Stimulation of the GnRH Pulse Generator Activity by Continuous Exposure to the Male Pheromones in the Female Goat.

Ichimaru, Toru; Takeuchi, Yukari; Mori, Yuji

doi:10.1262/jrd.45.243

Cited by 21 publications

(11 citation statements)

References 28 publications

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“…The refractory mechanism of the GnRH pulse generator may have some important biological significance. We have shown that continuous exposure of a female goat to the pheromone results in frequent MUA volleys, each of which is associated with an LH pulse [28]. This suggests that although the pheromone signal is continuously transmitted to the GnRH pulse generator, the refractory mechanism seemingly operates to generate intermittent bursts during the exposure; otherwise the pulse generator would become continuously activated.…”

Section: Discussionmentioning

confidence: 98%

“…In previous studies, the effect of the male pheromone on GnRH pulse generator activity was monitored by recording MUA at the ARC/ME region [12,15,16,28]. Since recent reports suggest that a group of kisspeptin neurons in the ARC is a likely candidate for the GnRH pulse generator [19,20,29], we reexamined the action of the male pheromone by measuring MUA through electrodes aimed at the ARC kisspeptin neurons of the goat in this study.…”

Section: Discussionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

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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“…The response to the male effect is multisensorial but the respective role of the different male sensory cues remains unclear. It is clearly established that olfactory cues play a critical role and can partially mimic the male effect; in fact, in goats (does) and sheep (ewes), exposure to hair or fleece of males stimulates the activity of GnRH neurons, LH secretion and ovulation (Claus et al, 1990;Cohen-Tannoudji and Signoret, 1987;Gelez et al, 2004a;Ichimaru et al, 1999;Knight and Lynch, 1980). However, the response of ewes to olfactory cues depends on their previous sexual experience, since the odor provided by the male fleece stimulates LH secretion in sexually experienced ewes, but not in sexually naive ones (Gelez et al, 2004a).…”

Section: Introductionmentioning

confidence: 99%

Male goat vocalizations stimulate the estrous behavior and LH secretion in anestrous goats that have been previously exposed to bucks

Delgadillo

Vielma

Hernández

et al. 2012

Hormones and Behavior

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“…The pheromone activity was examined as described previously [7][8][9][10][11]. In brief, on the day of bioassay, the sample was dissolved in diethyl ether.…”

Section: Skin Samples and Bioassay For Pheromone Activitymentioning

confidence: 99%

“…Consequently, two studies demonstrated that exposure to the hair collected from mature male goats induced an immediate characteristic increase in the MUA (MUA volley) in female goats [7,8]. Using the MUA technique as a bioassay system to assess the pheromone activity, Iwata et al [9] demonstrated in castrated male goats that treatment with testosterone (T) for 28 days induced production of the male effect pheromone in the head skin, and that the pheromone activity in the skin sample disappeared within 14 days after cessation of the T treatment.…”

mentioning

confidence: 99%

Androgen Induces Production of Male Effect Pheromone in Female Goats

Kakuma

Ichimaru

Yonezawa

et al. 2007

Journal of Reproduction and Development

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Abstract. Previously we showed that the primer pheromone responsible for the "male effect" was produced in specific skin regions of castrated male goats by androgen treatments. In the present study, we examined whether androgen can also induce production of the male effect pheromone in female goats. Capsules containing dihydrotestosterone (DHT) or testosterone (T) were subcutaneously implanted into six ovariectomized (OVX) goats for 28 days. Small skin samples were collected from the head and rump regions, and the pheromone activity of their ether extracts was examined using a bioassay that monitors the electrophysiological manifestation of the hypothalamic gonadotropin-releasing hormone pulse generator as multiple-unit activity. Behaviors of OVX goats towards ovary-intact estrous goats were also examined before and at the end of DHT or T treatment. Before androgen treatment, neither the head nor rump skin samples in OVX goats showed pheromone activity. DHT treatment induced pheromone activity in the head skin sample of six OVX goats and in the rump skin sample of two OVX goats. Similar results were obtained by T treatment. In addition, OVX goats treated with T showed masculine-type sexual behaviors such as courtship and mounting behaviors towards the estrous goats. These results demonstrate that androgen is capable of inducing primer pheromone activity in the female and suggest that the synthesis pathway of the male effect pheromone exists in both sexes in the goat.

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Stimulation of the GnRH Pulse Generator Activity by Continuous Exposure to the Male Pheromones in the Female Goat.

Cited by 21 publications

References 28 publications

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

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

Male goat vocalizations stimulate the estrous behavior and LH secretion in anestrous goats that have been previously exposed to bucks

Androgen Induces Production of Male Effect Pheromone in Female Goats

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