Effect of high progesterone levels during the growing phase of the dominant follicle of wave 1 in ultrasonically monitored ewes

Rubianes, E.; Castro, T. de; Carbajal, B.

doi:10.4141/cjas96-071

Cited by 49 publications

(18 citation statements)

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“…O diâmetro máximo atingido pelo folículo dominante nos animais controle esteve de acordo com os valores observados por Ravindra et al (1994) e Rubianes et al (1996), sendo menor que os encontrados por Ginther et al (1995) e Leyva et al (1998). A administração da eCG no momento de retirada do dispositivo, possivelmente diminuiu os efeitos negativos de P4 na dinâmica de crescimento folicular e ovulação.…”

Section: Resultsunclassified

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Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

et al. 2002

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RESUMO -Os efeitos de prostaglandina (PGF 2 a) vs CIDR e eCG (gonadotrofina coriônica eqüina) na dinâmica folicular da primeira onda e sua relação com as concentrações plasmáticas de P 4 e E 2 foram investigadas em ovelhas cíclicas. Foram utilizadas 14 fêmeas ovinas da raça Bergamascia; o Grupo 1 (G1) foi submetido a duas aplicações de PGF 2α e o Grupo 2 (G2), tratado com CIDR durante 14 dias, sendo que, no momento de sua retirada, administraram-se 500 UI de eCG. A dinâmica folicular ovariana foi monitorada por meio de ultrasom. Monitoraram-se todos os folículos ≥ 2mm e mapeou-se sua posição diariamente, observando-se o desenvolvimento individual de cada folículo. Desde o dia anterior à aplicação da segunda dose de PGF 2α (G1) e desde a administração de eCG (G2) até o décimo dia do ciclo estral, foram coletadas amostras de sangue para análise de P 4 e E 2 . Houve diferença significativa nas concentrações plasmáticas de P 4 e E 2 entre os tratamentos. A sincronização de estro e ovulação, utilizando CIDR + 500 UI de eCG, incrementou a quantidade de folículos recrutados, além de aumentar o diâmetro máximo e a taxa de crescimento dos folículos grandes na primeira onda folicular.Palavras-chave: dinâmica folicular, estradiol (E 2 ), ovinos, progesterona (P 4 ), ultra-sonografia Endocrine and Ovarian Response Associated with the First-Wave Follicle Dominant in Sheep Synchronized either CIDR or PGF 2αABSTRACT -The effect of prostaglandin (PGF 2 a) vs CIDR and eCG (equine chorionic gonadotrophin) on follicular dynamic of wave 1 and its relation with P 4 and E 2 plasma concentrations were investigated in cyclic ewes. Fourteen Bergamascia ewes were used, Group 1 (G1) synchronized by two i.m. injections of PGF 2α and Group 2 (G2) treated for 14 d with CIDR and 500 IU of eCG at dispositive withdrawal on day 14. Ovarian follicular dynamics were ultrasonically monitored. All the ovarian follicles ≥ 2 mm were measured, and their relative locations were recorded on an ovarian map in order to follow the sequential development of each individual follicle. Blood samples for P 4 and E 2 determination were collected daily from 1 d before the second injection of PGF 2α (G1) and administration of eCG (G2) until day 10 after ovulation of the cycle. There were significant differences in P 4 and E 2 plasma concentrations between treatments. The CIDR + eCG (500 IU) treatment enhanced the recruitment of smaller follicles and enhanced the maximum diameter and growth rate of large follicles during wave 1.

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“…Os dias de platô não apresentaram diferença significativa para os grupos experimentais, sendo para os animais controle e tratados, respectivamente de 1,29 ± 0,18 e 1,57 ± 0,20, similares aos resultados demonstrados por Rubianes et al (1996).…”

Section: Resultsunclassified

Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

et al. 2002

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“…However, this is unlikely as when one administers intramuscularly 20 mg progesterone to hysterectomized ewes, the elimination of the hormone is slower (4 days, fig 3c) than in intact ewes (1 day, Lassoued et al, 1995 (Hunter et al, 1989). Progestagen treatment inhibits the establishment of oxytocin receptors and the release of prostaglandins in response to oxytocin administration (Vallet et al, 1990 (Rubianes et al, 1996) and probably reduces the increase in E2 secretion observed by Mattner and Braden (1972).…”

Section: Methodsmentioning

confidence: 98%

Role of the uterus in early regression of corpora lutea induced by the ram effect in seasonally anoestrous Barbarine ewes

Lassoued¹,

Khaldi²,

Chemineau³

et al. 1997

Reprod. Nutr. Dev.

