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Effects of exposure to male goat hair extracts on luteinizing hormone secretion and neuronal activation in seasonally anestrous ewes.

Ohara H, Mogi K, Ichimaru T, Ohkura S, Takeuchi Y, Mori Y, Okamura H - J. Vet. Med. Sci. (2014)

Bottom Line: The male goat-hair extract significantly increased the c-Fos expression compared to the control in regions of the vomeronasal system, such as the accessory olfactory bulb and medial amygdala, and the arcuate nucleus.The main olfactory bulb did not exhibit any significant increase in the c-Fos expression by the male goat-hair extract.This result suggests that the neural signal of the male pheromone is conveyed to the GnRH pulse generator through the activated regions in ewes.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.

ABSTRACT
In sheep and goats, exposure of seasonally anestrous females to males or their fleece/hair activates the gonadotropin-releasing hormone (GnRH) pulse generator leading to pulsatile luteinizing hormone (LH) secretion. Pheromones emitted by sexually mature males are thought to play a prominent role in this male effect. In the present study, we first aimed to clarify whether the male goat pheromone is effective in ewes. Seasonally anestrous St. Croix ewes were exposed to hair extracts derived from either intact or castrated (control) male Shiba goats. The male goat-hair extract significantly increased LH secretion compared to the control, suggesting that an interspecies action of the male pheromone occurs between sheep and goats. Using the male goat-hair extract as the pheromone source, we then aimed to clarify the neural pathway involved in the signal transduction of the male pheromone. Ewes were exposed to either the goat-hair extract or the control and sacrificed 2 hr after the exposure. Expression of c-Fos, a marker of neuronal activation, was immunohistochemically examined. The male goat-hair extract significantly increased the c-Fos expression compared to the control in regions of the vomeronasal system, such as the accessory olfactory bulb and medial amygdala, and the arcuate nucleus. The main olfactory bulb did not exhibit any significant increase in the c-Fos expression by the male goat-hair extract. This result suggests that the neural signal of the male pheromone is conveyed to the GnRH pulse generator through the activated regions in ewes.

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Photomicrographs of c-Fos-ir cells in several brain regions in seasonally anestrousewes exposed to the control (left column) or goat pheromone (right column). A, mainolfactory bulb (MOB). B, piriform cortex (PYR). C, accessory olfactory bulb (AOB). D,medial amygdala (MeA). E, anterior part of the bed nucleus of the stria terminalis(BNSTa). F, arcuate nucleus (ARC). Sections were briefly counter-stained for Nissl.Arrowheads indicate representative c-Fos-ir materials. GL, glomerular layer; GRL,granule cell layer; ML, mitral cell layer; MTL, mitral/tufted cell layer, LV, lateralventricle; 3V, third ventricle. Scale bars, 100 µm.
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fig_003: Photomicrographs of c-Fos-ir cells in several brain regions in seasonally anestrousewes exposed to the control (left column) or goat pheromone (right column). A, mainolfactory bulb (MOB). B, piriform cortex (PYR). C, accessory olfactory bulb (AOB). D,medial amygdala (MeA). E, anterior part of the bed nucleus of the stria terminalis(BNSTa). F, arcuate nucleus (ARC). Sections were briefly counter-stained for Nissl.Arrowheads indicate representative c-Fos-ir materials. GL, glomerular layer; GRL,granule cell layer; ML, mitral cell layer; MTL, mitral/tufted cell layer, LV, lateralventricle; 3V, third ventricle. Scale bars, 100 µm.

Mentions: Schematic illustrations of brain regions. A, a sagittal view of the olfactory bulb.B–E, coronal views of the hypothalamus and the amygdaloid complex (the rostro-caudalorder). Gray squares schematically show the areas in which the number of c-Fospositive cells was counted in each brain region. AAA, anterior amygdaloid area; ACo,anterior cortical amygdala; AHA, anterior hypothalamic area; AOB, accessory olfactorybulb; ARC, arcuate nucleus; BA, basal amygdala, BNSTa, anterior part of the bednucleus of the stria terminalis; BNSTp, posterior part of the bed nucleus of the striaterminalis; CA, caudate nucleus; CeA, central amygdala; DMH, dorsomedial hypothalamicnucleus; En, endopiriform nucleus; LA, lateral amygdala; LHA, lateral hypothalamicarea; MeA, medial amygdala; MOB, main olfactory bulb; MPOA, medial preoptic area;OVLT, vascular organ of the lamina terminalis; PMCo, posterior medial corticalamygdala; PLCo, posterior lateral cortical amygdala; POA, preoptic area; PUT, putamen;PVN, paraventricular nucleus of the hypothalamus; PYR, piriform cortex; Sch,suprachiasmatic nucleus; SON, supraoptic nucleus; VMH, ventromedial hypothalamicnucleus, GL, glomerular layer; GRL, granule cell layer; ML, mitral cell layer; MTL,mitral/tufted cell layer; ac, anterior commissure;fx, fornix; och, optic chiasm;ot, optic tract; st, stria terminalis;stm, stria medullaris of the thalamus; LV, lateralventricle; ME, median eminence; 3V, thirdventricle.


