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1.
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2.
The object of this investigation was to study luteinizing hormone (LH) response to different doses of synthetic gonadotropin-releasing hormone (GnRH) in prepubertal gilts. Four crossbred prepubertal gilts, 128–134 days old and body weight 57–63 kg, were used in this study. Four doses, 0. 5, 25 and 125 μg, of GnRH were administered via a jugular vein catheter in a latin square design. Each treatment consisted of 3 injections at 90 min intervals. Frequent blood samples were taken during a period of 90 min before up to 90 min after treatment. Total LH responses were measured from post-treatment samples as the area under the curve above base level obtained from pre-treatment samples. A positive relationship between GnRH dose and LH release was obtained in all gilts, except for 1 treatment given to a gilt with high plasma level of oestradiol-17β on the day of treatment. This study has demonstrated the responsiveness of the pituitary gland by LH release to different doses of GnRH in 4.5-month-old prepubertal gilts.  相似文献   

3.
Clinical and endocrinological responses to administration of gonadotropin releasing hormone analog (LH-RH-A) during the lactation period and postweaning in the sow were investigated. Plasma LH concentrations in lactating sows rose immediately after administration of LH-RH-A. However, in postweaning sows the increase of LH level was more slowly. Three of 5 postweaning sows came into estrus and ovulated after LH-RH-A treatment. One sow exhibited a distinct LH response, but her ovaries remained quiescent. The remaining one with feeble estrus for a short period became cystic ovaries. Thus, LH response to GnRH in the sow seems to be higher during early lactation than at 2 days postweaning.  相似文献   

4.
Equine chorionic gonadotropin (eCG), which consists of highly glycosylated alpha- and beta-subunits, is a unique member of the gonadotropin family because it elicits response characteristics of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in species other than the horse. In this study, recombinant tethered-eCG as well as its deglycosylated mutants were produced to determine if alpha- and beta- subunits can be synthesized as a single polypeptide chain (tethered-eCG) and display biological activity. We found that tethered-eCG (T- betaalpha) had both LH- and FSH-like activities comparable to dimeric eCG. Luteinizing hormone-like activity of tethered-eCGs deglycosylated at Asn(56) (T-betaalpha56) was decreased. In contrast, LH-like activity of eCG without O-glycosylated carboxyl-terminal peptide (CTP) (T-betacalpha) was slightly decreased but still similar to T-betaalpha. Double mutation at Asn(56) and CTP (T-betacalpha56) caused marked decrease in the activity, indicating that both glycosylations at Asn(56) and CTP are involved in LH-like activity in the tethered form. Interestingly, FSH-like activity remained in all deglycosylated eCG mutants (T-betaalpha56, T-betacalpha and T-betacalpha56) as well as T-betaalpha. The biological roles of oligosaccharides at Asn(56) of eCG alpha-subunit and O-linked peptide of beta-subunit appear to be different in LH- and FSH-like activities in tethered-eCG.  相似文献   

