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Glucagon-like peptide-1 (GLP-1) increases in plasma and colon tissue prior to estrus and circulating levels change with increasing age in reproductively competent Wistar rats

Johnson, Michelle L.; Saffrey, M. Jill and Taylor, Victoria J. (2017). Glucagon-like peptide-1 (GLP-1) increases in plasma and colon tissue prior to estrus and circulating levels change with increasing age in reproductively competent Wistar rats. Peptides (Early Access).

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DOI (Digital Object Identifier) Link: https://doi.org/10.1016/j.peptides.2017.02.010
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Abstract

There is a well-documented association between cyclic changes to food intake and the changing ovarian hormone levels of the reproductive cycle in female mammals. Limited research on appetite-controlling gastrointestinal peptides has taken place in females, simply because regular reproductive changes in steroid hormones present additional experimental factors to account for. This study focussed directly on the roles that gastrointestinal-secreted peptides may have in these reported, naturally occurring, changes to food intake during the rodent estrous cycle and aimed to determine whether peripheral changes occurred in the anorexigenic (appetite-reducing) hormones peptide-YY (PYY) and glucagon-like peptide-1 (GLP-1) in female Wistar rats (32-44 weeks of age). Total forms of each peptide were measured in matched fed and fasted plasma and descending colon tissue samples for each animal during the dark (feeding) phase. PYY concentrations did not significantly change between defined cycle stages, in either plasma or tissue samples. GLP-1 concentrations in fed plasma and descending colon tissue were significantly increased during proestrus, just prior to a significant reduction in fasted stomach contents at estrus, suggesting increased satiety and reduced food intake at this stage of the cycle. Increased proestrus GLP-1 concentrations could contribute to the reported reduction in food intake during estrus and may also have biological importance in providing the optimal nutritional and metabolic environment for gametes at the potential point of conception. Additional analysis of the findings demonstrated significant interactions of ovarian cycle stage and fed/fasted status with age on GLP-1, but not PYY plasma concentrations. Slightly older females had reduced fed plasma GLP-1 suggesting that a relaxation of regulatory control of this incretin hormone may also take place with increasing age in reproductively competent females.

Item Type: Journal Item
Copyright Holders: 2017 Elsevier
ISSN: 0196-9781
Project Funding Details:
Funded Project NameProject IDFunding Body
Not SetNot SetThe Open University (OU)
Keywords: estrous cycle; ovarian cycle; appetite; gut peptides; GLP-1; PYY; satiety
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Life, Health and Chemical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Interdisciplinary Research Centre: Biomedical Research Network (BRN)
Item ID: 48674
Depositing User: Victoria Taylor
Date Deposited: 23 Feb 2017 16:01
Last Modified: 24 Feb 2017 19:25
URI: http://oro.open.ac.uk/id/eprint/48674
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