐I/OT mRNA in the both types of cells. The expression of mRNA for PGA was stimulated (p < 0.05) by daidzein and coumestrol in granulosa cells, and by genistein and coumestrol in luteal cells. In conclusion, our results demonstrate that these phytoestrogens can impair the ovary function in cattle by adversely affecting the synthesis of OT in follicles and in corpus luteum. However, their influence on the ovarian steroids secretion was less evident.  相似文献   

6.
In the first experiment, minced luteal tissues from cyclic ewes (n = 5) were incubated for 6 h. Media conditioned by these luteal tissue explants stimulated proliferation and migration of endothelial cells. In a second experiment, corpora lutea (CL) from superovulated ewes (n = 12) were dissociated (two ewes/dispersion) and separated into three fractions: a non-elutriated fraction containing a mixed population of luteal cells, a fraction enriched with small steroidogenic luteal cells, and a fraction containing primarily large steroidogenic luteal cells. Fractions (2 X 10(5) viable steroidogenic luteal cells per milliliter of medium) were incubated with LH in doses of 0, .1, 1, 10, and 100 ng/ml for 7 d. Conditioned media were collected on d 1, 3, 5, and 7 of incubation. Across all days of incubation, media from small luteal cells stimulated proliferation of endothelial cells. Media from large luteal cell incubations, however, secreted an endothelial mitogen only on d 7 of culture. Mixed luteal cell cultures secreted mitogenic activity on d 3, 5, and 7 of incubation, but not on d 1. Luteinizing hormone did not influence release of mitogenic activity by any luteal cell fraction. Across all days of incubation, media from large luteal cells contained more progesterone than those from small luteal cells (528 +/- 137 vs 48 +/- 16 ng/ml with no LH). Mixed (non-elutriated) and small luteal cells increased progesterone secretion in response to LH, and this response was maintained during long-term culture. Large luteal cells did not increase progesterone secretion in response to LH. Steroidogenic activity of all cell types decreased as incubation time progressed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

7.
Effect of polychlorinated biphenyles (PCBs) on viability and secretory function of luteal and granulosa cells from mature cows was studied. Luteal cells from corpora lutea of different developmental stages and granulosa cells from follicles of >1 cm< in diameter were used. Neither individual congeners (PCB-126, -77, -153) nor mixture of PCBs Aroclor Ar) 1248 at the dose of 1, 10 or 100 ng/ml affected the viability of cells (P>0.05) compared to control after 72 h of incubation. PCBs markedly increased (P<0.05-0.001) oxytocin (OT) secretion from granulosa cells. This effect was the most evident when granulosa cells from follicles <1 cm diameter was treated with PCB-77 which is assumed to stimulate both arylhydrocarbon receptor (AhR) and estradiol (E2) receptor. Even the lowest dose of this compound (1 ng/ml) outranged the effect produced by cortisol (10(-5)M) used as positive control. There was marked effect (P<0.05-0.001) of PCBs on luteal cells from days 6-15 of the estrous cycle. However, influence of PCBs on OT secretion from luteal cells on day 1-5 and 16-18 of the estrous cycle was less evident. Again, PCB-77 was the most efficient stimulator of OT secretion. While the lowest effect was found after treatment of cells with PCB-126 which has dioxin-like properties. It can be assumed that diverse effect of PCBs on female reproduction largely results from the influence of these compounds on ovarian OT secretion. Since both synthesis and secretion of ovarian OT in bovine do not markedly depend on estradiol, some alternative cellular pathways of PCBs on ovary function are suggested.  相似文献   

