首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 531 毫秒
1.
The hypothesis of the present study is that active immunization of cows against inhibin would neutralize endogenous inhibin, increase circulating levels of follicle stimulating hormone, and subsequently affect follicular dynamics and the ovulation rate during the estrous cycle. Thirteen cows were immunized against inhibin alpha-subunit and, 6 cows were immunized with a placebo. Both groups were given 4 booster immunizations 7, 14, 21, and 34 weeks after the primary injection. Ovaries were examined daily after the 2nd, 3rd, and 4th booster immunizations by transrectal ultrasonography for 25 days. After the 4th booster immunization, blood samples were collected daily for one complete estrous cycle to measure FSH and LH. The results showed that the immunized cows generated antibodies against inhibin, and that they had higher FSH levels compared with the controls. The number of follicular waves during the estrous cycle was higher in the immunized cows (3 or 4 waves) than in the controls (2 or 3 waves). Moreover, the immunized cows had a greater number of follicles during the estrous cycle compared with the control cows. The maximum number of follicles was 14.8 +/- 1.7 vs 5.4 +/- 0.2 in inhibin-immunized and control cows, respectively, during the first follicular wave and 13.9 +/- 1.9 vs 5.6 +/- 0.7, respectively, during the ovulatory wave. Multiple ovulations were increased in the immunized cows. However, the ovulation rate varied greatly in the immunized animals. In conclusion, immunization against inhibin increased FSH secretions during the estrous cycle in the cows. Moreover, the immunized cows had a greater number of follicular waves during the estrous cycle and a greater number of follicles, and this could be used as a potential source of oocytes for use in IVF/embryo transfer programs.  相似文献   

2.
To test whether inhibin A assays can be used for the prediction of yields in embryo programmes in goats, 50 does were treated with 45 mg FGA sponges (Chronogest) for 16 days plus a single dose of 100 microg i.m. cloprostenol on Day 14, just before the start of administration of eight doses of 1.25 ml of Ovagen twice daily for 4 days. At first FSH injection, the number and size of all follicles > or =2 mm was assessed by transrectal ultrasound and plasma inhibin A levels were measured by specific dimeric assay. There was a positive correlation between number of follicles > or =6 mm (8.8 +/- 0.5) and inhibin A levels at first FSH dose (193.2 +/- 14.5 pg/ml, P<0.05). The mean number of corpora lutea on Day 7 after sponge removal was related to the total number of follicles with a diameter of 2-6 mm at the onset of the FSH treatment (15.3 +/- 0.7, P<0.05). The total number of embryos recovered was related to the number of follicles with 4-6 mm in size (6.2 +/- 0.5, P<0.05) and to the inhibin A levels at first FSH dose (P<0.05). These results suggest that follicles > or =4 mm are the source of inhibin prior to FSH stimulation and are the main source of oocytes resulting in the number of viable embryos recovered after a superovulatory treatment. Hence, the response to superovulatory treatments in goats in terms of the number of embryos can be predicted from either the population of follicles determined by ultrasound or the plasma inhibin A levels at start of the superovulatory FSH treatment.  相似文献   

3.
The effects of exogenous equine somatotropin (eST) administration on ovarian activity and plasma hormone levels were evaluated on horse and pony mares. The objectives of this study were to determine the effects of eST on follicular development and circulating concentrations of leutinizing hormone (LH), estradiol, progesterone, and insulin-like growth factor I (IGF-I) in cyclic horse and pony mares. Sixteen mares received daily injections (i.m.) of eST at a concentration of 25 micrograms/kg body weight on either Days 6 through 12 (Treatment A) or 13 through 19 (Treatment B) postovulation. In addition, contemporary mares were similarly given the carrier vehicle and served as controls (Treatments C and D). Blood samples were collected at 24-hr intervals and ultrasonographic evaluations were performed on the ovaries of each mare at 48-hr intervals beginning on the first day of treatment and ending either on the day of ovulation or 5 d postovulation. Circulating levels of insulin-like growth factor-I (IGF-I) were increased in treated mares by Day 3 post-treatment (P < 0.05). Also, mares in Treatment B exhibited a decrease in plasma estradiol concentrations (P < 0.05) when compared with control mares on Days 1 through 5 postovulation of the post-treated estrous cycle. In addition, circulating leutinizing hormone levels were different for mares in Treatment A compared with controls on Days--8 through--1 pre-ovulation (P < 0.05). All follicles present on the ovaries of each mare were measured and placed into one of five categories based on their diameter. Neither the mean number of follicles per size category > or = 8 mm in diameter nor the mean follicular diameter within each size category differed among treatment and control mares. However, eST treatment significantly increased the number of follicles < or = 7 mm on the ovaries of mares treated early in the estrous cycle when compared with control mares on Days 3 and 7 post-treatment and at the onset of standing estrus.  相似文献   

