Changes in the ovarian dynamics and endocrine profiles in goats treated with a progesterone antagonist during the early luteal phase of the estrous cycle

Suganuma, Chiho; Kuroiwa, Takenobu; Tanaka, Tomomi; Kamomae, Hideo

doi:10.1016/j.anireprosci.2006.09.015

Cited by 20 publications

(19 citation statements)

References 29 publications

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“…Recent studies have revealed the clear wave-like secretion of FSH in daily blood samples in goats [9,27]. The present study also demonstrated that nutritional supplementation promoted the occurrence of a new FSH wave and shortened the interpeak interval of wave-like FSH secretion.…”

Section: Discussionsupporting

confidence: 59%

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The Effects of Short-Term Nutritional Stimulus Before and After the Luteolysis on Metabolic Status, Reproductive Hormones and Ovarian Activity in Goats

Satoko

Kuroiwa

et al. 2009

Journal of Reproduction and Development

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Abstract. The effect of short-term nutritional supplementation on hormonal and ovarian dynamics was studied in goats. Cycling Shiba goats were divided randomly into maintenance (group M, n=4) and high-energy (group H, n=4) groups. After the detection of the ovulation (Day 0, 1 st ovulation), group H received a high-energy diet providing 2.5 times of the maintenance energy requirement for 7 days from Day 7 to Day 13 and were administered 2 mg of prostaglandin F2α (PGF2α) on Day 10 to induce luteal regression followed by the follicular phase. Follicular and luteal dynamics were monitored using ultrasonography daily or every other day, and blood samples were collected daily from Day 0 to the third ovulation (3 rd ovulation) following the second ovulation (2 nd ovulation) induced by PGF2α administration. Blood samples were also collected at 10-min intervals for 6 h on Day 9 and Day 11 for analysis of pulsatile LH secretion. The mean concentrations of glucose and insulin were significantly (P<0.05) higher in group H than in group M on Days 8, 9, 12, 13 and Days 8, 9 and 10, respectively. For both the 2 nd and 3 rd ovulations, no significant difference was detected in ovulation rate between groups M and H. On the other hand, the interpeak interval for wave-like patterns of FSH in group H was significantly (P<0.05) shorter than in group M during the period between the 1 st and 2 nd ovulations (4.3 ± 0.3 vs. 6.5 ± 1.5 days). The mean LH pulse frequency in group H was significantly (P<0.05) greater than in group M on Day 11 (4.5 ± 0.6 vs. 3.3 ± 0.5 pulses/6 h). The present study clearly demonstrated that short-term (7 days) nutritional supplementation promoted pulsatile LH and wave-like FSH secretions in cycling goats. However, no significant increase in ovarian performance was found under such endocrine and metabolic conditions. Key words: Follicle stimulating hormone (FSH), Goat, Luteinizing hormone (LH), Nutritional stimulus, Ovarian activity (J. Reprod. Dev. 55: [39][40][41][42][43][44] 2009) t is well known that nutritional manipulation modulates ovarian functions such as follicular development and ovulation rate in polyovular domestic animals including ewes [1], gilts [2], and goats [3]. There have been several reports of increases in ovulation rate in ewes treated with short-term dietary supplementation of lupin grain, such as for 4 [4], 7 [5], or 11 [6] days during the estrous cycle. Although the nutritional condition in domestic animals has been recognized as a key determinant of reproductive performance, the stimulatory effect of nutritional supplementation on reproductive function remains equivocal. In a recent report that contradicts the above studies, short-term nutritional stimulation of ewes with corn grain and soybean meal during the luteal phase did not increase their ovulation rate [7]. Previous studies have demonstrated that the pattern of daily follicle stimulating hormone (FSH) secretion is wave-like in ewes [8] and goats [9]. There are contradictory results regarding the relationship between ovu...

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Section: Discussionsupporting

confidence: 59%

“…The assay sensitivity was 0.21 μU/ml. The concentrations of LH and FSH were measured by a double-antibody radioimmunoassay with small modifications as described previously [27]. The sensitivity of the assays for LH and FSH were 0.062 and 1.74 ng/ml, respectively.…”

Section: Assaysmentioning

confidence: 99%

The Effects of Short-Term Nutritional Stimulus Before and After the Luteolysis on Metabolic Status, Reproductive Hormones and Ovarian Activity in Goats

Satoko

Kuroiwa

et al. 2009

Journal of Reproduction and Development

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“…The samples were centrifuged at 3000 rpm for 15 min, and the plasma was stored at -30 C until it was assayed for LH. The plasma concentrations of LH were measured in duplicate by a double-antibody radioimmunoassay as described previously [27], except that 100 μl of the plasma samples was used in each assay tube.…”