5.
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6.
SUMMARY: Effects of PMSG and genotype on various measures of reproductive efficiency were investigated. Prenatal data were obtained at 40 d of gestation from 96 gilts representing four genotypes. Data on Duroc (D), Yorkshire (Y), Synthetic (Large White × Landrace) (SYN), and Crossbred Duroc × Yorkshire (XB) gilts were collected from January, 1990 through May, 1991. Litter size (LS) data were collected from 482 farrowings of siblings. Treatment with exogenous hormones significantly increased number of corpora lutea (CL), number of embryos (EN), ovum wastage, (OVWS) and embryo length (ELG). Breed group differences (P < .05) were detected for natural ovulation rate, hormone-induced ovulation rate, CL, OVWS, ELG, embryo weight, ovum success, uterine length, ovary weight, range and variance of within-litter embryo weight (RWT and VWT), and litter size born alive. Natural ovulation rates for D, Y, SYN and XB were 10.46 ± 1.61, 12.64 ± 1.41, 14.10 ± .99 and 10.90 ± 1.47, and hormone-induced ovulation rates were 15.00 ± 1.53, 17.69 ± 1.40, 19.43 ± 1.17 and 12.19 ± 1.43, respectively. Range and variance of within-litter embryo length were not affected by either treatment or genotype. Increases in RWT and VWT observed in D and XB gilts after PMSG treatment did not adversely affect embryo survival to 40 d gestation. Significant genetic differences existed for litter size at birth. The PMSG treatment and interactions with PMSG were not significant for litter size born alive. Breed groups seem to differ for CL and EN in response to PMSG but only Yorkshire showed any response in LS (P < .10). Although PMSG increased ovulation rate in siblings by 4.06 ova and number of embryos at 40 d gestation by 1.87 compared with control gilts, there were no differences in litter size born alive due to PMSG treatment. The increase in ovulation rate and number of embryos generated by PMSG seems to be negated by fetal losses occurring both before and after 40 d of gestation. ZUSAMMENFASSUNG: Einflüsse von Stutenserum-Gonadotropin (PMSG) auf Reproduktionsmerkmale von vier Genotypen bei Jungsauen Einflüsse von PMSG und Genotyp auf verschiedene Merkmale der Reproduktion wurden untersucht. Daten wurden am 40. Tr?chtigkeitstag von 96 Jungsauen von vier Genotypen-Duroc (D), Yorkshire (Y), Synthetik (Edelschwein × Landrasse (SYN)) und Kreuzungen-Duroc × Yorkshire (XB) zwischen Januar 1990 und Mai 1991 erhoben. Wurfgr??e (LS) wurden von 492 Würfen von Geschwistertieren erhoben. Behandlung mit exogenem Hormon steigert signifikant die Zahl der Gelbk?rper (CL), Zahl der Embryonen (EN), Ovarverlust (OVWS) und Embryol?nge (ELG). Differenzen zwischen Genotypen wurden für natürliche und hormoninduzierte Ovulationsrate, CL, OVWS, ELG, Embryogewicht, Embryoerfolg, Geb?rmutterl?nge, Ovargewicht, Streuungsbereich und Varianz des Embryogewichtes von Wurfgeschwistern (RWT und VWT) und Zahl lebendgeborener Ferkel erhoben. Die natürlichen Ovulationsraten für D, Y, SYN und XB waren 10,46 ± 1,61, 12,64 ± 1,41, 14,10 ± 0,99 und 10,90 ± 1,47, und die hormoninduzierten 15,00 ± 1,53, 17,69 ± 1,40, 19,43 ± 1,17 und 12,19 ± 1,43. Streuungsbereich und Varianz zwischen Embryonenl?nge eines Wurfes wurden weder durch Behandlung noch Genotyp tangiert. Steigerungen in RWT und VWT in D und XB Jungsauen nach Hormonbehandlung hat Embryoüberleben bis 40 Tage nicht beeintr?chtigt. Signifikante genetische Unterschiede existieren zwischen Wurfgr??e bei Geburt. Hormonbehandlungen und Interaktionen mit Genotypen waren für die Wurfgr??e nicht signifikant. Rassengruppen scheinen für CL und EN im Hinblick auf Hormonbehandlung sich zu unterscheiden, aber nur Yorkshire zeigten Reaktion bei LS (P < .1). Obwohl das Hormon die Ovulationsrate um 4,06 Eier und Zahl der Embryonen bei 40 Tagen um 1,87 gegenüber Kontrollsauen vergr??erte, verblieben keine Unterschiede in Wurf gr??e. Die Steigerung der Ovulationsrate und Zahl der Embryonen nach Hormonbehandlung scheint durch F?talverluste vor und nach 40 Tagen Tr?chtigkeit eliminiert zu werden.  相似文献   

