Effects of Exposure to Male Goat Hair Extracts on Luteinizing HormoneSecretion and Neuronal Activation in Seasonally Anestrous Ewes

[摘要] References(52)Cited-By(2)In sheep and goats, exposureof seasonally anestrous females to males or their fleece/hair activates thegonadotropin-releasing hormone (GnRH) pulse generator leading to pulsatile luteinizinghormone (LH) secretion. Pheromones emitted by sexually mature males are thought to play aprominent role in this male effect. In the present study, we first aimed to clarifywhether the male goat pheromone is effective in ewes. Seasonally anestrous St.Croix ewes were exposed to hair extracts derived from either intact orcastrated (control) male Shiba goats. The male goat-hair extractsignificantly increased LH secretion compared to the control, suggesting that aninterspecies action of the male pheromone occurs between sheep and goats. Using the malegoat-hair extract as the pheromone source, we then aimed to clarify the neural pathwayinvolved in the signal transduction of the male pheromone. Ewes were exposed to either thegoat-hair extract or the control and sacrificed 2 hr after the exposure. Expression ofc-Fos, a marker of neuronal activation, was immunohistochemically examined. The malegoat-hair extract significantly increased the c-Fos expression compared to the control inregions of the vomeronasal system, such as the accessory olfactory bulb and medialamygdala, and the arcuate nucleus. The main olfactory bulb did not exhibit any significantincrease in the c-Fos expression by the male goat-hair extract. This result suggests thatthe neural signal of the male pheromone is conveyed to the GnRH pulse generator throughthe activated regions in ewes.

[学科分类] 兽医学

[关键词] goat;male effect;neural pathway;pheromone;sheep