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During the breeding season, the effect of constant administration of an agonist analog of gonadotropin-releasing hormone (GnRH; goserelin acetate) on reproductive activity of mares was determined. Twenty-four mares undergoing estrous cycles were allocated at random to 6 groups (n = 4/group) and, on May 29 (day 0), received no treatment (group 1, controls), 120 micrograms (group 2), 360 micrograms (group 3), 600 micrograms (group 4), or 1,200 micrograms (group 5) of GnRH agonist/d for 28 days via a depot implanted subcutaneously. The final group of mares (group 6) was treated with 120 miocrograms of GnRH agonist/d for 84 days (3 occasions at 28-day intervals). During a pretreatment period (April 19 to May 29) and for 90 days after initiation of GnRH agonist treatment, follicular development and ovulation were monitored by transrectal ultrasonography of the reproductive tract at 2- to 3-day intervals. On each occasion a blood sample was collected for determination of luteinizing hormone (LH) and progesterone. Estrous behavior was monitored by teasing of mares with a stallion. Initiation of agonist treatment was random, relative to the stage of the estrous cycle, and all mares ovulated within 11 days before or after implantation. in 3 of 4 nontreated control mares, estrous cycles were observed throughout the study, with interovulatory intervals ranging from 18 to 26 days. In the remaining mare, concentration of progesterone was high after asynchronous double ovulation during the pretreatment period, suggestive of persistent corpus luteum. In group-2 mares, ovulation occurred in all mares 7 days before and 2 days after initiation of treatment; however, the next anticipated ovulation was delayed in 3 of 4 mares (interovulatory interval, 33 to 70 days). Estrous cycles were not disrupted in the remaining mare. At higher doses (groups 3-5), 1 mare each from groups 3 and 5 ovulated between days 0 and 2 of treatment initiation.

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ciclo estral inhibition lh progesterone hormona liberadora de gonadotropina agonists saison d' accouplement ovulacion epoca de apareamiento inhibicion gonadoliberine ...

Wolters Kluwer - United States of America

Luteinizing hormone and progesterone concentrations and induction of estrus after use of norgestomet ear implants or constant infusion of gonadotropin-releasing hormone in anestrous, nonlactating dairy goats.

1991

Plasma luteinizing hormone and progesterone concentrations, time to onset of estrus, and pregnancy rates were determined in nonlactating anestrous does given 1 of 4 treatments: subcutaneous ear implants containing 3 mg of norgestomet for 9 days (NOR; n = 6); subcutaneous administration, using osmotic minipumps, of 250 ng of gonadotropin-releasing hormone (GnRH)/h for 48 hours (GnRH; n = 6); 3 mg of NOR for 9 days, followed immediately by 250 ng of GnRH/h for 48 hours (NOR + GnRH; n = 6); or no treatment (control; n = 6). During the 72-hour period after removal of NOR or insertion of GnRH pumps, 6 of 6, 0 of 6, 6 of 6, and 3 of 6 does were observed in estrus at a mean (+/- SE) of 49 (+/- 3.0), 0(+/- 0), 32 (+/- 2.0), and 35 (+/- 13.8) hours in groups NOR, GnRH, NOR + GnRH, and control, respectively. Time from end of treatment to peak concentrations of luteinizing hormone were 56 +/-4.0, 28 +/- 4.7, 34 +/- 4.3, and 41 +/- 9.7 hours (mean +/- SE) for NOR, GnRH, Nor +/- GnRH, and control, respectively. Peak concentrations of luteinizing hormone were significantly greater and occurred significantly later in does given NOR. Progesterone concentrations in does that became pregnant increased to concentrations greater than or equal to 1.0 ng/ml 3 to 5 days after breeding and remained high. Functional corpora lutea (CL) was found in 6 does that did not become pregnant, 1 CL was associated with pseudopregnancy and 1 CL was associated with ovulation prior to placement of the GnRH pumps. Functional CL failed to form in 10 of the 12 does in groups GnRH and control. Does had either continual low concentrations of progesterone (3 does) or short-term increases in concentrations of progesterone (7 does). Conception rates for does in groups NOR, GnRH, NOR + GnRH, and control were 83%, 0%, 50% and 0%, respectively. Four does given GnRH and 3 control does were observed in estrus and were bred during the subsequent 2-week period. All of these does, except 1 control became pregnant subsequent to these breedings. The treatments NOR and NOR + GnRH were effective in inducing a synchronized estrus in dairy goats. However, the use of bucks to detect estrus may have introduced the buck effect and enhanced the performance of NOR alone, which has not been this effective in other studies with small ruminants.