4.
A heterologous radioimmunoassay developed to measure inhibin in rat plasma was validated and used to characterize changes in peripheral concentrations of immunoreactive inhibin (ir-inhibin) in relation to follicle stimulating hormone (FSH) concentrations during the estrous cycle of mares. The primary antiserum used in the assay was developed against a synthetic porcine inhibin -subunit [(1-26)-Gly-Tyr] fragment. The same synthetic peptide was used for preparation of standards and tracer. Slopes of the dose-response curves for pooled estrus and diestrus mare plasma and equine follicular fluid were similar to the slopes for the porcine inhibin -subunit standard curve and porcine follicular fluid dose-response curve. Twelve mares were bled once daily beginning when diameter of the largest follicle reached ≤25 mm and continuing until 3 days after the end of an interovulatory interval (ovulation=Day 0). Each of the 12 interovulatory intervals were normalized to the mean length of the interovulatory interval (22.2 days; range, 19 to 26). There was an effect of day for concentrations of ir-inhibin (P<0.001) and FSH (P<0.006). Significant mean changes were as follows: 1) ir-inhibin decreased between Days 0 and 1, whereas FSH increased between Days 0 and 5; and 2) ir-inhibin increased between Days 7 and 12, whereas FSH decreased between Days 11 and 14. Mean concentrations of ir-inhibin and FSH were negatively correlated (r=-0.548; P<0.002). In conclusion, mean peripheral concentrations of ir-inhibin and FSH were inversely related during the estrous cycle of mares.  相似文献   

5.
To elucidate the effects of ultrasound-guided transvaginal follicular aspiration, plasma concentrations of FSH, LH, inhibin, estradiol-17beta and progesterone, and folliculogenesis were examined in Holstein cows. Four clinically healthy cows with regular estrous cycles were scanned by ultrasound per rectum once a week for 9 weeks before the commencement of follicular aspiration. All visible follicles were divided into 3 categories based on their sizes (2 < or = small < 5 mm; 5 < or = medium < 10 mm, large > or = 10 mm). The follicular aspiration was started at random during the estrous cycle and conducted under epidural anesthesia induced with 5 ml of 2% lidocaine once a week for 6 weeks. The average number of total visible follicles > or = 2 mm in diameter at 7 days after aspiration (21.7 +/- 7.4, n = 24) was similar to that before starting aspiration (26.7 +/- 10.5, n = 36). Plasma inhibin and estradiol-17beta declined and fell to a trough on 1.5 days and returned to pre-aspiration values by 5 days after aspiration. Plasma concentrations of FSH increased and reached peak levels between 1 and 1.5 days after aspirations. Plasma concentrations of LH also increased and reached peak levels between 0.5 and 1.5 days after aspirations. Both plasma FSH and LH had returned to pre-aspiration levels by 5 days after aspirations. Plasma concentrations of progesterone did not change with the follicular aspiration. These results demonstrate that follicular aspiration decreases plasma concentrations of inhibin and estradiol-17beta, which in turn leads to a rise in plasma concentrations of FSH and LH. It is suggested that marked increases in plasma concentrations of FSH and LH after the aspiration stimulate the development and maturation of a new cohort of follicles within one week in cows.  相似文献   

6.
The effects of unilateral and bilateral ovariectomy and passive immunization against inhibin on follicle-stimulating hormone (FSH) secretions and follicular development in the guinea pig were investigated. Bilateral ovariectomy decreased plasma immunoreactive (ir-) inhibin rapidly and increased plasma FSH significantly. Unilateral ovariectomy decreased plasma ir-inhibin and increased plasma FSH temporarily, and doubled the number of ova released from the remaining ovary at the subsequent ovulation in guinea pigs. Injection of 1.0 ml inhibin antiserum significantly increased concentrations of plasma FSH at 6 hr onwards and the number of small follicles (100-200 microm in diameter) at 48 hr after the injection in guinea pigs bearing progesterone-containing implants. In vitro bioassay showed that inhibin antiserum could neutralize the suppression of ovarian homogenate on FSH secretion from cultured rat anterior pituitary cells. These results confirm the evidence that the ovary is the main source of inhibin secretion and both in vitro bioassay and passive immunization against inhibin show that the inhibin is a major regulator in the follicular development through FSH secretion in guinea pigs.  相似文献   

