摘要
Background: Kisspeptin has been demonstrated to affect the attainment of puberty in multiple species, presumably through its actions on GnRH and LH. It has previously been found there is an increase in expression of hypothalamic in the rat and the monkey coincident with puberty. Whether a similar phenomenon occurs in the pig remains to be determined. The objectives of the current experiments were to determine 1) Plasma concentrations of estradiol-17β;2) Anterior pituitary gland concentrations of LH, IGF-I, kisspeptin, and anterior pituitary gland expression of LH-β and GnRH receptor;3) Mediobasal hypothalamus expression of Kiss1 and concentrations of kisspeptin during the peripubertal period in the gilt. Methods: Two experiments were performed, each with 25 crossbred gilts (151 d, 105 kg). Gilts were relocated and exposed to a mature boar beginning on d 1 and continuing throughout the experiments to naturally induce puberty. Gilts that stood immobile within 24 hours of slaughter were considered to have attained puberty. Plasma samples were collected on d 1, 3, and 7 of the first experiment and d 2, 4, 6, and 8 of the second experiment. Gilts were slaughtered on d 7 (experiment 1) or d 8 (experiment 2), when mediobasal hypothalamus (MBH), anterior pituitary glands (AP), and blood were collected. Relative expression of MBH Kiss1 and β-actin and AP GnRH receptor, LH-β, was determined using real-time reverse transcriptase PCR. Fold changes in relative expression were determined using the Relative Expression Software Tool. Hypothalamic and AP content of kisspeptin were determined by RIA and differences were determined using the GLIMMIX procedure of SAS. Results: Relative expression of Kiss1 was increased (P = 0.005) 2.2 fold in the gilts that had attained puberty in the first experiment, however, those that had attained puberty in the second were not different (P > 0.05) from gilts that had not. Relative expression of GnRH receptor was not different (P > 0.05) between treatments in both experiments. Relative expression of LH-β tended to be decreased (P = 0.09) 0.80 fold in gilts that attained puberty in the first experiment but was not different (P > 0.05) in gilts that attained puberty in the second experiment. AP concentrations of LH were not different (P > 0.05) between treatments in the first experiment and were decreased (P = 0.01) in gilts that attained puberty in the second experiment. AP concentrations of kisspeptin were not different (P > 0.05) in the first experiment but were increased (P = 0.04) in gilts that had attained puberty in the second experiment. MBH concentrations of kisspeptin were increased (P = 0.03) in gilts that had attained puberty in the first experiment but were not different (P > 0.05) between treatments in the second experiment. Conclusions: These data further support the role that MBH expression of Kiss1 and concentrations of kisspeptin and AP concentrations of kisspeptin fluctuate during the peripubertal period and may play a role in the attainment of puberty in the gilt.
Background: Kisspeptin has been demonstrated to affect the attainment of puberty in multiple species, presumably through its actions on GnRH and LH. It has previously been found there is an increase in expression of hypothalamic in the rat and the monkey coincident with puberty. Whether a similar phenomenon occurs in the pig remains to be determined. The objectives of the current experiments were to determine 1) Plasma concentrations of estradiol-17β;2) Anterior pituitary gland concentrations of LH, IGF-I, kisspeptin, and anterior pituitary gland expression of LH-β and GnRH receptor;3) Mediobasal hypothalamus expression of Kiss1 and concentrations of kisspeptin during the peripubertal period in the gilt. Methods: Two experiments were performed, each with 25 crossbred gilts (151 d, 105 kg). Gilts were relocated and exposed to a mature boar beginning on d 1 and continuing throughout the experiments to naturally induce puberty. Gilts that stood immobile within 24 hours of slaughter were considered to have attained puberty. Plasma samples were collected on d 1, 3, and 7 of the first experiment and d 2, 4, 6, and 8 of the second experiment. Gilts were slaughtered on d 7 (experiment 1) or d 8 (experiment 2), when mediobasal hypothalamus (MBH), anterior pituitary glands (AP), and blood were collected. Relative expression of MBH Kiss1 and β-actin and AP GnRH receptor, LH-β, was determined using real-time reverse transcriptase PCR. Fold changes in relative expression were determined using the Relative Expression Software Tool. Hypothalamic and AP content of kisspeptin were determined by RIA and differences were determined using the GLIMMIX procedure of SAS. Results: Relative expression of Kiss1 was increased (P = 0.005) 2.2 fold in the gilts that had attained puberty in the first experiment, however, those that had attained puberty in the second were not different (P > 0.05) from gilts that had not. Relative expression of GnRH receptor was not different (P > 0.05) between treatments in both experiments. Relative expression of LH-β tended to be decreased (P = 0.09) 0.80 fold in gilts that attained puberty in the first experiment but was not different (P > 0.05) in gilts that attained puberty in the second experiment. AP concentrations of LH were not different (P > 0.05) between treatments in the first experiment and were decreased (P = 0.01) in gilts that attained puberty in the second experiment. AP concentrations of kisspeptin were not different (P > 0.05) in the first experiment but were increased (P = 0.04) in gilts that had attained puberty in the second experiment. MBH concentrations of kisspeptin were increased (P = 0.03) in gilts that had attained puberty in the first experiment but were not different (P > 0.05) between treatments in the second experiment. Conclusions: These data further support the role that MBH expression of Kiss1 and concentrations of kisspeptin and AP concentrations of kisspeptin fluctuate during the peripubertal period and may play a role in the attainment of puberty in the gilt.
作者
Jeffrey Clapper
Eric Jolitz
LeAnn Hall
Waljit Dhillo
Jeffrey Clapper;Eric Jolitz;LeAnn Hall;Waljit Dhillo(Department of Animal Science, South Dakota State University, Brookings, SD, USA;Imperial College London at Hammersmith Campus, London, UK)