Section: Blood Sampling and Lh Assaymentioning

confidence: 99%

Effects of Brief Exposure of Male Pheromone on Multiple-Unit Activity at Close Proximity to Kisspeptin Neurons in the Goat Arcuate Nucleus

Murata

Wakabayashi

Sakamoto

et al. 2011

Journal of Reproduction and Development

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Abstract. Exposure of females to the male pheromone induces pulsatile release of gonadotropin-releasing hormone (GnRH) in goats. Recently, kisspeptin neurons in the arcuate nucleus (ARC) have been suggested to represent the proximate source of the GnRH pulse generator. In this study, we examined the effects of the pheromone on multipleunit activity (MUA) in female goats fitted with recording electrodes aimed at the ARC kisspeptin neurons. In all eight goats, periodic bursts in MUA (MUA volleys), which were considered to be electrophysiological manifestations of the GnRH pulse generator, were observed. The mean intervolley interval (T) during the control period was calculated in each goat that was then exposed to the male pheromone for 1 sec at timings of 1/4 T, 1/2 T or 3/4 T after one regularly occurring MUA volley. An instantaneous rise in MUA was observed immediately after the exposure regardless of timing. Exposure at a timing of 3/4 T resulted in an MUA volley within 60 sec following the instantaneous rise in all goats. In contrast, an MUA volley was induced in only 2 goats by exposure at 1/2 T, while exposure at 1/4 T failed to induce an MUA volley in any goats. These results suggest that transmission of the pheromone signal to the ARC, represented by an instantaneous rise, activates the GnRH pulse generator. Moreover, the timing-dependent pheromone action in inducing an MUA volley indicates that the GnRH pulse generator has a refractory period for the pheromone signal after the burst. Key words: GnRH pulse generator, Goat, Kisspeptin, Male effect, Pheromone (J. Reprod. Dev. 57 : 197-202, 2011) n goats and sheep, exposure of seasonally anestrous females to the primer pheromone secreted by sexually mature males results in an out-of-seasonal ovulation [1][2][3][4]. Since the initial endocrine event following reception of the pheromone is the stimulation of pulsatile luteinizing hormone (LH) secretion, it has been thought that the central target of the pheromone signal is the GnRH pulse generator [1,[3][4][5], i.e., the neural substrate that generates intermittent GnRH discharges into the portal vessels, thereby regulating pulsatile LH secretion into the peripheral circulation [6,7].Although the neural identity of the GnRH pulse generator per se was unclear, it was possible to measure its activity by recording multiple-unit activity (MUA) at the mediobasal hypothalamus. It has been demonstrated that electrophysiological manifestations of the GnRH pulse generator are represented as characteristic increases in MUA (MUA volleys) that are exclusively associated with LH pulses in the monkey [8], rat [9] and goat [10,11]. It might be that observed MUA volleys reflect the pulsatile activation of GnRH nerve terminals as they traverse en passant to the ME. Using this technique, Hamada et al. [12] showed that exposure of the female goat to male hair used as a pheromone source promptly induced an MUA volley, demonstrating for the first time that the pheromone action is in fact intimately associated with the GnRH pul...

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“…LH concentrations in plasma were measured for all samples by radio-immunoassay as described previously (Suganuma et al, 2007). Intra-and inter-assay coefficients of variation were 6.1% and 11.9%, respectively, and sensitivity was 0.09 ng/ml.…”

Section: Assaysmentioning

confidence: 99%

Effect of intermittent administration of neurokinin 3 receptor agonist on luteinizing hormone secretion, estrus, and ovulation in feed-restricted goats

Endo

Tanaka

2015

Small Ruminant Research

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Changes in the ovarian dynamics and endocrine profiles in goats treated with a progesterone antagonist during the early luteal phase of the estrous cycle

Cited by 20 publications

References 29 publications

The Effects of Short-Term Nutritional Stimulus Before and After the Luteolysis on Metabolic Status, Reproductive Hormones and Ovarian Activity in Goats

The Effects of Short-Term Nutritional Stimulus Before and After the Luteolysis on Metabolic Status, Reproductive Hormones and Ovarian Activity in Goats

Effects of Brief Exposure of Male Pheromone on Multiple-Unit Activity at Close Proximity to Kisspeptin Neurons in the Goat Arcuate Nucleus

Effect of intermittent administration of neurokinin 3 receptor agonist on luteinizing hormone secretion, estrus, and ovulation in feed-restricted goats

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