7.
We reported previously that passive immunization against inhibin enhances follicular growth and increases the ovulation rate. However, the ovulation rate was not comparable to the number of follicles. Therefore, the aim of this study was to attempt to increase the ovulation rate by increasing the interval between inhibin immunization and PGF2alpha injection. Five miniature Shiba goats were treated with 10 ml inhibin antiserum (inhibin-AS) developed against [Tyro30]-inhibin alpha (1-30). A control group (n=5) was treated with normal goat serum. All animals were injected intramuscularly with 125 microg PGF2alpha 72 h after treatment to induce estrus and ovulation. Blood samples were collected for hormonal assay and the ovulation rate was determined by laparotomy. In contrast to the control group, there was a significant increase in plasma concentrations of FSH in the immunized group. After luteolysis, plasma concentrations of estradiol-17beta increased markedly to a preovulatory peak about 2 folds higher (P<0.01) than that of controls. In addition, the ovulation rate was greater in the immunized group (14.4 +/- 2.2) than in the control group (2.2 +/- 0.6), and the mean number of follicles > or = 4 mm in diameter was 10.0 +/- 0.8 in the inhibin-AS group compared with 2.4 +/- 0.3 in control group. The present results demonstrate that immunoneutralization of endogenous inhibin increased FSH secretions in miniature shiba goats. The increased FSH secretion enhanced follicular growth and increased the ovulation rate. Additionally, increasing the interval between inhibin-AS and PGF2alpha injections (to 72 h) resulted in a greater ovulation rate compared with the previous protocol (48 h). Therefore, inhibin-AS treatment proved to be an effective alternative to exogenous gonadotropin methods for induction of superovulation in goats.  相似文献   

8.
OBJECTIVE: To determine whether concentrations of dimeric inhibin (CaCA) are greater in plasma and tumor fluid from mares with granulosa-theca cell tumors (GTCT), compared with concentrations in plasma and equine follicular fluid (eFF) from control mares. ANIMALS: 6 mares with GTCT and 12 clinically normal mares. PROCEDURE: The alphabetaA immunoradiometric assay used 2 antibodies, one against each subunit of inhibin (alpha and betaA subunits). Tumor tissue, tumor fluid, and a single blood sample were collected at the time of surgical removal of the GTCT. A single blood sample was collected from 7 control mares during various stages of the estrous cycle. Five other control mares were ovariectomized when their ovaries contained growing follicles of 25 to 35 mm in diameter. A blood sample and eFF from the largest follicle were collected at the time of ovariectomy. RESULTS: Mares with GTCT had significantly greater plasma concentrations of betabetaA (mean +/- SEM, 0.86 +/- 0.53 ng of recombinant human-alphabetaA/ml), compared with control mares (0.14+/-0.02 ng/ml). Concentrations of alphabetaA in tumor fluid and eFF were similar. Concentrations of alphabetaA were significantly lower after ovariectomy. CONCLUSIONS AND CLINICAL RELEVANCE: Dimeric inhibin concentration was higher in plasma from mares with GTCT than in plasma from control mares. Increased granulosa cell mass and loss of mechanisms regulating alphabetaA release in mares with GTCT likely accounted for the increase in plasma concentrations. Measurement of alphabetaA concentrations may be useful for identifying mares with GTCT.  相似文献   

9.
In the present study, two experiments were conducted to induce superovulation in goats using passive and active immunization against inhibin. In the first experiment, two groups of goats were given an intravenous injection of either 10 ml normal goat serum (control; n=6) or inhibin antiserum developed against [Tyro30]-inhibin alpha (1-30) (passively immunized; n=6) 48 h before treatment with PGF2alpha. In the second experiment, two groups of goats were immunized with inhibin vaccine (actively immunized; n=5) or Freund's adjuvant (control; n=5) followed by three booster immunizations at 4 week intervals. Blood samples were collected for determination of FSH, LH, estradiol-17beta, and progesterone. Ultrasonography was used to determine ovarian activity at PGF2alpha injection and ovulation rate one week after estrus. In both experiments, there was a significant increase in plasma FSH concentration compared with the controls. However, the pattern of the FSH levels was different between the passively and actively immunized goats. The numbers of follicles in passively and actively immunized goats (22.4 +/- 2.3 and 18.6 +/- 2.1, respectively) were significantly greater than those in the controls (2.6 +/- 0.4 and 2.3 +/- 0.4, respectively). In addition, the ovulation rate was greater in the immunized animals compared with the controls. Therefore, either passive or active immunization against inhibin could be used to induce superovulation in goats.  相似文献   

