Faculty Collaboration Database

A novel, noninvasive transdermal fluid sampling methodology: IGF-I measurement following exercise. Am J Physiol Regul Integr Comp Physiol 2011 Jun;300(6):R1326-32

Date

03/11/2011

Pubmed ID

21389329

DOI

10.1152/ajpregu.00313.2010

Scopus ID

2-s2.0-79958808926 (requires institutional sign-in at Scopus site)   8 Citations

Abstract

This study tested the hypothesis that transdermal fluid (TDF) provides a more sensitive and accurate measure of exercise-induced increases in insulin-like growth factor-I (IGF-I) than serum, and that these increases are detectable proximal, but not distal, to the exercising muscle. A novel, noninvasive methodology was used to collect TDF, followed by sampling of total IGF-I (tIGF-I) and free IGF-I (fIGF-I) in TDF and serum following an acute bout of exercise. Experiment 1: eight men (23 ± 3 yrs, 79 ± 7 kg) underwent two conditions (resting and 60 min of cycling exercise at 60% Vo(2)(peak)) in which serum and forearm TDF were collected for comparison. There were no significant changes in tIGF-I or fIGF-I in TDF obtained from the forearm or from serum following exercise (P > 0.05); however, the proportion of fIGF-I to tIGF-I in TDF was approximately fourfold greater than that of serum (P ≤ 0.05). These data suggest that changes in TDF IGF-I are not evident when TDF is sampled distal from the working tissue. To determine whether exercise-induced increases in local IGF-I could be detected when TDF was sampled directly over the active muscle group, we performed a second experiment. Experiment 2: fourteen subjects (22 ± 4 yr, 68 ± 11 kg) underwent an acute plyometric exercise condition consisting of 10 sets of 10 plyometric jumps with 2-min rest between sets. We observed a significant increase in TDF tIGF-I following exercise (P ≤ 0.05) but no change in serum tIGF-I (P > 0.05). Overall, these data suggest that TDF may provide a noninvasive means of monitoring acute exercise-induced changes in local IGF-I when sampled in proximity to exercising muscles. Moreover, our finding that the proportion of free to tIGF-I was greater in TDF than in serum suggests that changes in local IGF-I may be captured more readily using this system.

Author List

Scofield DE, McClung HL, McClung JP, Kraemer WJ, Rarick KR, Pierce JR, Cloutier GJ, Fielding RA, Matheny RW Jr, Young AJ, Nindl BC

Author

Kevin Richard Rarick PhD Assistant Professor in the Pediatrics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adolescent
Adult
Bicycling
Exercise
Female
Forearm
Humans
Insulin-Like Growth Factor I
Lasers
Male
Rest
Skin
Specimen Handling
Vacuum Curettage
Young Adult