A novel, noninvasive transdermal fluid sampling methodology: IGF-I measurement following exercise

作者:Scofield D E; McClung H L; McClung J P; Kraemer W J; Rarick K R; Pierce J R; Cloutier G J; Fielding R A; Matheny R W Jr; Young A J; Nindl B C*
来源:American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, 2011, 300(6): R1326-R1332.
DOI:10.1152/ajpregu.00313.2010

摘要

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% (V) over dotO(2peak)) 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.

  • 出版日期2011-6