10.
将90只大鼠随机分为5组,分别注射10μg.100μL-1 pcISI(T1)、50μg.100μL-1 pcISI(T2)、100μg.100μL-1(T3)pcISI、100μg空载体pcMV-S(V)和100μL生理盐水(S),以探讨在不使用免疫佐剂的情况下,不同剂量的双拷贝抑制素pcISI基因免疫对大鼠卵泡发育、产仔和生殖激素的影响。结果表明,加强免疫能提高抗体P/N值,加强免疫后各剂量组平均抗体P/N值大于2,T3组抗体P/N值显著高于T1和T2组(P<0.05)。T3组成熟卵泡数显著高于对照组(P<0.05),且抗体阳性鼠成熟卵泡数比阴性鼠多12.45个(P<0.05)。除了T1组外,其他2个剂量组产仔数和胎盘数均高于对照组(P<0.05)。抗体阳性鼠胎盘数比阴性鼠多5.09个(P<0.05),产仔数比阴性鼠多5.39个(P<0.05)。抑制素pcISI基因免疫大鼠后促卵泡素(FSH)、雌二醇(E2)和孕酮(P4)含量均高于对照组,T3组的FSH含量与对照组差异显著(P<0.05),T3组的E2含量与对照组差异极显著(P<0.01),各剂量组P4含量与对照组差异均不显著(P>0.05)。这些结果说明,在没有免疫佐剂的前提下,双拷贝抑制素pcISI基因免疫可产生抗体,促进FSH分泌和卵泡发育,增加产仔数。本试验条件下100μg.100μL-1是最佳免疫剂量。  相似文献   

11.
OBJECTIVE: To evaluate gonadotropin secretion and ovarian function after administration of deslorelin acetate to induce ovulation in mares. DESIGN: Randomized controlled trial. ANIMALS: 16 healthy mares with normal estrous cycles. PROCEDURE: 8 control mares were allowed to ovulate spontaneously, whereas 8 study mares received deslorelin to induce ovulation when an ovarian follicle > 35 mm in diameter was detected. Follicle development and serum concentrations of gonadotropins were monitored daily during 1 estrous cycle. Pituitary responsiveness to administration of gonadotropin-releasing hormone (GnRH) was evaluated 10 days after initial ovulation. RESULTS: Interovulatory intervals of mares treated with deslorelin (mean +/- SD, 25.6 +/- 2.6 days) were longer than those of control mares (22.9 +/- 1.8 days). Diameter of the largest follicle was significantly smaller during 2 days of the diestrous period after ovulation in deslorelin-treated mares than in control mares. Concentrations of follicle-stimulating hormone (FSH) were lower in deslorelin-treated mares on days 5 through 14 than in control mares. Concentrations of luteinizing hormone were not different between groups during most of the cycle. Gonadotropin release in response to administration of GnRH was lower in mares treated with deslorelin acetate than in control mares. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of deslorelin was associated with reduction in circulating concentrations of FSH and gonadotropin response to administration of GnRH during the estrous cycle. Low concentration of FSH in treated mares may lead to delayed follicular development and an increased interovulatory interval.  相似文献   

