AGRIS - Search

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.

Mostrar más [+]

agoniste mares oestrous cycle lh gonadotropin releasing hormone inhibition epoca de apareamiento saison d' accouplement ovulacion 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.

Mostrar más [+]

goats progestational hormones oestrous cycle caprinos corpus luteum fertilite cuerpo luteo ovulacion progestagene 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

taureau fsh trouble fonctionnel size hfs lh tamano testiculos glucocorticoide ...

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

oestrous cycle ovarian cysts kyste ovarien lh gonadotropins gonadotropin releasing hormone suero sanguineo serum sanguin quiste ovarico gonadoliberine ...

Wolters Kluwer - United States of America

Acute testicular atrophy in an active thoroughbred stallion Texto completo

2018

male infertility testes atrophy male genital diseases lh racehorses ...

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

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.

Mostrar más [+]

receptores de hormonas hormone receptors gonadotropins gonadotrophine lh testosteronas recepteur d'hormone reproduccion ...

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

Effects of estradiol benzoate injection to intact and castrated male rabbits on LH, FSH, testeosterone and prostate tissues Texto completo

2016

Tamour Elkhier | Shams-Eldein Hassaballa | Shadia Abdo-Elatti Omer | Abdelnasir Adam

Objective: This study was conducted to investigate the effects of estradiol benzoate injection to intact and castrated male rabbits on LH, FSH, testosterone and prostate tissue. Materials and methods: A total of 72 mature male rabbits were used in this study. The rabbits were randomly divided into two groups (36 intact and 36 castrated) and each group was further divided into four sub-groups. The rabbits of each subgroup were injected estradiol benzoate dosed at 0, 40, 80 and 120 and micro;gm/rabbit, through intramuscular (IM) route, on each alternative day over a period of 30 days. The levels of LH, FSH, and testosterone were measured in serum samples. Prostate tissue samples were taken from each sub-groups, histological examination was done. Results: The mean serum levels of LH and FSH were not affected by injection of estradiol benzoate in all intact and castrated rabbits sub-groups (P>0.05). However, the results of testosterone levels were showed insignificant increase in all intact and castrated male rabbits sub-groups, except the intact male rabbit sub-group that received estradiol benzoate at 120 and micro;g/rabbit (P<0.05). Furthermore, the effects of estradiol benzoate in prostate tissues were ranged from hyperplasia with dysplasia or dysplasia only in intact male rabbits; hyperplasia was represented by papillary projection in castrated male rabbits. Conclusion: The present study revealed no difference in the serum levels of LH, FSH in intact or castrated male rabbits, however, testosterone hormone did not show any change except in sub-group of intact male rabbits that was injected dosed at 120 and micro;g estradiol benzoate. The effect of estradiol benzoate on prostate tissue was found to be induce hyperplasia in both intact and castrated males rabbits. [J Adv Vet Anim Res 2016; 3(4.000): 420-424]

Mostrar más [+]

lh testosterone fsh castrated male rabbit prostate tissues

Directory of Open Access Journals - Sweden

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 ova rats gonadotrophine rata lh ovulo nucleolos division celular nucleole superovulacion maduracion ...

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) Texto completo

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>

Mostrar más [+]

lh ovulação corpo lúteo hcg angiogênese

Universidade de São Paulo - Brazil

Avaliação do uso de Hormônio Luteinizante (LH) como indutor da ovulação em porcas Texto completo

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).

Mostrar más [+]

lh ovulação sincronização suínos gonadotrofinas

Directory of Open Access Journals - Sweden

AGRIS - Sistema Internacional para la Ciencia y Tecnología Agrícola

Share

Fecha de publicación

Idioma

Proveedor de Datos

Procedencia de los datos por país

AGROVOC

Effect of constant administration of a gonadotropin-releasing hormone agonist on reproductive activity in mares: preliminary evidence on suppression of ovulation during the breeding season.

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.

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

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

Acute testicular atrophy in an active thoroughbred stallion Texto completo

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)

Effects of estradiol benzoate injection to intact and castrated male rabbits on LH, FSH, testeosterone and prostate tissues Texto completo

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

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) Texto completo

Avaliação do uso de Hormônio Luteinizante (LH) como indutor da ovulação em porcas Texto completo