Submitted to: Reproduction
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/1/2008
Publication Date: 7/1/2008
Publication URL: www.reproduction-online.org
Citation: Lents, C.A., Heidorn, N.L., Barb, C.R., Ford, J.J. 2008. Central and peripheral administration of kisspeptin activates gonadotropin but not somatotropin secretion in prepubertal gilts. Reproduction. 135:879-887. Interpretive Summary: In pigs, infertility is a major cause of decreased numbers of animals marketed per year, which leads to reduced income and increased economic instability for producers. One of the primary reasons for infertility is that animals fail to exhibit estrous cycles (anestrous) and ovulate. The newly identified neuropeptide, kisspeptin, has been implicated as a potent stimulant of pituitary luteinizing hormone (LH) secretion, necessary for ovulation. It was demonstrated that administration of kisspeptin into the lateral ventricle of the brain stimulated LH and follicle stimulating hormone (FSH) secretion but not growth hormone (GH) in the prepubertal gilt. Peripheral administration of kisspeptin increased serum concentrations of LH but not FSH or GH. These data illustrate that kisspeptin can activate the brain-pituitary axis and maybe part of an important mechanism regulating activation of the GnRH, brain hormone necessary for LH release, neuronal system and initiating onset of puberty in swine.
Technical Abstract: The role that kisspeptin might have in regulating the onset of puberty in large domestic animals is unknown. We tested the hypothesis that either central or peripheral infusion of kisspeptin would stimulate gonadotropin and growth hormone secretion in prepubertal gilts. In experiment 1, prepubertal gilts were fitted with intracerebralventricular (ICV) cannula and indwelling jugular catheters. Animals were randomly assigned to receive either 10 or 100 ug of kisspeptin-10 or saline control. In experiment 2, prepubertal gilts, fitted with indwelling jugular catheters, randomly received 1, 2.5 or 5 mg of Kisspeptin-10 or saline control infusion intravenously. Serial blood samples were collected every 15 min for 3 h before and 5 h after infusions, and serum concentrations of LH, FSH, and GH were determined. Mean concentrations of LH and FSH remained at basal levels for control animals but were increased (P < 0.001) for animals receiving ICV infusion of kisspeptin. Area under the LH and FSH curves following ICV infusion of kisspeptin increased (P < 0.001) in a dose dependent manner. Concentrations of GH were unaffected by ICV treatment. Peripheral administration of kisspeptin increased (P < 0.05) serum concentrations of LH but not FSH or GH. Area under the LH curve following IV infusion was similar for doses of kisspeptin. Thus kisspeptin can activate gonadotropic but not somatoropic hormone secretion in prepubertal gilts. The present data support the concept that kisspeptin plays a role in the mechanism involved in initiating puberty in swine.