12.
The well-documented phenomenon of reduced conception rate in dairy cows during the hot season involves impaired functioning of the ovarian follicles and their enclosed oocytes. Three experiments were performed to examine the administration of low doses of follicle-stimulating hormone (FSH) to induce turnover of follicles that are damaged upon summer thermal stress and to examine whether this FSH administration has beneficial effects on preovulatory follicles. In experiment 1, synchronized heifers were treated with 100 mg of Folltropin-V (n = 7) or 4.4 mg of Ovagen (n = 6) on day 3 of the estrous cycle. Treatment with both FSH sources resulted in greater (P < 0.05) numbers of follicles than in control animals (n = 12) on day 6 of the estrous cycle, indicating that low doses of FSH can increase the number of emerging follicles in a follicular wave. In experiment 2, milking cows were assigned to a control group (n = 4) or treated with 2.2 mg (FSH-2.2; n = 6) or 4.4 mg (FSH-4.4; n = 5) Ovagen. Follicle-stimulating hormone was administrated on day 3 or 4 and day 10 or 11 of the estrous cycle, coinciding with emergence of the first and second follicular waves, respectively. The number of follicles emerging during the first wave tended to be higher (P < 0.1) in FSH-4.4-treated cows than in controls. The second-wave dominant follicles emerged 2 d later in the treated cows and were smaller in diameter (P < 0.05) than controls, 2 d before aspiration. Despite being younger, the preovulatory follicles of FSH-4.4 cows expressed a steroidogenic capacity that was similar to controls with a tendency toward greater insulin concentrations (P < 0.09). In experiment 3, milking cows were assigned to a control group (n = 6) or treated with 4.4 mg Ovagen (FSH-4.4; n = 6). Follicle-stimulating hormone was administrated on day 3 and day 12 or 13 of the estrous cycle. The number of emerging follicles was higher (P < 0.05) in the treated vs control cows. However, the features of the preovulatory follicle developed in the subsequent cycle did not differ between groups. In summary, low doses of FSH can efficiently induce follicular turnover accompanied by a modest effect on the preovulatory follicle of the treated cycle. It appears that the administration of low doses of FSH, precisely timed to synchronize with the emergence of follicular waves, might have a beneficial effect on the preovulatory follicle and its enclosed oocyte.  相似文献   

13.
Inhibins are gonadal glycoprotein hormones selectively and potently inhibiting follicle‐stimulating hormone (FSH) secretion from the pituitary gland. Inhibins are produced mainly by the ovary and are purified from follicular fluid. Inhibins were shown to be produced in two forms through dimeric assembly of an α‐subunit and one of two closely related β‐subunits to form inhibin A (α‐βA) and inhibin B (α‐βB). Although inhibin subunits are expressed in various tissues, the gonads are the major source of circulating inhibins. While inhibins may act as a paracrine or autocrine factor in some tissues, their best understood roles are as endocrine regulators of pituitary FSH. In this review we focus our attention on more recent developments in inhibin research. We describe patterns of inhibin A and B secretion during the estrous cycle. We also review the immunization against inhibin α subunit as a practical method for superovulation. Superovulation has been induced successfully by passive or active immunization against the inhibin α‐subunit in several species such as mice, rats, hamsters, guinea pigs, cows, mares, ewes and goats. Furthermore, several studies have shown that oocytes superovulated with immunization against inhibin α‐subunit have the ability to develop normally, suggesting that inhibin immunization could be used as a practical method for superovulation in a wide range of animal species.  相似文献   

14.
The objective was to determine if the endocrine status of the animal dictates the responsiveness of gonadotrophs to estradiol, activin, inhibin and follistatin; hormones implicated in the differential release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Bovine pituitaries were obtained at 13 (n=8), 30 (n=24) and 66 (n=8) h after the onset of estrus, corresponding to before, during and the end of the first FSH increase of the estrous cycle which follows the pre-ovulatory gonadotropin surge in heifers. Heifers slaughtered at 30 h received no treatment, or were treated with progesterone with or without estradiol before slaughter to suppress the first transient FSH increase. Secretion of FSH from cultured pituitary cells, reflecting the prior in vivo status, was greater (P<0.01) at 30 h than 13 or 66 h, whereas, LH secretion was less (P<0.01) at 13 h compared with 30 h. Treatment with exogenous steroids decreased (P<0.05) the pituitary gland's ability to subsequently secrete FSH and LH. Inhibin and, to a greater extent, estradiol decreased (P<0.01) mean FSH secretion but increased (P<0.05) mean LH secretion. These findings suggest that estradiol and inhibin both have the ability to differentially modulate basal gonadotropin secretion during the first FSH increase of the bovine estrous cycle. Differential regulation of LH and FSH is mediated via an alteration in gonadotropin biosynthesis and basal secretion. Furthermore, the secretory capability of cultured pituitary cells and basal gonadotropin secretion reflect the prior endocrine status of the animal from which pituitaries were obtained.  相似文献   

