Steen Bønløkke Pedersen

GH signaling in skeletal muscle and adipose tissue in healthy human subjects: Impact of gender and age

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

Objective: The mechanisms underlying the impact of age and gender on the GH.IGF1 axis remain unclear. We tested the hypothesis that age and gender impacts on GH signaling in human subjects in vivo.. Design: 20 healthy non-obese adults ['young group' < 30 yrs (5F/5M) and 'old' group' > 60 yrs (5F/5M)] were studied after 1) an iv. GH bolus (0.5 mg), and 2) saline. Methods: Muscle and fat biopsies were obtained after 30 and 120 min. Total and phosphorylated STAT5b proteins, gene expression of IGF1, SOCS 1-3 and CISH, body composition, VO2-max and muscle strength were measured. Results: In the GH-unstimulated state women displayed significantly elevated levels of CISH mRNA in muscle (p=0.002) and fat (p=0.05) and reduced levels of IGF1 mRNA in fat. Phosphorylated STAT5b (pSTAT5b) was maximally increased in all subjects 30 min after GH exposure, and more pronounced in women as compared to men (P = 0.01). IGF1, SOCS 1-3 and CISH mRNA expression increased significantly in muscle after 120 min. in all subjects with no impact of age and gender. GH-induced pSTAT5b correlated inversely with LBM (r=-0.56, P=0.01) and positively with the CISH mRNA response (r = 0.533, P = 0.05). Conclusion: 1) GH signaling in muscle and fat after a single GH bolus in healthy human subjects is age-independent 2) we hypothesize that constitutive overexpression of CISH may contribute to the relative GH resistance in women, 3) experimental studies of the impact of sex steroid administration and physical training on GH signaling in human subjects in vivo are needed.

OriginalsprogEngelsk
TidsskriftEuropean journal of endocrinology / European Federation of Endocrine Societies
Vol/bind171
Nummer5
Sider (fra-til)623-631
Antal sider9
ISSN0804-4643
DOI
StatusUdgivet - 27 aug. 2014

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