8.
In the ovary, the development of new capillaries from pre‐existing ones (angiogenesis) is a complex event regulated by numerous local factors. The dominant regulators of angiogenesis in ovarian follicles and corpora lutea are the vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), insulin‐like growth factor (IGF), angiopoietin (ANPT) and hypoxia‐inducible factor (HIF) family members. Antral follicles in our study were classified according to the oestradiol‐17‐beta (E2) content in follicular fluid (FF) and were divided into five classes (E2 < 0.5, 0.5–5, 5–20, 20–180 and >180 ng/ml FF). The corresponding sizes of follicles were 5–7, 8–10, 10–13, 12–14 and >14 mm, respectively. Follicle tissue was separated in theca interna (TI) and granulosa cells (GC). The corpora lutea (CL) in our study were assigned to the following stages: days 1–2, 3–4, 5–7, 8–12 13–16 and >18 of the oestrous cycle and months 1–2, 3–4, 6–7 and >8 of pregnancy. The dominant regulators were measured at mRNA and protein expression levels; mRNA was quantified by RT‐qPCR, hormone concentrations by RIA or EIA and their localization by immunohistochemistry. The highest expression for VEGF‐A, FGF‐2, IGF‐1 and IGF‐2, ANPT‐2/ANPT‐1 and HIF‐1‐alpha was found during final follicle maturation and in CL during the early luteal phase (days 1–4) followed by a lower plateau afterwards. The results suggest the importance of these factors for angiogenesis and maintenance of capillary structures for final follicle maturation, CL development and function.  相似文献   

9.
In 20 estrus cycles of 15 mares, Color Doppler ultrasound of corpora lutea and plasma progesterone concentration (P4) was analyzed on days 6, 10, 14, 16, and 18 after ovulation. Progesterone concentration was positively correlated with corpora lutea cross-sectional area (CSA), vascularized area (VA), and index of vascularization (IV = VA/CSA) (P < .0001). Cross-sectional area, VA, and IV in corpora lutea of mares with P4 < 1 ng/mL were significantly lower than in corpora lutea of mares with P4 > 1 ng/mL. Mares with CSA < 3,473 pixels, VA < 25.5 pixels, and IV < 7.6% were prone to express P4 < 1 ng/mL 25.4, 7.9, and 7.6 times more than mares with higher values, respectively. Corpus luteums analyzed parameters differed significantly between last cycles (LCs) of the breeding season and previous cycles until day 14 after ovulation (P < .05). No significant differences were found in P4 between LCs and previous ones.  相似文献   

10.
To evaluate the response of luteal cells to in vitro stimulation with luteinizing hormone (LH) or dibutyryl cyclic adenosine monophosphate (dbcAMP) and determine the secretion of progesterone by the fetoplacental unit, the corpora lutea were removed surgically in 10 cows (luteectomy) at 250 days (5 cows) or 270 days (5 cows) of gestation. During surgery, but before luteectomy, catheters were placed in the middle uterine artery and vein, carotid artery, and jugular vein. Blood samples were collected from all catheters just before luteectomy and at 8-hour intervals after luteectomy for 72 hours or until calving, whichever occurred first. Luteal tissue was prepared as a dispersed cell preparation and incubated with 0, 0.1, 1.0, 10, or 100 ng of LH/ml of medium or was incubated with 0, 0.5, or 2 mM dbcAMP. Synthesis of progesterone in response to LH by dispersed cells prepared from corpora lutea at 270 days was less (P less than 0.01; analysis of variance) than that by similar preparations at 250 days because a dose-response relationship was not observed for incubations of luteal tissue with LH at 270 days of gestation. Progesterone synthesis in response to the addition of dbcAMP also was less (P less than 0.01) at 270 than at 250 days of gestation. This difference in responsiveness to LH and dbcAMP between the 2 stages of gestation was not reflected by a significant difference between stages of gestation in systemic concentrations of progesterone before luteectomy.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
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   