15.
Effects of testosterone propionate (TP) treatment on plasma concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) before and after an injection of gonadotropin releasing hormone (GnRH) were studied using ovariectomized cows and pony mares. An initial injection of GnRH (1 microgram/kg of body weight) was followed by either TP treatment or control injections for 10 (cows) or 11 (ponies) d. A second GnRH injection was administered 1 d after the last TP or oil injection. Concentrations of LH and FSH were determined in samples of plasma taken before and after each GnRH injection. Control injections did not alter the response to GnRH (area under curve) nor the pre-GnRH concentrations of LH and FSH in ovariectomized cows or ponies. Testosterone treatment increased (P less than .01) the FSH release in response to GnRH in ovariectomized mares by 4.9-fold; there was no effect in cows, even though average daily testosterone concentrations were 59% higher than in pony mares. Testosterone treatment reduced the LH release in response to GnRH by 26% in ovariectomized mares (P less than .05) and by 17% in ovariectomized cows (P approximately equal to .051). These results are consistent with a model that involves ovarian androgens in the regulation of FSH secretion in the estrous cycle of the mare, but do not support such a model in the cow.  相似文献   

16.
Fifty crossbred gilts immunized against bovine serum albumin (BSA) or androstenedione conjugated to BSA (AD) were used in three experiments. Primary immunizations were given at 120 d of age and boosters at 148 and 176 d. Gilts were moved to pens containing four to five animals each and exposed to boars beginning at 180 d of age. Immunization against AD did not affect age at puberty, percentage of gilts exhibiting estrus or duration of first estrous cycle. Over the three experiments, ovulation rate was 24% greater for AD-immunized gilts than for controls, and the number of corpora lutea was related positively (r = .82) to the log of the antibody titer. Number of ovulations decreased as interval from booster immunization to onset of estrus increased. During diestrus of the first estrous cycle, gilts immunized against AD had more follicles 5 to 10 mm in diameter, more total ovarian follicles and more total ovarian structures (corpora lutea plus follicles) than controls. Immunization against AD increased the frequency of LH pulses on d 16 but not on d 17 or 18, of the estrous cycle. However, average serum concentrations of LH, FSH and estradiol from 5 d before until 2 d after expected estrus were not different between treatment groups. Concentrations of AD in follicles 4 to 6 and greater than 7 mm in diameter were greater in gilts immunized against AD. Mean serum progesterone was higher on d 9 and 12 after mating in AD immunized gilts than in controls. Immunization against AD had no effect on maintenance of pregnancy or embryo survival rate.  相似文献   

17.
A GnRH antagonist (Acyline) was used to study the role of FSH in early development of a follicular wave in 61 mares. In Experiment 1, a single dose of 3 mg per mare, compared with 0 and 1 mg, suppressed both the FSH and follicle responses to exogenous GnRH. In Experiment 2, high concentrations of FSH were induced by two successive ablations of all follicles ≥ 6 mm on days 10 and 13 (day 0 = ovulation). A single treatment with Acyline resulted in significantly greater suppression of plasma concentrations of FSH than a single treatment with charcoal-extracted follicular fluid (source of inhibin) or oestradiol. Suppression of FSH was not significantly different between the group treated with Acyline alone and a group treated with a combination of Acyline, inhibin and oestradiol. In Experiment 3, all follicles were ablated on day 10 to induce an FSH surge and a new follicular wave. Acyline treatment on day 10 resulted in an immediate decrease in FSH, without a significant effect on day of emergence of a new wave or growth of follicles from 7 to 11 mm on days 11–13. Treatment on day 15, a day before expected follicle deviation and after the peak of the wave-stimulating FSH surge, resulted in an immediate decrease in FSH and cessation of follicle growth. Results indicated that growth of follicles for about 2 days after wave emergence was independent of FSH. In contrast, during the decline in the wave-stimulating FSH surge and before follicle deviation, growth of follicles was dependent on FSH.  相似文献   

