Transgenic mice overexpressing des-acyl ghrelin show small phenotype.
Ghrelin, a 28-amino acid acylated peptide, displays strong GH-releasing activity in concert with GHRH. The fatty acid modification of ghrelin is essential for the actions, and des-acyl ghrelin, which lacks the modification, has been assumed to be devoid of biological effects. Some recent reports, however, indicate that des-acyl ghrelin has effects on cell proliferation and survival. In the present study, we generated two lines of transgenic mice bearing the preproghrelin gene under the control of chicken beta-actin promoter. Transgenic mice overexpressed des-acyl ghrelin in a wide variety of tissues, and plasma des-acyl ghrelin levels reached 10- and 44-fold of those in control mice. They exhibited lower body weights and shorter nose-to-anus lengths, compared with control mice. The serum GH levels tended to be lower, and the serum IGF-I levels were significantly lower in both male and female transgenic mice than control mice. The responses of GH to administered GHRH were normal, whereas those to administered ghrelin were reduced, especially in female transgenic mice, compared with control mice. These data suggest that overexpressed des-acyl ghrelin may modulate the GH-IGF-I axis and result in small phenotype in transgenic mice.
Ariyasu
Hiroyuki
H
Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan.
Takaya
Kazuhiko
K
Iwakura
Hiroshi
H
Hosoda
Hiroshi
H
Akamizu
Takashi
T
Arai
Yuji
Y
Kangawa
Kenji
K
Nakao
Kazuwa
K
D000818:Animals; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D054439:Ghrelin; D013006:Growth Hormone / Q000097:blood / Q000235:genetics / Q000378:metabolism; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology; D007031:Hypothalamus / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D007260:Infusion Pumps; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D009037:Motilin / Q000235:genetics; D009479:Neuropeptides / Q000378:metabolism / Q000502:physiology; D009929:Organ Size; D036361:Peptide Hormones / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D010641:Phenotype; D010902:Pituitary Gland / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013194:Staining and Labeling
D054439:Ghrelin; D009479:Neuropeptides; D036361:Peptide Hormones; D012333:RNA, Messenger; C422650:ghrelin, des-n-octanoyl; D009037:Motilin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone