Seasonal and Cyclical Change in the Luteinizing Hormone Response to Kisspeptin in the Ewe

Smith, Jeremy Troy; Saleh, Sofie Nh; Clarke, I. J.

doi:10.1159/000227806

Cited by 45 publications

(40 citation statements)

References 97 publications

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“…Therefore, there is evidence of an action of kisspeptin on isolated pituitary cells [10]. However in the whole animal, when the lack of an effect of KP-10 on basal [13,14,44] and GHRH-stimulated GH are taken into consideration (fig. 1), these data suggest that any direct pituitary effect of kisspeptin to increase plasma GH concentrations in the ruminant remains to be determined.…”

Section: Discussionmentioning

confidence: 99%

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Interaction of Kisspeptin and the Somatotropic Axis

et al. 2010

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Kisspeptin, a regulator of gonadotropin-releasing hormone, has been hypothesized as an integrator of nutrition and hormones critical to metabolism and the regulation of reproduction. Growth hormone (GH) is necessary for optimal reproduction and recent evidence suggests that its secretion may be influenced by kisspeptin. The objectives of this study were to determine whether the effect of kisspeptin to stimulate GH release is due to an interaction with growth hormone-releasing hormone (GHRH) or somatostatin (SS), or an effect at the hypothalamus. Intravenous injection and infusion of kisspeptin [500 pmol/kg BW (650 ng/kg)/h × 5 h] to cows (n = 5) increased serum concentrations of luteinizing hormone (LH) but not GH. Pretreatment with kisspeptin injection and infusion in cows (n = 5) reduced the stimulatory effect of GHRH (0.05 µg/kg BW) on GH secretion. However, the magnitude of the GH response to GHRH (assessed by incremental AUC) was not affected by kisspeptin. In these same cows, administration of kisspeptin prevented the increase in GH induced by SS infusion (0.5 µg/kg BW/ h × 1.5 h) withdrawal. Peripheral administration of kisspeptin [200 and 1,000 pmol/kg BW (260 and 1,300 ng/kg)] increased serum concentrations of LH but not GH in ewes (n = 8). However, concentrations of GH were stimulated by central kisspeptin treatment [100 and 200 pmol/kg BW (130 and 260 ng/kg)] in ewes. In addition to activating the gonadotropic axis, kisspeptin can activate the somatotropic axis in ruminants. Present data support the concept of a central site of action for this effect.

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Section: Discussionmentioning

confidence: 99%

“…The i.v. injection of KP-10 produces an immediate and potent stimulus to LH [13,28], but not GH [13,15,44], release. However, similar doses of kisspeptin injected ICV produce a release of both GH and LH.…”

Section: Discussionmentioning

confidence: 99%

Interaction of Kisspeptin and the Somatotropic Axis

et al. 2010

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“…Although pubertal activation of pulsatile GNRH release has been well characterized (Wildt et al 1980, Kinder et al 1995, the mechanisms and neuronal pathways leading to increased frequency of GNRH release during the peripubertal period remain unclear. Kisspeptin, a peptide with potent stimulatory effects on the release of GNRH and LH (Matsui et al 2004, Messager et al 2005, Lents et al 2008, Magee et al 2009, Smith et al 2009b, plays a critical role. Kisspeptin (d'Anglemont de Tassigny et al 2007, Lapatto et al 2007) and its receptor (de Roux et al 2003, Seminara et al 2003 are essential for normal onset of puberty.…”

Section: Introductionmentioning

confidence: 99%

Kisspeptin activates the hypothalamic–adenohypophyseal–gonadal axis in prepubertal ewe lambs

Redmond¹,

Macedo²,

Velez³

et al. 2011

Reproduction

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The onset of puberty in mammals involves an increase in the pulsatile release of GNRH and LH. The KISS1 gene is essential for pubertal development, and its product, kisspeptin, stimulates the release of LH. The objective of this study was to determine the effects of kisspeptin in the hypothalamic-adenohypophyseal-gonadal axis of prepubertal ewe lambs. Ewe lambs (28 weeks of age) were treated intravenously with saline (control, nZ6) or kisspeptin (20 mg kisspeptin; nZ6) every hour for 24 h. Kisspeptin stimulated pulse-like release of LH within 15 min following injections, and increased the frequency and amplitude of LH pulses, and mean circulating concentrations of LH and estradiol. A surge-like release of LH was observed in four kisspeptin-treated lambs beginning 17 h after the onset of treatment, and all four lambs had elevated circulating concentrations of progesterone within 5 days post-treatment. However, circulating concentrations of progesterone decreased within 2 days after the initial rise in three of the four ewe lambs, indicating that induced luteal activity was of short duration. The proportion of lambs that were pubertal (defined by circulating concentrations of progesterone above 1 ng/ml for at least 7 days) by 35 weeks of age (8/11) and the mean age at puberty (32G1 weeks) for those reaching puberty within the experimental period did not differ between treatments. Results support a role for kisspeptin in the activation of the hypothalamic-adenohypophyseal axis leading to the onset of puberty in ewe lambs.

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“…Fascinatingly, single nucleotide polymorphisms in the Kiss1 gene were associated with increased litter size in goats (An et al, 2013). The LH response to Kp-10 was greater in the late-follicular phase when matched with the luteal phase during the breeding season (Smith et al, 2011), and the influence of Kp-10 on LH but not FSH, secretion, was more during the anoestrous season than in the luteal phase during the breeding season (Smith et al, 2009a).…”

Section: Kisspeptin Action On Lh and Gonadotropinmentioning

confidence: 88%