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ciclo estral corpus luteum lh progesterone hormona liberadora de gonadotropina fertility cuerpo luteo ovulacion progestagene gonadoliberine ...

Wolters Kluwer - United States of America

Relationship between serum total cholesterol levels on the day of hormonal treatment and the subsequent ovarian response in ovarian cystic cows.

1986

ciclo estral gonadotropinas cows lh hormona liberadora de gonadotropina vache quiste ovarico suero sanguineo serum sanguin gonadoliberine ...

Wolters Kluwer - United States of America

Pathophysiology of small testes in beef bulls: relationship between scrotal circumference, histopathologic features of testes and epididymides, seminal characteristics, and endocrine profiles.

1986

toro escroto scrotum semen sperme lh glucocorticoide tamano testiculos ...

Wolters Kluwer - United States of America

Changes in plasma gonadotropins inhibin and testosterone concentrations and testicular gonadotropin receptor mRNA expression during testicular active, regressive and recrudescent phase in the captive Japanese black bear (Ursus thibetanus japonicus)

2010

Male Japanese black bears (Ursus thibetanus japonicus) have an explicit reproductive cycle. The objective of this study was to clarify the variation of plasma testosterone, FSH, inhibin, LH levels and testicular gonadotropin receptor mRNA expression of male bears associated with their testicular activity. Notably, this study investigated peripheral FSH concentration and localization of gonadotropin receptor mRNAs for the first time in male bears. Blood and testicular tissue samples were taken from captive, mature, male Japanese black bears during testicular active, regressive and recrudescent phases. Plasma hormone concentrations were measured by immunoassays, and gonadotropin receptor mRNA expression in the testis was investigated by in situ hybridization technique and also by real-time PCR. There were significant variations in plasma testosterone and inhibin concentrations. Changes in FSH concentration preceded these hormones with a similar tendency. Hormones started to increase during denning, and achieved the highest values at the end of the recrudescent phase for FSH and in the active phase for testosterone and inhibin. These changes in hormone concentrations were accompanied by testicular growth. In situ hybridization analysis revealed that FSH and LH receptor mRNA was possibly expressed in Sertoli cells and Leydig cells, respectively, as they are in other mammals. However, neither plasma LH concentration nor testicular gonadotropin receptor mRNA expression level varied significantly among the sampling months. These results suggest that FSH, inhibin and testosterone have roles in testicular activity in male bears. This study provides important endocrine information for comprehending seasonal reproductivity in male Japanese black bears.

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reproduction hormone receptors gonadotropinas receptores de hormonas gonadotrophine testosteronas reproduccion recepteur d'hormone ...

The Agriculture, Forestry and Fisheries Research Information Technology Center - Japan

Serum luteinizing hormone response and oocyte nuclear maturation in rats superovulated with pregnant mare serum gonadotropin

1994

Yun, Y.W. (Chungbuk National University, Cheongju (Korea Republic). College of Veterinary Medicine)

maturation nucleolus rata superovulation rat gonadotrophine division celular maduracion nucleolos ovulo superovulacion nucleole ...

Korea Agricultural Science Digital Library - Republic of Korea

Faillure in the effect of the analogue (hCG) of luteinizing hormone on the luteal angiogenesis in rats (Rattus novergicus) | Ausência de efeito do análogo (hCG) do hormônio luteinizante na angiogênese luteal em ratas (Rattus novergicus)

