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Non‐invasive sampling of interstitial fluid for the purpose of measuring IGF‐I during exercise training
Author(s) -
Nindl Bradley Charles,
Tuckow A. P.,
Harman E. A.,
Rarick K. R.,
Alemany J. A.,
Staab J. S.,
Faupel M. L.,
Khosravi M.J.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a834-c
Subject(s) - venipuncture , interstitial fluid , medicine , blood sampling , analysis of variance , chemistry , endocrinology , urology , surgery
IGF‐I has conventionally been measured in serum, however, interstitial fluid (ISF) remains as an unexplored biocompartment that IGF‐I also resides in and may be more biologically relevant due to its proximity to cells. This study compared IGF‐I in serum vs. IGF‐I in ISF before and after 8 weeks of exercise training. 29 men (28±5 yrs, 176±8 cm, 83±11 kg) had ISF obtained by a non‐invasive method that included the application of continuous vacuum pressure on forearm skin perforated with tiny micropores created by a focused laser beam had blood obtained by venipuncture. An ELISA measured total IGF‐I. A repeated measures ANOVA and Pearson Product Moment Correlation coefficients (p ≤ 0.05) were used for statistical analyses. Data are presented as mean±SE. Total ISF IGF‐I was significantly lower than serum IGF‐I both before (ISF: 91±6 ng/mL; serum: 375±17 ng/mL) and after (ISF: 83±5 ng/mL; serum: 363±19 ng/mL) training. Serum and ISF IGF‐I were not significantly different pre‐ to post‐training. Serum and ISF IGF‐I were significantly correlated pre (r = .41), but not post (r = .34) training. The percent change between serum and ISF was also significantly correlated (r = .58). Total IGF‐I can be measured in interstitial fluid via a non‐invasive manner and is appreciably (~76%) less than total IGF‐I measured in serum. IGF‐I measurements between serum and ISF were only moderately correlated possibly indicating an uncoupled, rather than a linked regulation of IGF‐I among the body's biocompartments.