7.
The effects of superovulatory treatment (FSH-P vs human menopausal gonadotropin, HMG) and of route of administration (i.m. vs. i.v.) of prostaglandin F2 alpha (PGF2 alpha) on hormonal profiles were determined in 32 Angus x Hereford heifers. Heifers were superstimulated with either FSH-P (total of 26 mg) or HMG (total of 1,050 IU) beginning on d 9 to 12 of an estrous cycle and PGF2 alpha (40 mg) was administered at 60 and 72 h after the beginning of superovulatory treatments. Heifers were artificially inseminated three times at 12-h intervals beginning 48 h after PGF2 alpha treatment. Blood serum samples were collected immediately before treatments began, at 12-h intervals during the first 60 h, each 4 h during the next 96 h, and each 12 h until day of embryo collection. Concentrations of LH and FSH were not affected by hormone treatments, route of PGF2 alpha injection, or interactions between them. Estradiol-17 beta (E2-17 beta) levels were higher (P less than .05) in HMG- than in FSH-P-treated heifers 60 h after gonadotropin treatment. Peak concentration of E2-17 beta occurred earlier (P less than .05) in HMG- than in FSH-P-treated heifers and earlier in heifers injected with PGF2 alpha i.m. than in those injected i.v. Progesterone concentrations were not influenced by treatment or route of PGF2 alpha administration, but were affected (P less than .01) by the interactions between treatment and route of PGF2 alpha administration. Progesterone declined to basal levels earlier in the FSH-P- than in the HMG-treated heifers.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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9.
AIM: To determine the effect of hCG administration to cycling Thoroughbred mares, on pregnancy and twinning rates and the number of serves in the treated cycle. METHODS: A retrospective case control approach was conducted involving 2119 mare ovulatory cycles, on 1110 mares over a 7-year period. Data were collected by 1 of the authors during routine stud work at 3 commercial Thoroughbred farms in the Waikato region of New Zealand. The hCG (1500 IU) was administered by intravenous injection to selected mares 24 h before the expected time of breeding. Mares were scanned for pregnancy (singleton or twins) 14 days after the onset of dioestrus or detection of ovulation. Multilevel logistic regression analyses were used to identify the risk factors associated with the outcomes of interest while simultaneously controlling for possible confounding factors. RESULTS: Treatment with hCG tended to improve the odds of pregnancy (p=0.06), produced a 3-fold increase in the odds of twins (p<0.001), and increased the odds of a mare having a single serve in the treated ovulatory cycle (p=0.036). The first ovulatory cycle of a season in which a mare was bred was associated with a lower odds of pregnancy (p=0.02), and a lower odds of twins (p=0.003), when compared with subsequent cycles. Lactating mares were less likely to be diagnosed with twins (p=0.005), and were more likely to have a single serve (p<0.001), in any one ovulatory cycle than non-lactating mares. CONCLUSIONS: This report supports the role of hCG as an important therapeutic tool in veterinary management of broodmares for optimal reproductive performance. Mares treated with hCG must be managed in the knowledge that they have an increased likelihood of twins.  相似文献   

10.
The effect of gonadotropin releasing hormone (GnRH) supplement was investigated in twenty eight FSH-treated buffalo cows. Animals were assigned to three groups; Group I: GnRH was given at standing heat (n=9), Group II: GnRH was given 8-12 hr after standing heat (n=8) and Group III: Control group with FSH alone (n=11). The responses (no. of corpora lutea and no. of anovulatory follicles), the number of recovered embryos and transferable embryos among the three groups were compared following slaughter of the animals on days 6 to 7 after first mating. The results indicated that the application of GnRH in FSH-treated animals gave no advantage by increasing in the number of ovulations or recovered embryos in all the treatment groups (P>0.05): 4.33 +/- 3.35 vs 3.88 +/- 4.09 vs 4.5 +/- 2.68 for corpora lutea, and 2.33 +/- 2.24 vs 2.0 +/- 3.20 vs 1.91 +/- 2.74 for recovered embryos respectively. GnRH treatment tended to reduce the number of anovulatory follicles but the finding was not significant; 6.11 +/- 3.3 vs 7.38 +/- 4.84 vs 10.18 +/- 2.74 follilcles (P>0.05). The supplementation of GnRH at 8-12 hr after standing heat seemed to produce more transferable embryos than those of treated at standing heat or the controls 1.63 +/- 2.77 vs 1.25 +/- 1.67 vs 1.36 +/- 1.69 embryos respectively.  相似文献   

11.
Ovarian response of collared peccaries (Pecari tajacu), after hormonal stimulation with gonadotropin association (eCG/hCG), was accessed by both gene expression and follicular development. Thus, collared peccaries (n = 8) were treated with the dose used for sows (swine dose, SWD) or with dose adjusted for peccary's weight (allometric dose, ALD). The gene expression of receptors was evaluated for both gonadotropins (FSHR and LHCGR) and growth factors (proteins codified by TGFβR-1, BMPR1-A and BMPR2 genes) in antral follicles, cortex and corpora haemorrhagica (CH). Five days after gonadotropin injection, all females presented CH. The ovulation rate was similar (p > .05) between SWD (4.00 ± 1.17) and ALD (2.50 ± 0.43) group. The total number of follicles per animal and amounts of small (<3 mm), medium (3–5 mm) and large (>5 mm) follicles was similar among groups. However, SWD produced large follicles heavier than ALD group, as accessed by weight of follicular wall biopsies. Ovarian follicles expressed both gonadotropin and growth factor receptors at levels which are independent from gonadotropin dose. In conclusion, the two gonadotropin doses (SWD and ALD) can be used for ovarian stimulation of collared peccary. Additionally, FSH and growth factors (TGFβR-1, BMPR1-A and BMPR2) receptors are more expressed in the early follicle development, while LH receptor seems to be more important in the final of follicular growth.  相似文献   