2013

<p class="MsoNormal"><span style="mso-ansi-language: EN-US;" lang="EN-US">The knowledge of the mechanisms that affect the control of the ovarian activity is essential for the success of reproduction biotechnologies. Although a number of studies have been carried out in which the luteinizing hormone (LH) was used to control the ovarian activity, little is known about its influence in the morphology and vascular formation of the corpus luteum, aiming to increase the local blood flow. Thus, the objective of the present experiment was the quantification of the vascular density of corpora lutea (Cls) in animals treated with human chorionic gonadotropin (hCG) just after ovulation. Therefore, eighteen wistar rats were used in this experiment. Eight rats in the treated group and ten rats in the control group. Corpora lutea were divided into two groups: group (A) treated with hCG in the following morning after copulation, and group (B) control animals which received an injection of 0.9% sodium chloride solution. Ovaries from each group were used for preparation of histological sections for vascular density qualification. No statistical significance was found between the two groups tested.</span></p> | <p class="MsoNormal">A compreensão dos mecanismos de controle da atividade ovariana é necessária para o sucesso das biotecnologias da reprodução. Embora existam inúmeros trabalhos a respeito da aplicação do hormônio luteinizante (LH) na função ovariana, pouco se sabe sobre a sua influência na morfologia e formação da vasculatura do corpo lúteo (CL). Diante disto, o presente projeto teve como objetivo a quantificação da densidade vascular dos CLs de animais tratados com Gonadotrofina Corionica Humana (hCG) após a ovulação. Para tanto, foram utilizados ratas wistar, cujos CLs foram divididos em dois grupos: (A) tratado com hCG na manhã seguinte a cópula e (B) controle (solução fisiológica a 0,9 % de NaCl). Foram confeccionadas lâminas dos ovários dos animais para a quantificação da densidade vascular. Os resultados obtidos não revelaram diferenças significantes entre a densidade vascular dos grupos tratado e controle.</p>

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ovulação corpo lúteo lh hcg angiogênese

Universidade de São Paulo - Brazil

Avaliação da liberação de LH e da concentração de progesterona em protocolos Ovsynch e Heatsynch em bubalinos (Bubalus bubalis) | Evaluation of lh surge and progesterone concentration in ovsynch and heatsynch protocols in buffalo (Bubalus bubalis)

2007

Rodolfo Cassimiro de Araújo Berberi | Ciro Moraes Barrosi | Guilherme Paula Nogueira | Pietro Sampaio Baruselli

O objetivo desse estudo foi avaliar a liberação de LH durante os protocolos de sincronização da ovulação em bubalinos. Para tanto, quinze búfalas multíparas receberam 25 mg de Lecirelina no Dia 0, e 150 mg de D-Cloprostenol no Dia 7. No Dia 8, foi aplicado benzoato de estradiol nas búfalas do Grupo 1 (0,5 mg, n = 5) e do Grupo 2 (1,0 mg, n = 5). No Dia 9, os animais receberam 25mg de Lecirelina (Controle, n = 5). Para mensuração das concentrações plasmáticas de LH foram colhidas amostras de sangue da veia jugular no Dia 7, e em seguida em intervalos de 3 horas até completar 72 horas após a aplicação de PGF2a. Para avaliação da liberação de LH foram comparados os momentos de ocorrência do pico LH em relação à PGF2a, as durações, as amplitudes e a área sob o pico de pré-ovulatório de LH. As búfalas dos Grupos Controle, 1 e 2 apresentaram picos pré-ovulatórios de LH em 51 + 0,0 horas, 47,3 + 2,7 horas e 47,0 + 3,8 horas após a aplicação da PGF2a, respectivamente (P>;0,05). A duração do pico de LH foi menor no Controle (7,8 + 1,5 horas) do que nos Grupos 1 e 2 (10,5 + 1,5 horas vs. 10,8 + 2,4 horas, respectivamente; P < 0,05). A amplitude média dos picos pré-ovulatórios de LH foram de 4,5 + 0,4 ng/mL, 4,0 + 0,4 ng/mL e 4,3 + 0,8 ng/mL para os Grupos Controle, 1 e 2, respectivamente (P >; 0,05). A área sob o pico de LH no Controle (4,8 ± 0,7) foi menor do que as áreas dos Grupos 1 e 2 (8,8 ± 2,5 vs. 8,7 ± 2,2, respectivamente; P < 0,05). Em resumo, a aplicação de benzoato de estradiol proporcionou maior duração e área do pico pré-ovulatório de LH do que a administração de GnRH em protocolos Ovsynch em bubalinos. | The objective of this study was to evaluate the LH surge after last hormonal injection of synchronization of ovulation protocols in buffalo. Fifteen multiparous buffaloes received 25 mg of Lecirelin in Day 0, and 150 mg of D-Cloprostenol on Day 7. On Day 8, estradiol benzoate was injected in Group 1 (0.5 mg, n = 5) and Group 2 (1.0 mg, n = 5). On Day 9, five buffaloes received 25 mg of Lecirelin (Control). Blood samples were collected for measure the LH concentrations on Day 7 and then every 3 hours until 72 hours after the PGF2a injection. For evaluation of LH surge were compared the interval between PGF2a injection to LH surge, duration, amplitude and area under the LH peak. The LH surge occurred 51.0 + 0.0 hours, 47.3 + 2.7 hours and 47.0 + 3.8 hours after PGF2a injection for Control, Group 1 and Group 2, respectively (P >; 0.05). The duration of LH peak in Control (7.8 + 1.5 hours) was shorter than Groups 1 and 2 (10.5 + 1.5 hours vs. 10.8 + 2.4 hours, respectively; P < 0.05). The amplitudes of LH peak were 4.5 + 0.4 ng/mL, 4.0 + 0.4 ng/mL and 4.3 + 0.8 ng/mL for Control, Group 1 and Group 2, respectively (P >; 0.05). The area under LH peak for Control (4.8 ± 0.7) was smaller than the areas of the Groups 1 and 2 (8.8 ± 2.5 vs. 8.7 2.2, respectively; P < 0.05). In summary, the estradiol benzoate injection provided higher duration and area of LH peak than GnRH injection in Ovsynch protocol in buffalo.

