Griffin, AE, Macdonald, R, Wagenmakers, AJM, Marshall, JM and Poucher, SM (2017) Development of microdialysis methodology for interstitial insulin measurement in rodents. Journal of Pharmacological Toxicology Methods, 86. pp. 67-75. ISSN 1056-8719

Preview

Text FinalAcceptedMSJPharmToxicolMethods2017.pdf - Accepted Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (780kB) | Preview

Abstract

INTRODUCTION: Accurate assessment of muscle insulin sensitivity requires measurement of insulin concentration in interstitial fluid (ISF), but has proved difficult. We aimed to optimise measurement of ISF insulin concentrations in rat muscles in vivo using microdialysis. METHODS: Factorial experimental design experiments were performed in vitro to determine optimal conditions for insulin recovery with microdialysis probes. These conditions were tested in vivo, adjusted appropriately and used in lean and obese Zucker rats to compare ISF insulin concentrations basally and during hyperinsulinaemic-euglycaemic (HE) clamp. RESULTS: Optimal conditions in vivo were: a 100kDa microdialysis probe inserted in muscle, perfused with 1% BSA, 1.5mM glucose in 0.9% sodium chloride at 1μl/min. Samples were collected into siliconised glass microvials. As a reference for insulin, we established a protocol of inulin infusion, beginning at -80min and reaching equilibrium within 60min. HE clamp, beginning at 0min, increased ISF insulin concentration from 122±56 basally to 429±180pmol/l (P<0.05) in lean rats and from 643±165 to 1087±243pmol/l (P=0.07) in obese rats; ISF insulin concentrations were significantly higher throughout in obese rats. The difference between ISF and plasma insulin concentration (ISF:plasma ratio) was substantially higher in obese rats, but fell to similar values in obese and lean rats during HE clamp. DISCUSSION: Optimising insulin recovery with microdialysis allowed accurate measurement of basal ISF insulin in muscle of lean and obese Zucker rats and indicates insulin transport across capillaries is impaired in obese rats, basally and during hyperinsulinaemia.

Item Type:	Article
Uncontrolled Keywords:	1115 Pharmacology And Pharmaceutical Sciences
Subjects:	R Medicine > R Medicine (General) R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions:	Sport & Exercise Sciences
Publisher:	Elsevier
Related URLs:	Author
Date Deposited:	04 May 2017 10:57
Last Modified:	21 Mar 2022 12:54
DOI or ID number:	10.1016/j.vascn.2017.04.001
URI:	https://researchonline.ljmu.ac.uk/id/eprint/6352

View Item