Effects of exposure to male goat hair extracts on luteinizing hormone secretion and neuronal activation in seasonally anestrous ewes.

Ohara H, Mogi K, Ichimaru T, Ohkura S, Takeuchi Y, Mori Y, Okamura H - J. Vet. Med. Sci. (2014)

Photomicrographs of c-Fos-ir cells in several brain regions in seasonally anestrousewes exposed to the control (left column) or goat pheromone (right column). A, mainolfactory bulb (MOB). B, piriform cortex (PYR). C, accessory olfactory bulb (AOB). D,medial amygdala (MeA). E, anterior part of the bed nucleus of the stria terminalis(BNSTa). F, arcuate nucleus (ARC). Sections were briefly counter-stained for Nissl.Arrowheads indicate representative c-Fos-ir materials. GL, glomerular layer; GRL,granule cell layer; ML, mitral cell layer; MTL, mitral/tufted cell layer, LV, lateralventricle; 3V, third ventricle. Scale bars, 100 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221165&req=5

fig_003: Photomicrographs of c-Fos-ir cells in several brain regions in seasonally anestrousewes exposed to the control (left column) or goat pheromone (right column). A, mainolfactory bulb (MOB). B, piriform cortex (PYR). C, accessory olfactory bulb (AOB). D,medial amygdala (MeA). E, anterior part of the bed nucleus of the stria terminalis(BNSTa). F, arcuate nucleus (ARC). Sections were briefly counter-stained for Nissl.Arrowheads indicate representative c-Fos-ir materials. GL, glomerular layer; GRL,granule cell layer; ML, mitral cell layer; MTL, mitral/tufted cell layer, LV, lateralventricle; 3V, third ventricle. Scale bars, 100 µm.
Mentions: Schematic illustrations of brain regions. A, a sagittal view of the olfactory bulb.B–E, coronal views of the hypothalamus and the amygdaloid complex (the rostro-caudalorder). Gray squares schematically show the areas in which the number of c-Fospositive cells was counted in each brain region. AAA, anterior amygdaloid area; ACo,anterior cortical amygdala; AHA, anterior hypothalamic area; AOB, accessory olfactorybulb; ARC, arcuate nucleus; BA, basal amygdala, BNSTa, anterior part of the bednucleus of the stria terminalis; BNSTp, posterior part of the bed nucleus of the striaterminalis; CA, caudate nucleus; CeA, central amygdala; DMH, dorsomedial hypothalamicnucleus; En, endopiriform nucleus; LA, lateral amygdala; LHA, lateral hypothalamicarea; MeA, medial amygdala; MOB, main olfactory bulb; MPOA, medial preoptic area;OVLT, vascular organ of the lamina terminalis; PMCo, posterior medial corticalamygdala; PLCo, posterior lateral cortical amygdala; POA, preoptic area; PUT, putamen;PVN, paraventricular nucleus of the hypothalamus; PYR, piriform cortex; Sch,suprachiasmatic nucleus; SON, supraoptic nucleus; VMH, ventromedial hypothalamicnucleus, GL, glomerular layer; GRL, granule cell layer; ML, mitral cell layer; MTL,mitral/tufted cell layer; ac, anterior commissure;fx, fornix; och, optic chiasm;ot, optic tract; st, stria terminalis;stm, stria medullaris of the thalamus; LV, lateralventricle; ME, median eminence; 3V, thirdventricle.

Bottom Line: The male goat-hair extract significantly increased the c-Fos expression compared to the control in regions of the vomeronasal system, such as the accessory olfactory bulb and medial amygdala, and the arcuate nucleus.The main olfactory bulb did not exhibit any significant increase in the c-Fos expression by the male goat-hair extract.This result suggests that the neural signal of the male pheromone is conveyed to the GnRH pulse generator through the activated regions in ewes.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.

ABSTRACT
In sheep and goats, exposure of seasonally anestrous females to males or their fleece/hair activates the gonadotropin-releasing hormone (GnRH) pulse generator leading to pulsatile luteinizing hormone (LH) secretion. Pheromones emitted by sexually mature males are thought to play a prominent role in this male effect. In the present study, we first aimed to clarify whether the male goat pheromone is effective in ewes. Seasonally anestrous St. Croix ewes were exposed to hair extracts derived from either intact or castrated (control) male Shiba goats. The male goat-hair extract significantly increased LH secretion compared to the control, suggesting that an interspecies action of the male pheromone occurs between sheep and goats. Using the male goat-hair extract as the pheromone source, we then aimed to clarify the neural pathway involved in the signal transduction of the male pheromone. Ewes were exposed to either the goat-hair extract or the control and sacrificed 2 hr after the exposure. Expression of c-Fos, a marker of neuronal activation, was immunohistochemically examined. The male goat-hair extract significantly increased the c-Fos expression compared to the control in regions of the vomeronasal system, such as the accessory olfactory bulb and medial amygdala, and the arcuate nucleus. The main olfactory bulb did not exhibit any significant increase in the c-Fos expression by the male goat-hair extract. This result suggests that the neural signal of the male pheromone is conveyed to the GnRH pulse generator through the activated regions in ewes.

Show MeSH
Related in: MedlinePlus