University of Surrey

Test tubes in the lab Research in the ATI Dance Research

Serum Levels of Retinol Binding Protein 4 (RBP4) and Adipose Tissue Expression Levels of Protein Tyrosine Phosphatase 1B (PTP1B) are Increased in Obese Men Resident in North East of Scotland Without Any Changes in Endoplasmic Reticulum (ER) Stress Response Marker Genes

Hoggard, N, Agouni, A, Mody, N and Delibegovic, M (2012) Serum Levels of Retinol Binding Protein 4 (RBP4) and Adipose Tissue Expression Levels of Protein Tyrosine Phosphatase 1B (PTP1B) are Increased in Obese Men Resident in North East of Scotland Without Any Changes in Endoplasmic Reticulum (ER) Stress Response Marker Genes International Journal of General Medicine, 2012 (5). 403 - 411. ISSN 1178-7074

[img] Microsoft Word
Final_Paper_text_vs_16_3_2012 (2).doc
Restricted to Repository staff only

Download (125kB)
[img]
Preview
PDF
Figure1.pdf

Download (60kB)
[img]
Preview
PDF
Figure 2.pdf

Download (57kB)
[img]
Preview
PDF
Figure 3.pdf

Download (30kB)
[img]
Preview
PDF
AGOUNI_Serum_levels.pdf

Download (110kB)

Abstract

Background: Retinol-binding protein 4 (RBP4) is an adipokine identified as a marker of insulin resistance in mice and humans. Protein tyrosine phosphatase 1B (PTP1B) expression levels, as well as other genes involved in the endoplasmic-reticulum (ER) stress response, are increased in adipose tissue of obese, high-fat diet fed mice. In this study, we investigated if serum- and/or adipose-tissue RBP4 protein levels, and expression levels of PTP1B and other ER stress-response genes, are altered in obese and obese/diabetic men resident in North East of Scotland. Methods: We studied three groups of male volunteers: 1) normal/overweight (body mass index (BMI) <30), 2) obese (BMI>30) and 3) obese/diabetic group (BMI>30) controlling their diabetes either by diet or anti-diabetic drug, metformin. We analysed their serum- and adipose-tissue RBP4 protein levels, as well as adipose tissue mRNA expression of PTP1B, BIP (binding immunoglobulinprotein), ATF4 (activated transcription factor 4) and GRP94 (glucose-regulated protein 94), alongside other markers of adiposity (% body fat, leptin, cholesterol, triglycerides) and insulin resistance (oral glucose tolerance tests (OGTT), insulin, HOMA-IR, C-reactive protein (CRP), adiponectin). Results: We found that obese Scottish subjects had significantly higher serum-RBP4 protein levels in comparison to the normal/overweight subjects (p<0.01). Serum-RBP4 levels were normalized in obese/diabetic subjects treated with diet or metformin (p<0.05). Adipose-tissue RBP4 protein levels were comparable between all three groups of subjects and so were serum- and adipose-transthyretin (TTR) levels. Adipose-tissue PTP1B mRNA levels were increased in obese subjects in comparison to normal/overweight subjects (p<0.05), however diet and/or metformin treatment did not reverse this effect. Adipose-tissue BIP, ATF4 and GRP94 expression levels were unchanged in obese and obese/diabetic subjects. Conclusions: Human obesity results in an increase in serum, but not adipose-tissue, RBP4 protein levels and these are normalized in obese/diabetic subjects, which exhibit improvements in insulin sensitivity through diet or metformin treatment. However, whilst adipose-tissue PTP1B mRNA levels do increase in obese Scottish subjects, these remain high in obese/diabetics on diet or metformin treatment.

Item Type: Article
Additional Information: This is an author's version of an article originally published in International Journal of General Medicine,Dove Press, 2012. DOI: 10.2147/IJGM.S25879
Divisions: Faculty of Health and Medical Sciences > Biochemistry and Physiology
Depositing User: Symplectic Elements
Date Deposited: 04 May 2012 11:07
Last Modified: 23 Sep 2013 19:21
URI: http://epubs.surrey.ac.uk/id/eprint/401277

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year


Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800