dc.contributor.author |
Li, Fengxia |
en |
dc.contributor.author |
Liu, Karen |
en |
dc.contributor.author |
Wang, Ao |
en |
dc.contributor.author |
Harris, Paul |
en |
dc.contributor.author |
Vickers, Mark |
en |
dc.contributor.author |
Guan, Jian |
en |
dc.date.accessioned |
2019-09-29T21:44:08Z |
en |
dc.date.issued |
2019-08 |
en |
dc.identifier.issn |
0143-4179 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/47978 |
en |
dc.description.abstract |
Childhood metabolic disorders are associated with insulin-like growth factor (IGF)-1 deficiency, which can adversely affect brain development and function. As a neuropeptide, cyclic glycine-proline (cGP) improves IGF-1 function in brain and regulates IGF-1 bioavailability in plasma. Whether such a regulatory process mediates the neurotrophic effects of cGP remains unknown. This study examined the effects cGP treatment on synaptic expression and their association with IGF-1, IGF binding protein (IGFBP)-2 and cGP concentrations in the brain of rats with high fat diet (HFD)-induced obesity. Male rats received either a HFD or a standard chow diet (STD) from weaning and were then treated with either saline or cGP from 11 to 15 weeks of age. The concentrations of cGP, IGF-1 and IGFBP-2 were measured in the brain tissues using ELISA and HPLC-MS. The expressions of synaptic markers were evaluated in the hippocampus, hypothalamus and striatum using immunohistochemical staining. Compared to the STD group, IGF-1 and IGFBP-2, but not cGP concentrations, were lower in the HFD groups. The expression of hippocampal synaptophysin, glutamate receptor-1, GFAP and striatal tyrosine-hydroxylase were also reduced in the HFD groups. While treatment did not alter tissue IGF-1, cGP administration that increased the concentration of cGP in brain tissues, normalized the expression of synaptophysin, GFAP and tyrosine-hydroxylase, but not glutamate receptor-1. IGF-1 concentration in brain tissues correlated with the expression of all synaptic markers. HFD feeding reduced synaptic expression and tissue IGF-1 in brains which were closely associated, thus suggesting IGF-1 in the brain is largely bioavailable. Without increasing IGF-1 in the brain, administration of cGP normalized synaptic expression, possibly be mediated through increasing bioavailable IGF-1, but further studies are required to confirm this. |
en |
dc.format.medium |
Print-Electronic |
en |
dc.language |
eng |
en |
dc.relation.ispartofseries |
Neuropeptides |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.subject |
Animals |
en |
dc.subject |
Rats, Sprague-Dawley |
en |
dc.subject |
Obesity |
en |
dc.subject |
Disease Models, Animal |
en |
dc.subject |
Peptides, Cyclic |
en |
dc.subject |
Insulin-Like Growth Factor I |
en |
dc.subject |
Synaptophysin |
en |
dc.subject |
Male |
en |
dc.subject |
Diet, High-Fat |
en |
dc.title |
Cyclic glycine-proline administration normalizes high-fat diet-induced synaptophysin expression in obese rats. |
en |
dc.type |
Journal Article |
en |
dc.identifier.doi |
10.1016/j.npep.2019.05.006 |
en |
pubs.begin-page |
101935 |
en |
pubs.volume |
76 |
en |
dc.rights.holder |
Copyright: The author |
en |
pubs.publication-status |
Published |
en |
dc.rights.accessrights |
http://purl.org/eprint/accessRights/RestrictedAccess |
en |
pubs.subtype |
Journal Article |
en |
pubs.elements-id |
773769 |
en |
pubs.org-id |
Liggins Institute |
en |
pubs.org-id |
Medical and Health Sciences |
en |
pubs.org-id |
Medical Sciences |
en |
pubs.org-id |
Pharmacology |
en |
pubs.org-id |
Science |
en |
pubs.org-id |
Biological Sciences |
en |
pubs.org-id |
Science Research |
en |
pubs.org-id |
Maurice Wilkins Centre (2010-2014) |
en |
dc.identifier.eissn |
1532-2785 |
en |
pubs.record-created-at-source-date |
2019-06-01 |
en |
pubs.dimensions-id |
31146894 |
en |