12.
In 3 adult female cheetahs, induced-superovulation treatment was conducted, by means of 200 IU of pregnant mare serum gonadotropin (PMSG) and 100 IU of human chorionic gonadotropin (hCG) 80 hr after PMSG. The administration of PMSG created a sharp increase in the estradiol-17beta concentration, resulting in 232 pg/ml 8 hr later in one specimen out of three. The hCG administration showed an increase in the progesterone concentration of 2.29 ng/ml 46 hr later. In addition, after direct observation of the ovary surface by laparoscopy, 5 follicles in the right ovary over 2 mm in diameter, and 7 corpora lutea (5 in the right ovary and 2 in the left) were found. It is assumed that ovulation can be induced with hCG after 80 hr on PMSG during a cheetah's diestrus or proestrus.  相似文献   

13.
The distribution and regulation of annexin A5 expression, a gonadotropin releasing hormone (GnRH) receptor regulated protein in gonadotropes and luteal cells, in the testes of rats were examined. Immunocytochemical staining revealed high levels of annexin A5 in the Leydig and endothelial cells and lower levels in the primary spermatocytes and sperm. Hemicastration significantly increased the annexin A5 content of the remaining testis within 24 h. Annexin A5 immunoreactivity was increased mainly in interstitial tissues including the peritubular cells, while some spermatocytes also showed higher intensity of annexin A5 in the remaining testis. Administration of hCG (50 IU) enhanced the testicular content of annexin A5 after 24 h. This treatment expanded the area of interstitial tissue in the testis and increased annexin A5 immunoreactivity, but the area of the of endothelial cells was unchanged. Similarly, human chorionic gonadotropin (hCG) enhanced annexin A5 expression in a primary culture of testis cells that consisted of mainly interstitial cells. Because GnRH stimulates the expression of annexin A5 in the gonadotropes and luteal cells, we examined the effect of GnRH on annexin A5 expression in the testes. We found that des-Gly10 [Pro9]-GnRH ethylamide (100 nM), a GnRH agonist, increased annexin A5 expression in cultured testis cells and that Cetrorelix (100 nM), a GnRH antagonist, inhibited the effect of hCG on annexin A5 expression. These results suggest that pituitary luteinizing hormone promotes annexin A5 synthesis in Leydig cells and that this effect could be mediated by local GnRH in the testis.  相似文献   

14.
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15.
The object of this investigation was to study the feasibility of using a “Zyklomat roller peristaltic pump” for pulsatile administration of gonadotropin releasing hormone (Gn-RH) in primiparous lactating sows. Four primiparous sows were used. The pump catheter was inserted into a jugular vein on day 8 or day 22 of lactation. The pump delivered a 1 min Gn-RH pulse of 10 μg every 89 min for 7 days. The pump worked without any complication or detrimental effect on the sows throughout the experimental period. Two sows showed standing oestrus during lactation and one of them ovulated. It can be concluded that the “Zyklomat” pump can be used for pulsatile infusion of Gn-RH in lactating sows.  相似文献   

16.
The aim of this study was to evaluate the effects of dose and application time of pregnant mare serum gonadotropin (PMSG) on reproductive performance of hair sheep ewes synchronized with fluorogesterone acetate (FGA) under tropical conditions of Northeastern Mexico. Ninety-nine hair ewes (63 Blackbelly and 36 Pelibuey) were treated with intravaginal sponges during 10 days. After insertion of FGA sponges, ewes were divided into four groups, and PMSG was injected intramuscularly at doses of 100, 200, and 400 IU. Relative to FGA sponge removal, PMSG was administrated at −48 h, −24 h, and at sponge removal. PMSG was not administered to the control group. Control ewes had similar (P > 0.05) lambing rate, fertility, and fecundity than those treated with 100 IU of PMSG, but lower (P < 0.05) percentages to these variables than those treated with 200 and 400 IU of PMSG. Time to estrus decreased linearly, and ovulation rate increased quadratically as PMSG dose increased (0 to 400 IU). Administration of PMSG before sponge removal increased (P < 0.01) response to estrus and decreased (P < 0.01) interval to estrus compared with control. Ovulation rate, lambing rate, fertility, and fecundity were not affected (P > 0.05) by administration time of PMSG. Both dose and time of PMSG application did not affect (P > 0.05) pregnancy rate, percentage of single and multiple lambing, and prolificacy. In conclusion, results show that the dose of 400 IU of PMSG administered before sponge withdrawal in an estrus synchronization protocol improved reproductive efficiency of hair sheep ewes.  相似文献   

