Data/hora: 25/06/2024 08:59:03

Biblioteca(s): | Embrapa Caprinos e Ovinos.
Data corrente: | 01/04/2005
Data da última atualização: | 30/11/2023
Autoria: | MEIKLE, A.; FORSBERG, M.; GARÓFALO, E. G.; RODRIGUÉZ, A.
Título: | Gonadotropins and follicular response after treatment with estradiol in anestrous ewes.
Ano de publicação: | 2002
Fonte/Imprenta: | Theriogenology, v. 53, n. 1, p. 377, 2000.
Idioma: | Inglês
Notas: | Edição de proceedings Annual Conference of the International Embryo Transfer Society, Maastricht, The Netherlands, jan. 2000.
Conteúdo: | The aim of this study was to determine the effects of estradiol (E2) on circulating gonadotropin levels and on ovarian follicular dynamics in anestrous ewes. Corriedale ewes received a corn oil injection (0.1 mL/kg, Group C, n=4) or an im injection of E2-17b in corn oil vehicle (1 m/kg, Group E, n=7) during the non-breeding season. Blood samples for determination of progesterone (P4), LH and FSH by RIA were collected daily 4 d before  the treatment (Day 0). From 2 h before until 56 h after treatment, samples were taken every 2 h, and from then on every 6 h until the end of the experirnent (Day 9). During Day -4 to Day 9, transrectal ultrasonic examinations were carried out daily using an Aloka SSD 500 uhrasound with a 7.5 MHz linear array probe. Numbers and gizes of follicles larger than 3 mm were recorded. Data were analyzed by repeated measures ANOVA in the GLM procedure. AlI data are presented as means + SEM. Serurn levels of LH and FSH during the  2 h bleeding period are shown in Fig 1. On1y in Group E could LH and FSH surges be observed 12 to 18 h after injection. P4 levels remained low <0.7 nmol/L) before, during and after the treatment in both groups. No ovulations were recorded by ultrasonography in any ewe. The diameter of the largest follicle in the ewes of group E decreased and was minimal (P<0.05) 3 d post-treatment (Fig. 2), while no effect was observed in Group C. The emergence of a new wave in this group occurred 2.4+O.4 d after the E2  injection. LH and FSH surges were not able to provoke ovulation. In contrast, the treatment was associated with regression of the largest follicle suggesting an inhibitory action of E2. Results suggest that the treatment provoked a synchronous emergence of a new wave.
Palavras-Chave: | Anestro; FSH; Gonodotropina; LH.
Thesagro: | Ciclo Estral; Endocrinologia; Estradiol; Hormônio; Ovelha; Ovino; Reprodução Animal.
Categoria do assunto: | --
Registro original: | Embrapa Caprinos e Ovinos (CNPC)
Exemplares: | CNPC - (17585-1) - ADD - RA - PP -  -  - v.53,p.377 - DIS