Blockade of actions from only one of the two L-cell hormones, GLP-1 and PYY, resulted in concomitant increased secretion of the other, probably explaining the absent effect on food intake on these experimental days. Combined blockade of GLP-1 and PYY actions increased food intake after RYGB, supporting that these hormones have a role in decreased food intake postoperatively.
Gut endocrine cells are generally thought to have distinct localization and secretory products. Recent studies suggested that the cells are highly related and have potential to express more than one hormone. We studied the coexpression and cosecretion of gut hormones in separate segments of rat small intestine. We measured secretion of glucagon-like peptide-1 (GLP-1), peptide YY (PYY), neurotensin, glucose-dependent insulinotropic polypeptide (GIP), and cholecystokinin (CCK) from proximal and distal half of the small intestine, isolated from male rats and perfused ex vivo. Hormone secretion was stimulated by bombesin, the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine, and peptones. Furthermore, tissue samples collected along the intestine were analyzed for expression, hormone content, and cell densities including colocalization. Most hormones responded to all three stimuli (but no GIP response to bombesin). GLP-1 secretion was similar from proximal and distal intestine, whereas PYY was secreted only from the distal half. CCK and GIP were mainly secreted proximally, whereas neurotensin was equally secreted from both parts. Cell densities, hormone concentrations, and expression patterns were generally parallel, with increasing values distally for GLP-1 and PYY, an exclusively proximal pattern for CCK, even distribution for neurotensin and GIP except for the most distal segments. PYY nearly always colocalized with GLP-1. Approximately 20% of GLP-1 cells colocalized with CCK and neurotensin, whereas GLP-1/GIP colocalization was rare. Our findings indicate that two L cell types exist, a proximal one secreting GLP-1 (and possibly CCK and neurotensin), and a distal one secreting GLP-1 and PYY. GIP seems to be secreted from cells that are not cosecreting other peptides.
BackgroundMice, rats, and pigs are the three most used animal models when studying gastrointestinal peptide hormones; however their distribution from the duodenum to the distal colon has not been characterized systematically across mice, rats and pigs. We therefore performed a comparative distribution analysis of the tissue content of the major appetite- and glucose regulatory peptides: glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), glucagon-like peptide-1 (GLP-2), oxyntomodulin/glicentin, neurotensin, and peptide YY (PYY) from the duodenum to distal colon in mice (n = 9), rats (n = 9) and pigs (n = 8), using validated radioimmunoassays.ResultsGLP-1, GLP-2 and oxyntomodulin/glicentin show similar patterns of distribution within the respective species, but for rats and pigs the highest levels were found in the distal small intestine, whereas for the mouse the highest level was found in the distal colon. In rats and pigs, neurotensin was predominantly detected in mid and lower part of the small intestine, while the mouse showed the highest levels in the distal small intestine. In contrast, the distribution of GIP was restricted to the proximal small intestine in all three species. Most surprisingly, in the pig PYY was found in large amounts in the proximal part of the small intestine whereas both rats and mice had undetectable levels until the distal small intestine.ConclusionsIn summary, the distribution patterns of extractable GIP, GLP-1, GLP-2, oxyntomodulin/glicentin, neurotensin are preserved across species whereas PYY distribution showed marked differences.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-016-1872-2) contains supplementary material, which is available to authorized users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.