17.
The objective of this article was to review the current literature of the influence of gonadotropin releasing hormone (GnRH) and GnRH agonists on conception rate in dairy cattle. The application of GnRH or agonists at artificial insemination (first and subsequent) and between days 7 and 34 after parturition were considered. The variations between studies were discussed as well as different mechanisms concerning the influence of GnRH for establishing pregnancy. From a critical point of view the routine use of GnRH or agonists at the time of first or subsequent breeding or during the postpartum period cannot be supported.  相似文献   

18.
Chlormadinone-acetate and human chorionic gonadotrophin (HCG) were tested for their action on fertility (litter parameters) through 6 generations of laboratory mice. The fertility parameters recorded were in no way indicative of any fertility-depressing effect. HCG acted positively on ovulation rates and also had a somewhat favourable impact on body weight development of the mice involved in testing.  相似文献   

19.
Two experiments were conducted to examine the effect of prostaglandin F2 alpha (PGF2 alpha) and pregnant mares' serum gonadotropin (PMSG) on the reproductive performance (fertility, prolificacy and fecundity) of ewes previously treated with fluorogestone acetate (FGA) and PMSG. In the first experiment, 29 ewes were synchronized for estrus with FGA and PMSG but not bred at the postsynchronization estrus. On day 10 of the first post-synchronization estrous cycle, they were injected IM with 15 mg PGF2 alpha and 500 IU PMSG and exposed to experienced, fertile, raddled rams. Twenty-four of the 29 ewes (83%) had viable fetuses 9 weeks after the PGF2 alpha-PMSG treatment. In the second experiment, 64 ewes were treated with FGA-PMSG, and 33 were exposed to fertile, raddled rams at the synchronized estrus. A second group of 31 ewes was not bred at the synchronized estrus, but on day 12 of the postsynchronized estrous cycle, they were injected IM with 15 mg PGF2 alpha and 500 IU PMSG and exposed to fertile, raddled rams. Sixty-six percent of the 33 ewes lambed in the FGA-PMSG-treated group and 60% of the 31 ewes lambed in the PGF2 alpha-PMSG-treated group. Differences in reproductive performance between these two treatment groups were not statistically significant. The results suggest that the PGF2 alpha-PMSG treatment combination does not adversely affect reproductive performance of ewes.  相似文献   

20.
The synthesis and secretion of trypsin (trypsin model serine protease) inhibitors are regulated in ovarian follicles by gonadotropins. The superovulation stimulations with 400 IU FSH, 1000 IU PMSG, 1000 IU HCG, 750 IIU PMSG + 750 IU HCG influence in a different way the trypsin inhibiting activities (TIA) of blood plasma (BP) (Figs 1 and 2) and follicular fluid (fig. 3); this points to a possibility of local effects. An increase in the average values of TIA in BP was statistically significant during the whole experiment: P less than 0.05 to P less than 0.001 (following the administration of PMSG+HCG, or PMSG, and HCG); Antisergon administered in 68 hours after PMSG reduced this increase. The changes in the fraction of low-molecular TIA in BP (after BP treatment with perchloric acid) were of converse nature; a decrease in the average values ranged from P less than 0.02 to P less than 0.001 (following PMSG or other stimulations). Antisergon did not influence this decrease. The changes observed on particular days of the trial (Figs. 1 and 2) also indicate different effects of the preparations, mainly of the component LH, which resulted in the occurrence of large nonovulating follicles (greater than 10 mm--"cystic" ones). No such follicles were observed in nonstimulated ewes and after FSH stimulation. The administration of antisergon (goat's antiserum against PMSG) 68 hours after PMSG administration did not prevent their creation. The TIA of follicular fluid (FF) of antral follicles was on average tenfold in comparison with that of blood plasma; and the TIA FF of follicles greater than 10 mm was higher (up to P less than 0.001) than the TIA FF of follicles less than 10 mm. The administration of Antisergon in shorter intervals following PMSG administration (12, 24, 48 and 58 hours) influenced the average values of TIA BP in 120 hours (since PMSG administration) in dependence on time (Tab. I). The effects of Antisergon administered in 12 and 24 hours after PMSG administration on the TIA BP were insignificant if it was administered in 48 and 58 hours the TIA BP increased (P less than 0.02; P less than 0.001) in comparison with the interval of 12 hours. The TIA FF of follicles less than 5 mm, 5-10 mm and greater than 10 mm varied in dependence on the time intervals of Antisergon administration (Fig. 4). The statistical significance of these changes in shown in Tab. II.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

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