title: Potencies of centrally- or peripherally-injected full-length kisspeptin or its C-terminal decapeptide on LH release in intact male rats.
abstract: The aim of the present study was to compare the effects of full-length rat kisspeptin (rKp-52) with C-terminal decapeptide (Kp-10) of rat or human kisspeptin on LH release in intact male rats. Plasma LH profiles were determined by frequent blood sampling at 6-min intervals for 3 h after central or peripheral injection of kisspeptins. Intracerebroventricular (icv) injection of rKp-52 (0.1 nmol) induced a gradual increase in the plasma LH level, which remained high for the rest of the sampling period. On the other hand, icv injection of rKp-10 did not increase the plasma LH level at the same dose (0.1 nmol). A 10-times higher dose (1 nmol) of rKp-10 and hKp-10 increased the plasma LH level, but the increase was lower than that of rKp-52 icv injection. Intravenous (iv) injection of kisspeptins also stimulated LH release at 10 or 100 nmol/kg. In rKp-52 (10 nmol/kg)-treated animals, the plasma LH level reached a peak within 30 min and remained high until 60 min postinjection. The rKp-10- and hKp-10-injected animals showed a more rapid decline in plasma LH level after the peak found at around 30 min after the injections at both middle (10 nmol/kg) and high (100 nmol/kg) doses. The present study indicates that full-length kisspeptin is more effective in stimulating LH release compared with Kp-10 in male rats. The difference in LH-releasing activity may be the result of a difference in degradation of the peptides, but it is still worth determining whether an active domain other than the C-terminal decapeptide is present in full-length kisspeptin.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
authors.forename: Vutha
authors.initials: V
authors.lastname: Pheng
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Uenoyama
authors.forename: Tamami
authors.initials: T
authors.lastname: Homma
authors.forename: Yoko
authors.initials: Y
authors.lastname: Inamoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Takase
authors.forename: Kumiko
authors.initials: K
authors.lastname: Yoshizawa-Kumagaye
authors.forename: Shuji
authors.initials: S
authors.lastname: Isaka
authors.forename: Takushi X
authors.initials: TX
authors.lastname: Watanabe
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ohkura
authors.forename: Junko
authors.initials: J
authors.lastname: Tomikawa
authors.forename: Kei-ichiro
authors.initials: K
authors.lastname: Maeda
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tsukamura
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D059648:Kisspeptins; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D010455:Peptides / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D000074502:Receptors, Kisspeptin-1; D017386:Sequence Homology, Amino Acid
chemical_list: C491406:Kiss1 protein, rat; C492247:Kiss1r protein, rat; D059648:Kisspeptins; D010455:Peptides; D011506:Proteins; D043562:Receptors, G-Protein-Coupled; D000074502:Receptors, Kisspeptin-1; D007986:Luteinizing Hormone