TY - JOUR
T1 - Novel neuropeptides related to frog growth hormone-releasing peptide
T2 - Isolation, sequence, and functional analysis
AU - Ukena, Kazuyoshi
AU - Koda, Aya
AU - Yamamoto, Kazutoshi
AU - Kobayashi, Tetsuya
AU - Iwakoshi-Ukena, Eiko
AU - Minakata, Hiroyuki
AU - Kikuyama, Sakae
AU - Tsutsui, Kazuyoshi
PY - 2003/9/1
Y1 - 2003/9/1
N2 - We previously identified in the bullfrog a novel hypothalamic RFamide peptide (SLKPAANLPLRF-NH2) that stimulated GH release in vitro and in vivo and therefore was designated frog GH-releasing peptide (fGRP). Molecular cloning of cDNA encoding the deduced fGRP precursor polypeptide further revealed that it encodes fGRP and its related peptides (fGRP-RP-1, -RP-2, and -RP-3). In this study immunoaffinity purification using the antibody against fGRP was therefore conducted to determine whether these three putative fGRP-RPs exist as mature endogenous ligands in the frog brain. The mass peaks of the isolated immunoreactive substances were detected at 535.78, 1034.14, and 1079.71 m/z ([M+2H]2+), and their sequences, SIPNLPQRF-NH 2, YLSGKTKVQSMANLPQRF-NH2, and AQYTNHFVHSLDTLPLRF-NH 2, were revealed by the fragmentation, showing mature forms encoded in the cDNA sequences of fGRP-RP-1, -RP-2, and -RP-3, respectively. All of these fGRP-RPs contained a C-terminal -LPXRF-NH2 (X = L or Q) sequence, such as fGRP. This study further analyzed hypophysiotropic activities of the identified endogenous fGRP-RPs. Only fGRP-RP-2 stimulated, in a dose-related way, the release of PRL from cultured frog pituitary cells; its threshold concentration ranged from less than 10-7 M. A similar stimulatory action of fGRP-RP-2 on GH release was evident. It was ascertained that fGRP-RP-2 was also effective in elevating the circulating GH and PRL levels when administered systemically. In contrast, fGRP-RPs did not have any appreciable effect on the release of gonadotropins. Thus, fGRP-RP-2 may act as a novel hypothalamic factor on the frog pituitary to stimulate the release of GH and PRL.
AB - We previously identified in the bullfrog a novel hypothalamic RFamide peptide (SLKPAANLPLRF-NH2) that stimulated GH release in vitro and in vivo and therefore was designated frog GH-releasing peptide (fGRP). Molecular cloning of cDNA encoding the deduced fGRP precursor polypeptide further revealed that it encodes fGRP and its related peptides (fGRP-RP-1, -RP-2, and -RP-3). In this study immunoaffinity purification using the antibody against fGRP was therefore conducted to determine whether these three putative fGRP-RPs exist as mature endogenous ligands in the frog brain. The mass peaks of the isolated immunoreactive substances were detected at 535.78, 1034.14, and 1079.71 m/z ([M+2H]2+), and their sequences, SIPNLPQRF-NH 2, YLSGKTKVQSMANLPQRF-NH2, and AQYTNHFVHSLDTLPLRF-NH 2, were revealed by the fragmentation, showing mature forms encoded in the cDNA sequences of fGRP-RP-1, -RP-2, and -RP-3, respectively. All of these fGRP-RPs contained a C-terminal -LPXRF-NH2 (X = L or Q) sequence, such as fGRP. This study further analyzed hypophysiotropic activities of the identified endogenous fGRP-RPs. Only fGRP-RP-2 stimulated, in a dose-related way, the release of PRL from cultured frog pituitary cells; its threshold concentration ranged from less than 10-7 M. A similar stimulatory action of fGRP-RP-2 on GH release was evident. It was ascertained that fGRP-RP-2 was also effective in elevating the circulating GH and PRL levels when administered systemically. In contrast, fGRP-RPs did not have any appreciable effect on the release of gonadotropins. Thus, fGRP-RP-2 may act as a novel hypothalamic factor on the frog pituitary to stimulate the release of GH and PRL.
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U2 - 10.1210/en.2003-0359
DO - 10.1210/en.2003-0359
M3 - Article
C2 - 12933661
AN - SCOPUS:0042922570
SN - 0013-7227
VL - 144
SP - 3879
EP - 3884
JO - Endocrinology
JF - Endocrinology
IS - 9
ER -