18.
The aim of the current study was to clarify the physiological role of inhibin in controlling FSH secretion and follicular development during the early pregnancy in goats. Eight goats investigated sonographically on Days 19-21 (Day 0=day of mating) for pregnancy were assigned into control (n=3) and treated (n=5) groups. The ovaries of all animals were daily scanned with ultrasound for follicles 2mm or more in diameter from 1 day before to 5 days after treatment. On Day 25 postbreeding; animals received either 10 ml, of normal goat serum or antiserum against [Tyr (30)]-inhibin alpha (1-30). Jugular blood samples were collected every 6 h starting 24 h before and until 120 h after treatment. The plasma concentration of FSH increased at 6 h and remained at significantly high levels until 120 h in treated vs. control group. The plasma concentrations of estradiol showed a marked increased at 66 h, with peak levels at 120 h after treatment of antiserum. The basal concentrations of LH and the pattern of plasma concentrations of progesterone were not significantly different between the two groups. The number of medium size (3.5-5.0 mm) follicles increased considerably from Day 2, whereas small (3.5 mm or less) and large (5 mm or more) follicles increased noticeably from Day 3, as compared with pre-treatment and controls. These results clearly indicated that inhibin is a key hormone in regulation of follicular development through regulation of endogenous FSH secretion during early pregnancy in goats.  相似文献   

19.
The use of equine FSH (eFSH) for inducing follicular development and ovulation in transitional mares was evaluated. Twenty-seven mares, from 3 to 15 years of age, were examined during the months of August and September 2004, in Brazil. Ultrasound evaluations were performed during 2 weeks before the start of the experiment to confirm transitional characteristics (no follicles larger than 25 mm and no corpus luteum [CL] present). After this period, as the mares obtained a follicle of at least 25 mm, they were assigned to one of two groups: (1) control group, untreated; (2) treated with 12.5 mg eFSH, 2 times per day, until at least half of all follicles larger than 30 mm had reached 35 mm. Follicular activity of all mares was monitored. When most of the follicles from treated mares and a single follicle from control mares acquired a preovulatory size (≥35 mm), 2,500 IU human chorionic gonadotropin (hCG) was administered IV to induce ovulation. After hCG administration, the mares were inseminated with fresh semen every other day until ovulation. Ultrasound examinations continued until detection of the last ovulation, and embryo recovery was performed 7 to 8 days after ovulation. The mares of the treated group reached the first preovulatory follicle (4.1 ± 1.0 vs 14.9 ± 10.8 days) and ovulated before untreated mares (6.6 ± 1.2 vs 18.0 ± 11.1 days; P < .05). All mares were treated with prostaglandin F2α (PGF2α), on the day of embryo flushing. Three superovulated mares did not cycle immediately after PGF2α treatment, and consequently had a longer interovulatory interval (22.4 vs 10.9 days, P < 0.05). The mean period of treatment was 4.79 ± 1.07 days and 85.71% of mares had multiple ovulations. The number of ovulations (5.6 vs 1.0) and embryos (2.0 vs 0.7) per mare were higher (P < 0.05) for treated mares than control mares. In conclusion, treatment with eFSH was effective in hastening the onset of the breeding season, inducing multiple ovulations, and increasing embryo production in transitional mares. This is the first report showing the use of FSH treatment to recover embryos from the first cycle of the year.  相似文献   

20.
The aims of this study were to ascertain 1) whether fetal maturation could be induced precociously by maternal administration with adrenocorticotrophic hormone (ACTH) and 2) whether maturation could be achieved without significant risk to mare or fetus. Twenty-two mares received either 1 mg (low dose, LD, n = 6) or 4 or 5 mg (higher dose, HD, n = 16) synthetic Depot ACTH(1-24) at 300, 301 and 302 days gestation. Because, during the course of the study, ACTH appeared to have a greater influence on mares mated during the later part of the breeding season, the HD group were divided retrospectively into those mated before (HDE, n = 6), or after (HDL, n = 10), 1st July. All LD mares were mated before 1st July. Control injections were not performed but gestational data were compared retrospectively with 64 untreated, spontaneously foaling pony mares mated between May and October. Plasma progestagen and cortisol concentrations increased significantly (P<0.05) following ACTH administration in all groups, but progestagens were higher and cortisol elevated for longer in HD mares. ACTH stimulated mammary development and milk electrolyte changes in HD mares. Mean +/- s.e. gestation period (days) was significantly (P<0.01) shorter in HDL mares (318 +/- 1.8) compared with LD (335 +/- 3.7), HDE (340 +/- 4.3) and untreated mares mated after 1st July (327 +/- 1.3). All foals were mature except 2 HDL foals which were stillborn. HDL foals had a higher MCV and lower mean bodyweight, indicating they were delivered before full term. In conclusion, maternal ACTH administration appears to accelerate fetal maturation and delivery in pony mares given high doses and mated late in the breeding season. Further work is required to establish the optimal gestational age and dosage for maternal ACTH administration before clinical recommendations can be given for this therapy.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号