12.
Experiments were conducted to determine the effect of additional gonadotropic support on induced corpora lutea of anestrous ewes. In one series of experiments, ewes were superovulated and half the ewes received an i.v. injection of 500 IU human chorionic gonadotropin (hCG) on day 5 after ovulation. Corpora lutea were collected from both groups on day 10 after ovulation. Dissociated corpora lutea collected from ewes which received additional hCG contained proportionately more large luteal cells than did those from control ewes (P<.05). In neither cell type was content of receptors for luteinizing hormone (LH) or secretion of progesterone in response to LH affected by an additional injection of hCG. Large cells from anestrous ewes produced more progesterone in response to LH (P<.05) than did large cells from similarly treated ewes during the breeding season. Small cells collected during either season responded similarly to LH. In another series of experiments, anestrous ewes were induced to ovulate and were exposed to fertile rams. Half the ewes received an i.v. injection of 500 IU hCG on day 5 after ovulation. Serum content of progesterone was higher on day 10 in ewes which received hCG 5 days earlier than in control ewes, although progesterone levels declined to generally nondetectable levels in nonpregnant ewes of both groups by day 16. Pregnancy rates in the two groups were not different. We concluded that additional gonadotropic support affects the morphology and function of corpora lutea from anestrous ewes and may be useful for enhancing fertility during the nonbreeding season.  相似文献   

13.
This study was designed to determine whether leptin modulates growth hormone (GH)- and insulin like growth factor-I (IGF-I)-stimulated progesterone (P4) production by corpora lutea (CL). Luteal cells were recovered from early developing (ELP) and mature (MLP) corpora lutea and cultured in defined medium with various combinations of GH, IGF-I, and leptin (0-200 ng/ml). P4 concentrations in the media were determined after 48 h of culture. During the early luteal phase, leptin at all used doses had no effect on basal P4 secretion, but it did suppress caspase-3 activity. When added in combination with GH, it had no effect on either GH-stimulated P4 secretion or apoptosis. Concomitant treatment with IGF-I and leptin decreased P4 secretion and parallelly increased the apoptosis rate. In mature corpora lutea of full secreting capacity, leptin at all doses had no effect on basal and GH-stimulated P4 secretion and caspase-3 activity. Only at the highest dose (200 ng/ml) when leptin was added with IGF-I did P4 secretion decrease with no effect on the caspase-3 activity. We conclude that the role of leptin is to restrict the stage of CL formation. During this luteal phase, leptin acts as an antiapoptotic factor and, at the same time, reverses antiapoptotic action of IGF-I, thereby protecting cells from excessive apoptosis and supporting retention of appropriate cell numbers, which is necessary for maintenance of homeostasis in developing CL.  相似文献   

14.
Abstract

AIM: To compare the efficacy of oxytocin given once daily, either I/V or I/M, on Days 7–14 post-ovulation, on the expression of oestrus in mares through to 65 days post-ovulation.

METHODS: Eighteen mares of various breeds that were displaying normal oestrous cycles were randomly assigned to one of three treatment groups on the day of ovulation (Day 0), detected using transrectal ultrasonography. Mares in the control group (n = 6) were given 1 mL saline I/V; mares in the I/V and I/M groups (n = 6 per group) were injected with 10 IU oxytocin I/V and I/M, respectively. All treatments were given once daily on Days 7–14. Mares were teased by a stallion three times per week, up to 65 days post-ovulation, to detect oestrous or dioestrous behaviour. Ovarian follicular and luteal activity were monitored using transrectal ultrasonography three times weekly, and daily when a follicle >30 mm diameter was present until ovulation. Blood samples were collected weekly for analysis of concentrations of progesterone in serum. Prolonged dioestrus was defined as a period of >30 days of dioestrous behaviour after Day 0, confirmed by detection of corpora lutea and concentrations of progesterone in serum >4 nmol/L.

RESULTS: Overall, 8/18 (44%) mares showed prolonged dioestrus. These included 2/6 (33%) mares in the control group, compared with 5/6 (83%) and 1/6 (16%) mares in the I/V and I/M groups, respectively (p = 0.11). The median duration of the first dioestrus was longer for the I/V group (64 (min 16, max 66) days) compared with the control group (18 (min 12, max 64) days) (p = 0.05), but was not different between the control group and the I/M group (16 (min 13, max 65) days) (p = 0.57). For all mares there was strong agreement between teasing behaviours, ultrasonographic assessment of ovarian activity, and concentration of progesterone in serum.

