Background Tendon ruptures have been linked to anabolic steroid usage, suggesting pathological changes in tendon structure due to steroid intake. Anecdotal reports from athletes suggest a protective effect of GH on tendon, especially in those who use anabolic steroids.

Aim To investigate how administration of insulin-like growth factor 1 (IGF-1), anabolic steroid and combination of the two affect the expression of genes involved in collagen metabolism.

Methods Fascicles were harvested from bovine extensor tendons: n=4 to calculate optimal loading and n=8 to assess hormone plus optimal loading effect on eight genes involved in collagen metabolism. Total RNA was extracted and mRNA expression analysed by quantitative real-time reverse transcription-PCR, normalised to GAPDH and 18S ribosomal RNA±control (Con).

Results Maximal collagen expression occurred at 6 h of light exercise, following 1 h of heavy loading. One tendon failed to have RNA extracted and was therefore removed from the study (n=7). IL-6 expression was significantly higher than control when exercised fascicles were exposed to: (1) anabolic steroid (normalised to: 18S; GAPDH; 18S & Con and GAPDH & Con); (2) IGF-1 (normalised to: GAPDH; 18S & Con and GAPDH & Con); (3) Dulbecco’s modified Eagle’s medium & PenStrep (normalised to: 18S & Con and GAPDH & Con) and (4) anabolic steroid & IGF-1 (normalised to: 18S & Con and GAPDH & Con).

Conclusion The results of this study suggest that tendon is an IL-6 producing region during exercise which may also contribute to IL-6 increases in plasma during exercise.