Limits...
Kisspeptin signaling is required for the luteinizing hormone response in anestrous ewes following the introduction of males.

De Bond JA, Li Q, Millar RP, Clarke IJ, Smith JT - PLoS ONE (2013)

Bottom Line: Introduction of a male led to elevated mean LH levels, due to increased LH pulse amplitude and pulse frequency in females, when compared to females not exposed to a male.Brains were collected after the male effect stimulus and we observed an increase in the percentage of kisspeptin neurons co-expressing Fos, by immunohistochemistry.We conclude that introduction of male sheep to seasonally anestrous female sheep activates kisspeptin neurons and other cells in the hypothalamus, leading to increased GnRH/LH secretion.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Monash University, Melbourne, Victoria, Australia.

ABSTRACT
The introduction of a novel male stimulates the hypothalamic-pituitary-gonadal axis of female sheep during seasonal anestrus, leading to the resumption of follicle maturation and ovulation. How this pheromone cue activates pulsatile secretion of gonadotropin releasing hormone (GnRH)/luteinizing hormone (LH) is unknown. We hypothesised that pheromones activate kisspeptin neurons, the product of which is critical for the stimulation of GnRH neurons and fertility. During the non-breeding season, female sheep were exposed to novel males and blood samples collected for analysis of plasma LH profiles. Females without exposure to males served as controls. In addition, one hour before male exposure, a kisspeptin antagonist (P-271) or vehicle was infused into the lateral ventricle and continued for the entire period of male exposure. Introduction of a male led to elevated mean LH levels, due to increased LH pulse amplitude and pulse frequency in females, when compared to females not exposed to a male. Infusion of P-271 abolished this effect of male exposure. Brains were collected after the male effect stimulus and we observed an increase in the percentage of kisspeptin neurons co-expressing Fos, by immunohistochemistry. In addition, the per-cell expression of Kiss1 mRNA was increased in the rostral and mid (but not the caudal) arcuate nucleus (ARC) after male exposure in both aCSF and P-271 treated ewes, but the per-cell content of neurokinin B mRNA was decreased. There was also a generalized increase in Fos positive cells in the rostral and mid ARC as well as the ventromedial hypothalamus of females exposed to males. We conclude that introduction of male sheep to seasonally anestrous female sheep activates kisspeptin neurons and other cells in the hypothalamus, leading to increased GnRH/LH secretion.

Show MeSH

Related in: MedlinePlus

Male exposure in ewes increased the content of Kiss1 mRNA in the rostral ARC.A, Representative dark-field photomicrographs of the rostral ARC showing Kiss1 mRNA expressing neurons (as indicated by the presence of silver grain clusters). 3V, Third ventricle. Scale bar, 200 µm. B–C, Kiss1 mRNA content per cell was significantly greater in anestrous ewes exposed to males compared to non-exposed controls in the rostral ARC (B). P-271 had no effect on Kiss1 mRNA content. Data are the mean ± SEM, *P<0.05, n = 4 per group.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3585258&req=5

pone-0057972-g006: Male exposure in ewes increased the content of Kiss1 mRNA in the rostral ARC.A, Representative dark-field photomicrographs of the rostral ARC showing Kiss1 mRNA expressing neurons (as indicated by the presence of silver grain clusters). 3V, Third ventricle. Scale bar, 200 µm. B–C, Kiss1 mRNA content per cell was significantly greater in anestrous ewes exposed to males compared to non-exposed controls in the rostral ARC (B). P-271 had no effect on Kiss1 mRNA content. Data are the mean ± SEM, *P<0.05, n = 4 per group.

Mentions: Cells expressing Kiss1 mRNA were identifiable in the ARC (Figure 6A). The number of Kiss1 expressing cells was similar in all groups (Figure 6B–D). In the rostral ARC, the Kiss1 mRNA content per cell was 3-fold greater (P<0.05, Figure 6E) in ewes exposed to a male compared to control ewes. P-271 treatment did not alter this response to male exposure. Similar trends in the mid and caudal ARC were not statistically significant (Figure 6F, G).