CONCLUSIONS AND CLINICAL RELEVANCE: This study found that low doses of oxytocin did not increase the proportion of mares with prolonged dioestrus, compared with controls, although I/V oxytocin did increase the median duration of dioestrus. The results must be interpreted with some caution as group numbers were small, and a variety of breeds were used. Further investigation of oxytocin given I/V may be warranted as a potential method of oestrus suppression in mares exhibiting oestrous cycles that is low cost, safe and well-tolerated, and potentially reversible with prostaglandin.  相似文献   

15.
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16.
OBJECTIVE: To determine whether IM administration of exogenous oxytocin twice daily on days 7 to 14 after ovulation blocks luteolysis and causes prolonged function of corpora lutea (CL) in mares. DESIGN: Prospective study. ANIMALS: 12 mares. PROCEDURES: Beginning on the day of ovulation (day 0), jugular blood samples were collected every other day until day 40 for determination of progesterone concentration. On day 7, mares (n = 6/group) were treated with saline (0.9% NaCl) solution (control group) or oxytocin. Beginning on day 7, control mares received 3 mL of sterile saline solution every 12 hours, IM, and oxytocin-treated mares received 60 units of oxytocin every 12 hours, IM, through day 14. Mares were considered to have prolonged CL function if progesterone concentration remained > 1.0 ng/mL continuously through day 30. RESULTS: The proportion of mares with prolonged CL function was significantly higher in the oxytocin-treated group (6/6), compared with the control group (0/6). All control mares underwent luteolysis by day 16, at which time their progesterone concentrations were < 1.0 ng/mL. In contrast, all 6 oxytocin-treated mares maintained progesterone concentrations > 1.0 ng/mL continuously through day 30. CONCLUSIONS AND CLINICAL RELEVANCE: IM administration of 60 units of oxytocin twice daily on days 7 to 14 after ovulation was an efficacious method of inhibiting luteolysis and extending CL function in mares. Disrupting luteolysis by administering exogenous oxytocin during diestrus appears to be a plausible and practical method of long-term suppression of estrus in mares.  相似文献   

17.
Polychlorinated biphenyls (PCBs) due to their lipophilic properties can be easily accumulated in animal and human body and elicit diverse effects causing impairment of reproductive processes. Since these compounds were not be able to affect directly the luteal steroidogenesis, the aim of the present study was to verify hypothesis that PCBs can impair the effect of LH on the secretory function of luteal cells. Bovine luteal cells from different stages of the oestrous cycle (days 1-5, 6-10, 11-15 and 16-18) were exposed for 72h to various congeners of PCBs (PCB 126, PCB 77 and PCB 153) at the doses of 1, 10 or 100 ng/ml, in the presence or absence of LH (100 ng/ml), to determine the possible effect of these compounds on progesterone (P4) and ovarian oxytocin (OT) secretion. Only PCB 77 on days 1-5 and 16-18 increased P4 secretion. All PCBs decreased LH-simulated secretion of P4 from luteal cells obtained from all days of luteal phase. Dioxin-like congener (PCB 126) inhibited (P<0.05) the most evidently LH effect on P4 secretion. All congeners, except the lower doses of PCB 126, increased (P<0.05) OT secretion. They can also increase LH-stimulated secretion of OT, but the effect was dependent on the congener used and on the phase of oestrous cycle. On days 1-5 and 10-15, PCB 126 diminished LH-stimulated effect on OT secretion from luteal cells. PCB 77 (mimickig both dioxin and estradiol effect) in the higher doses, amplified effect of LH-stimulated OT secretion, while on all other days it diminished LH influence. PCB 153, which has estrogen-like properties, amplified LH effect on OT secretion during all studied days of the cycle. We conclude that PCBs (supposedly via estrogen and arylhydrocarbon - AhR receptor) may directly affect LH-stimulated function of CL. This does not appear to be a direct adverse effect on luteal steroidogenesis, but rather indirect on OT secretion from or within CL.  相似文献   

