Reproduction in Domestic Animals

176 A Caraty and I FranceschiniFig. 5. LH secretion and ensuingovulation in ewes treated duringthe non-breeding season with anintravenous infusion of kisspeptin(20 lg ⁄ h for 48 h). The upperpanels show two examples of plasmaLH levels in kisspeptin-infusedewes, indicating that the treatmentled to increased secretion but thepreovulatory surge did not occuruntil 25 h later. This strongly suggeststhat the infusion initiated anartificial follicular phase and thatthe increased oestrogen resultingfrom this activated a positivefeedback response. The experimentwas repeated in France and inAustralia with similar results.Approximately 80% of the ewestreated with kisspeptin ovulated, asevidenced by resulting corporalutea on the ovaries. Adapted fromCaraty et al. (2007)of using kisspeptin for the control of the gonadotropinaxis provides hope for resolving all fertility problems.Who knows if this is the end of the story, or perhaps anew molecule activating kisspeptin might be discoveredin another 30 years’ time!ReferencesBlache D, Fabre-Nys CJ, Venier G, 1991: Ventromedialhypothalamus as a target for oestradiol action on proceptivity,receptivity and luteinizing hormone surge of the ewe.Brain Res 546, 241–249.Caraty A, Fabre-Nys C, Delaleu B, Locatelli A, Bruneau G,Karsch FJ, Herbison A, 1998: Evidence that the mediobasalhypothalamus is the primary site of action of estradiol ininducing the preovulatory gonadotropin releasing hormonesurge in the ewe. Endocrinology 139, 1752–1760.Caraty A, Smith JT, Lomet D, Ben Said S, Morrissey A,Cognie J, Doughton B, Baril G, Briant C, Clarke IJ, 2007:Kisspeptin synchronizes preovulatory surges in cyclical ewesand causes ovulation in seasonally acyclic ewes. Endocrinology148, 5258–5267.Clarke IJ, Cummins JT, Jenkin M, Phillips DJ, 1989: Theoestrogen-induced surge of LH requires a ‘signal’ pattern ofgonadotrophin-releasing hormone input to the pituitarygland in the ewe. J Endocrinol 122, 127–134.Clarkson J, Herbison AE, 2006: Postnatal development ofkisspeptin neurons in mouse hypothalamus; sexual dimorphismand projections to gonadotropin-releasing hormoneneurons. Endocrinology 147, 5817–5825.Dhillo WS, Chaudhri OB, Patterson M, Thompson EL,Murphy KG, Badman MK, McGowan BM, Amber V,Patel S, Ghatei MA, Bloom SR, 2005: Kisspeptin-54stimulates the hypothalamic-pituitary gonadal axis inhuman males. J Clin Endocrinol Metab 90, 6609–6615.Dhillo WS, Chaudhri OB, Thompson EL, Murphy KG,Patterson M, Ramachandran R, Nijher GK, Amber V,Kokkinos A, Donaldson M, Ghatei MA, Bloom SR, 2007:Kisspeptin-54 stimulates gonadotropin release mostpotently during the preovulatory phase of the menstrualcycle in women. J Clin Endocrinol Metab 92, 3958–3966.Dungan HM, Gottsch ML, Zeng H, Gragerov A, BergmannJE, Vassilatis DK, Clifton DK, Steiner RA, 2007: The roleof kisspeptin-GPR54 signaling in the tonic regulation andsurge release of gonadotropin-releasing hormone ⁄ luteinizinghormone. J Neurosci 27, 12088–12095.Estrada KM, Clay CM, Pompolo S, Smith JT, Clarke IJ, 2006:Elevated Kiss-1 expression in the arcuate nucleus prior tothe cyclic preovulatory gonadotropin-releasing hormone ⁄luteinising hormone surge in the ewe suggests a stimulatoryrole for kisspeptin in oestrogen-positive feedback. J Neuroendocrinol18, 139–149.Franceschini I, Lomet D, Cateau M, Delsol G, Tillet Y,Caraty A, 2006: Kisspeptin immunoreactive cells of theovine preoptic area and arcuate nucleus co-express estrogenreceptor alpha. Neurosci Lett 401, 225–230.Gottsch ML, Cunningham MJ, Smith JT, Popa SM, AcohidoBV, Crowley WF, Seminara S, Clifton DK, Steiner RA,2004: A role for kisspeptins in the regulation of gonadotropinsecretion in the mouse. Endocrinology 145, 4073–4077.Ó 2008 The Authors. Journal compilation Ó 2008 Blackwell Verlag