Kisspeptin signaling is required for the luteinizing hormone response in anestrous ewes following the introduction of males.

De Bond JA, Li Q, Millar RP, Clarke IJ, Smith JT - PLoS ONE (2013)

Male exposure in ewes increased the content of Kiss1 mRNA in the rostral ARC.A, Representative dark-field photomicrographs of the rostral ARC showing Kiss1 mRNA expressing neurons (as indicated by the presence of silver grain clusters). 3V, Third ventricle. Scale bar, 200 µm. B–C, Kiss1 mRNA content per cell was significantly greater in anestrous ewes exposed to males compared to non-exposed controls in the rostral ARC (B). P-271 had no effect on Kiss1 mRNA content. Data are the mean ± SEM, *P<0.05, n = 4 per group.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585258&req=5

pone-0057972-g006: Male exposure in ewes increased the content of Kiss1 mRNA in the rostral ARC.A, Representative dark-field photomicrographs of the rostral ARC showing Kiss1 mRNA expressing neurons (as indicated by the presence of silver grain clusters). 3V, Third ventricle. Scale bar, 200 µm. B–C, Kiss1 mRNA content per cell was significantly greater in anestrous ewes exposed to males compared to non-exposed controls in the rostral ARC (B). P-271 had no effect on Kiss1 mRNA content. Data are the mean ± SEM, *P<0.05, n = 4 per group.
Mentions: Cells expressing Kiss1 mRNA were identifiable in the ARC (Figure 6A). The number of Kiss1 expressing cells was similar in all groups (Figure 6B–D). In the rostral ARC, the Kiss1 mRNA content per cell was 3-fold greater (P<0.05, Figure 6E) in ewes exposed to a male compared to control ewes. P-271 treatment did not alter this response to male exposure. Similar trends in the mid and caudal ARC were not statistically significant (Figure 6F, G).

Bottom Line: Introduction of a male led to elevated mean LH levels, due to increased LH pulse amplitude and pulse frequency in females, when compared to females not exposed to a male.Brains were collected after the male effect stimulus and we observed an increase in the percentage of kisspeptin neurons co-expressing Fos, by immunohistochemistry.We conclude that introduction of male sheep to seasonally anestrous female sheep activates kisspeptin neurons and other cells in the hypothalamus, leading to increased GnRH/LH secretion.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Monash University, Melbourne, Victoria, Australia.

ABSTRACT
The introduction of a novel male stimulates the hypothalamic-pituitary-gonadal axis of female sheep during seasonal anestrus, leading to the resumption of follicle maturation and ovulation. How this pheromone cue activates pulsatile secretion of gonadotropin releasing hormone (GnRH)/luteinizing hormone (LH) is unknown. We hypothesised that pheromones activate kisspeptin neurons, the product of which is critical for the stimulation of GnRH neurons and fertility. During the non-breeding season, female sheep were exposed to novel males and blood samples collected for analysis of plasma LH profiles. Females without exposure to males served as controls. In addition, one hour before male exposure, a kisspeptin antagonist (P-271) or vehicle was infused into the lateral ventricle and continued for the entire period of male exposure. Introduction of a male led to elevated mean LH levels, due to increased LH pulse amplitude and pulse frequency in females, when compared to females not exposed to a male. Infusion of P-271 abolished this effect of male exposure. Brains were collected after the male effect stimulus and we observed an increase in the percentage of kisspeptin neurons co-expressing Fos, by immunohistochemistry. In addition, the per-cell expression of Kiss1 mRNA was increased in the rostral and mid (but not the caudal) arcuate nucleus (ARC) after male exposure in both aCSF and P-271 treated ewes, but the per-cell content of neurokinin B mRNA was decreased. There was also a generalized increase in Fos positive cells in the rostral and mid ARC as well as the ventromedial hypothalamus of females exposed to males. We conclude that introduction of male sheep to seasonally anestrous female sheep activates kisspeptin neurons and other cells in the hypothalamus, leading to increased GnRH/LH secretion.

Show MeSH
Related in: MedlinePlus