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 decreased the content of Tac2 mRNA in the rostral ARC.A, Representative bright-field photomicrographs showing neurons in the rostral ARC containing Kiss1 mRNA (grey) and Tac2 mRNA (as indicated by the presence of silver grain clusters). 3V, Third ventricle. Scale bar, 50 µm. B–C, Tac2 mRNA content per Kiss1 cell was significantly reduced in anestrous ewes exposed to males compared to non-exposed controls in the rostral ARC (B). P-271 had no effect on Tac2 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-g007: Male exposure in ewes decreased the content of Tac2 mRNA in the rostral ARC.A, Representative bright-field photomicrographs showing neurons in the rostral ARC containing Kiss1 mRNA (grey) and Tac2 mRNA (as indicated by the presence of silver grain clusters). 3V, Third ventricle. Scale bar, 50 µm. B–C, Tac2 mRNA content per Kiss1 cell was significantly reduced in anestrous ewes exposed to males compared to non-exposed controls in the rostral ARC (B). P-271 had no effect on Tac2 mRNA content. Data are the mean ± SEM, *P<0.05, n = 4 per group.

Mentions: Tac2 mRNA expression was readily detectable in virtually all Kiss1 mRNA neurons in the ARC (Figure 7A). The per Kiss1 cell content of Tac2 mRNA was 36% lower in ewes exposed to males compared to controls (P<0.05, Figure 7B). Kisspeptin antagonist (P-271) treatment did not alter this male exposure effect. The per Kiss1 cell content of Tac2 mRNA in the mid and caudal ARC did not differ with male exposure or treatment with P-271.


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 decreased the content of Tac2 mRNA in the rostral ARC.A, Representative bright-field photomicrographs showing neurons in the rostral ARC containing Kiss1 mRNA (grey) and Tac2 mRNA (as indicated by the presence of silver grain clusters). 3V, Third ventricle. Scale bar, 50 µm. B–C, Tac2 mRNA content per Kiss1 cell was significantly reduced in anestrous ewes exposed to males compared to non-exposed controls in the rostral ARC (B). P-271 had no effect on Tac2 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-g007: Male exposure in ewes decreased the content of Tac2 mRNA in the rostral ARC.A, Representative bright-field photomicrographs showing neurons in the rostral ARC containing Kiss1 mRNA (grey) and Tac2 mRNA (as indicated by the presence of silver grain clusters). 3V, Third ventricle. Scale bar, 50 µm. B–C, Tac2 mRNA content per Kiss1 cell was significantly reduced in anestrous ewes exposed to males compared to non-exposed controls in the rostral ARC (B). P-271 had no effect on Tac2 mRNA content. Data are the mean ± SEM, *P<0.05, n = 4 per group.
Mentions: Tac2 mRNA expression was readily detectable in virtually all Kiss1 mRNA neurons in the ARC (Figure 7A). The per Kiss1 cell content of Tac2 mRNA was 36% lower in ewes exposed to males compared to controls (P<0.05, Figure 7B). Kisspeptin antagonist (P-271) treatment did not alter this male exposure effect. The per Kiss1 cell content of Tac2 mRNA in the mid and caudal ARC did not differ with male exposure or treatment with P-271.

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