18.
Seven hundred and six bovine corpora lutea in various luteal stages were examined morphologically and endocrinologically to discover whether there is a relationship between the presence of a central cavity in the corpus luteum and infertility in cows. A central cavity was found in 42.1 per cent (80/190) of developing corpora lutea, 33.7 per cent (126/374) of fully developed corpora lutea, 11.1 per cent (7/63) of corpora lutea in regression and in 5.1 per cent (4/79) of corpora lutea in pregnancy. There was no significant difference between the rates of appearance of midcycle follicles in corpora lutea either with or without a central cavity. The proportion of luteal cell type 1 was higher in fully developed corpora lutea with a central cavity than without, but the reverse was found with luteal cell type 2. In fully developed corpora lutea the concentration of progesterone in the luteal tissue was significantly higher in corpora lutea with a central cavity. These results suggest that there are some differences in luteal function between corpora lutea with and without a central cavity, but that the presence of a central cavity in a corpus luteum cannot be described as a pathological condition.  相似文献   

19.
The current study aimed to compare luteal function, as measured by corpora lutea dynamics and progesterone secretion, in 10 sows with obesity/leptin resistance genotype (Iberian pig) and 10 females of lean commercial crosses (Large White × Landrace). In all the animals, the oestrous cycle was synchronized with progestagens, and ovulation was induced by exogenous gonadotrophins. Thereafter, number and size of follicles and plasma oestradiol concentration were determined at oestrus detection, and number and size of corpora lutea and progesterone concentration were evaluated from Day 4 to 12 of the cycle. There were no differences between genotypes in follicle population and oestradiol concentration, and ovulation rate (15.2±1.3 in Iberian vs 12.7±1.8 in LWxL sows); however, there was a higher percentage of Iberian than control sows showing luteal cysts (66.7% vs 30%, respectively; p<0.05). In both breeds, both total luteal area and plasma progesterone concentration grew linearly from Day 4 to 8 (p<0.01) and remained more stable between Days 8 and 12, without significant differences between genotypes. In conclusion, current study supports that ovulatory processes and luteal functionality are not the main limiting factors for prolificacy in a pig model of leptin resistance and obesity.  相似文献   

20.
The aim of the present study was to examine the plasma concentrations of progesterone, oestradiol-17beta and cortisol in the cows with cystic follicle and to examine its relationship with the ovulatory response to gonadotropin-releasing hormone (GnRH). Eighty-five post-partum Holstein-Friesian cows with cystic follicles regardless of the presence of corpus luteum were studied. Follicular size, presence of corpus luteum and occurrence of ovulation were checked by palpation per rectum. Blood collection and palpation per rectum were conducted on days 0, 7 and 14. Gonadotropin-releasing hormone was administered at day 7. Plasma concentrations of progesterone, oestradiol-17beta and cortisol were determined. Progesterone concentrations of <3.2, 3.2-4.8 and >4.8 nmol/l were defined as low, intermediate and high, respectively. Sixty-three (74.1%) of 85 cows showed low (<3.2 nmol/l =1 ng/ml) progesterone concentrations on day 0. Only 40 (47.1%) of them showed low-low pattern of progesterone at days 0 and 7. In 27 (31.8%) of them, progesterone concentration had increased by day 14. Of 22 cows having high progesterone concentration (>/=4.8 nmol/l) on day 0, corpus luteum was not detected in 18 cows (21.2%). Only in 10 cows, cystic follicle disappeared after GnRH administration. However, only one of 27 cows in which progesterone pattern was low-low-high at days 0, 7 and 14 experienced ovulation of the cystic follicle. Significantly lower oestradiol-17beta concentration was found on day 7 in cows showing a low-low-low pattern than a low-low-high pattern of progesterone (43.0 +/- 4.6 vs 55.8 +/- 2.8 pmol/l, p < 0.05). There was no significant difference in cortisol concentration on any days (days 0, 7 and 14) between cows showing a low-low-low and low-low-high pattern of progesterone. These results suggest that approximately one-fifth of cows diagnosed to have ovarian cysts possess luteal cysts and that a high oestradiol-17beta concentration at the time of GnRH administration is involved in the subsequent ovulation of the follicle, although ovulated follicle may not be cystic.  相似文献   

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