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Summary -The involvement of the uterus in early regression of corpora lutea induced by the ram effect was studied in seasonally anoestrous Barbarine ewes. In experiment 1, group I was only submitted to the male effect (control, n = 15) while group II (n = 14) was injected every 12 h with flunixin meglumine, a PGF2a synthetase inhibitor (finadyne), from day 3 to day 6 (day 0: day of ram introduction). The preovulatory LH surge appeared at the same time (around 21 h after ram introduction) in both groups. Finadyne treatment significantly decreased 13-14-dihydro-15-keto-PGF2a (PGFM) pulses ( 1.3 ± 0.3 versus 0.4 ± 0.2; P < 0.05), the number of short cycles (50 versus 14%, P < 0.05), and provided a single peak of oestrus, 15-16 days after the introduction of the rams, instead of between day 14 and day 23 (P < 0.01 In experiment 2, 17 hysterectomized ewes were allocated into two groups: group III (n = 8) was injected with oil and group IV (n = 9) received an intramuscular injection of 20 mg of progesterone immediately before introduction of rams. An additional group of intact ewes was used as control (group V, n = 9). Hysterectomy did not affect the ovulation response to the ram effect, but completely suppressed short cycles (0 versus 78% , P < 0.001). The preovulatory LH surge was delayed in hysterectomized females (36.0 ± 14.1 versus 16.6 ± 11.4 h; P < 0.004). Treatment with progesterone significantly (P < 0.01) increased the interval between introduction of rams and the preovulatory LH surge. In conclusion, suppression of short cycles by hysterectomy and an inhibitor of PGF2a synthetase suggest that the uterus is essential for determining the lifespan of ram-induced corpora lutea and that premature release of PGF2a is the cause of early luteal regression. The hypothesis that lower secretion of progesterone before D5 could be the initial cause of the premature induction of the luteolytic signal is discussed.

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“…Daily ultrasound examinations were done by a single operator from the day of the first PGF 2α treatment to one day after the second PGF 2α treatment. The ultrasound scanner was a real-time, B-mode unit (Pie Medical Model 480; Maastricht, The Netherlands) with a 7.5 MHz linear array probe modified to allow manipulation from outside the rectum (Rubianes et al 1996). The size and location of follicles ≥2 mm in diameter were recorded.…”

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confidence: 99%

Origin of the preovulatory follicle after induced luteolysis during the early luteal phase in ewes

Viñoles¹,

Rubianes²

1998

Can. J. Anim. Sci.

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Origin of the preovulatory follicle after induced luteolysis during the early luteal phase in ewes. Can. J. Anim. Sci. 78: 429-431. The origin of the preovulatory follicle (POF) was determined by daily transrectal ultrasonographic examinations in ewes given PGF 2α on day 5 (n = 8) or day 9 (n = 8) post-ovulation. In all day-9 ewes, the POF originated from wave 2 while in the day-5 group it originated from wave 1 (n = 5) or wave 2 (n = 3). When the POF originated from wave 2 in day-5 ewes, the dominant follicle of wave 1 emerged earlier than in ewes with the POF from wave 1 (day -1.0 vs. day 0.8, P < 0.05) and was regressing at the time of PGF 2α treatment (diameter 4.1 ± 0.4 vs. 2.8 ± 0.3 mm, P < 0.05). The dominant follicle of wave 1 became POF if it was in the growing or plateau phase at the time of luteolysis. If it was already in the regressing phase, the dominant follicle of wave 2 became the POF.Key words: PGF 2α , luteolysis, ovarian follicular waves, ultrasonography, ewes Viñoles, C. et Rubianes, E. 1998. Origine du follicule préovulatoire aprés de la luteolysis induite tôt pendant la phase luteále chez les brebis. Can. J. Anim. Sci. 78: 429-431. L' origine du follicule préovulatoire aprés la luteolysis induite avec PGF 2( au cirequième jour (groupe 5, n = 8) et au neuvième jour (groupe 9, n = 8) post-ovulation a été étudié utilisant de la ultrasonographie transrectal journalierè. Dans toutes les brebis du groupe 9, le follicule préovulatoire a été originé a partir de la deuxième vague tandis que ceux du groupe 5 ont été originés à partir de la première vague en 5 brebis et de la deuxième vague en 3. Chez le groupe 5 avec follicule préovulatoire originé dans la deuxième vague, le follicule dominant de la première vague était rétreci le jour de l' administration de la dose de PGF 2α . En conclusion, aprés le traitement avec PGF 2α pendant les premiers jours de la phase luteal, le follicule dominant de la premierè vague s'est tourné en follicule ovulatoire si la luteolysis a été induite pendant son accroissement ou les phases plateaux. Une luteolysis induite plus tardivement conduira au fait que le follicule ovulatoire prendra son origine à partir de la deuxiemè vague.Mots clés: PGF 2α , luteolysis, vagues folliculaires, ultrasonographie, brebisThe injection of an analogue of PGF 2α between days 5 and 14 of the estrous cycle (estrus = day 0) in ewes reliably induces luteal regression, estrus and ovulation (Acritopoulou and Haresign 1980). However, the interval from treatment to estrus is variable, and is apparently affected by day of PGF 2α treatment. In heifers, variation in the interval from PGF 2α treatment to ovulation was attributed to the wave of origin of the ovulatory follicle (Kastelic and Ginther 1991). A wave-like pattern of follicular dynamics has been documented in sheep (Noel et al. 1993;Ginther et al. 1995;Souza et al. 1996). The objective of the present study was to determine the wave of origin of the POF in ewes when luteolyis was induced by giving PGF 2α 5 or 9 d after ovulation (at the e...

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Effect of high progesterone levels during the growing phase of the dominant follicle of wave 1 in ultrasonically monitored ewes

Cited by 49 publications

References 1 publication

Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

Role of the uterus in early regression of corpora lutea induced by the ram effect in seasonally anoestrous Barbarine ewes

Origin of the preovulatory follicle after induced luteolysis during the early luteal phase in ewes

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