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lh ovsynch sincronização da ovulação búfalos heatsynch

Universidade de São Paulo - Brazil

Avaliação do uso de Hormônio Luteinizante (LH) como indutor da ovulação em porcas | Assessment of the Luteinizing Hormon (LH) use in ovulation induction in sows

2004

A pesquisa, desenvolvida num sistema de produção de suínos, estudou a efetividade do hormônio luteinizante (LH) na indução das ovulações. Vinte e quatro fêmeas constituíram o grupo controle e trinta e duas receberam a injeção intramuscular de 600 UI de eCG (Novormon 5000®), 24 h após a desmama e 5 mg de LH (Lutropin - V ®), 56 h após a injeção de eCG, caracterizando o grupo tratado. O estro foi observado 2 vezes ao dia, a ovulação detectada por ultra-sonografia transcutânea e taxa de ovulação (TO) determinada por contagem de corpos lúteos. O intervalo desmama-estro (IDE) foi reduzido (P = 0,01) pelo tratamento (87,4 vs 98,5 horas). As ovulações ocorreram entre 32 e 48 h (37,25 ± 3,65) após LH e foi diferente (P < 0,0001) do controle (63,67 ± 20,22, variando de 32 a 104 h). A TO do tratamento foi semelhante (P = 0,2) à do controle (23,16 ± 12,19 vs 20,08 ± 5,19, respectivamente). | The research, developed in a swine production system, examined the effectivity of luteinizing hormone (LH) in ovulation induction. Twenty four sows compose the control group and tirthy two sows received intramuscular aplication of 600 IU of eCG (Novormon 5000®), 24 h after weaning and 5 mg of LH (Lutropin - V ®), 56 h after eCG injection (treated group). Oestrus were observed twice a day, the ovulation detected by transcutaneous ultrasonography and ovulation rate (OR) determined by corpora lutea counting. The weaning-to-estrus interval (WEI) were reduced (P=0,01) by treatment (87,4 vs 98,5 h). The ovulations occured among 32 and 48 h (37,25 ± 3,65) after LH and were diferent (P < 0,0001) of control (63,67 ± 20,22, range: 32 - 104 h). The OR of treatment was similar (P = 0,2) on the control (23,16 ± 12,19 vs 20,08 ± 5,19, respectively).

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sincronização ovulação lh gonadotrofinas suínos

Universidade de São Paulo - Brazil

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