Oestrogen attenuates post-exercise myeloperoxidase activity in skeletal muscle of male rats

• Published in: Acta physiologica Scandinavica 1999-06, Vol.166 (2), p.85-90
• Main Authors: TIIDUS, P. M, BOMBARDIER, E
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Estradiol - analogs & derivatives; Estradiol - pharmacology; exercise; Female; Fundamental and applied biological sciences. Psychology; inflammation; Liver - drug effects; Liver - enzymology; Male; muscle damage; Muscle, Skeletal - drug effects; Muscle, Skeletal - enzymology; myeloperoxidase; neutrophils; Neutrophils - pathology; oestrogen; Peroxidase - metabolism; Physical Conditioning, Animal - physiology; Rats; Rats, Sprague-Dawley; Space life sciences; Striated muscle. Tendons; Vertebrates: osteoarticular system, musculoskeletal system
• ISSN: 0001-6772; 1365-201X
• DOI: 10.1046/j.1365-201x.1999.00550.x

The effects of 2 weeks of oestrogen (40 μg kg BW–1β‐estradiol 3‐benzoate) injection on 24 h post‐exercise myeloperoxidase (MPO) activities were determined in plantaris and soleus muscles and liver of sexually mature male and female rats. The treadmill running protocol (45–60 min, at 28 m min–1, 15% grade) induced significant elevations in muscle MPO activities 24 h post‐exercise in male rats, while prior oestrogen administration to male rats eliminated the post‐exercise elevations in muscle MPO activities. Female rats experienced no significant post‐exercise elevations in muscle MPO activities. Hence oestrogen administration to male rats attenuated post‐exercise muscle MPO activities to levels found in female animals. Liver MPO activities were not significantly affected by exercise, gender or oestrogen administration. Oestrogen may be a factor in diminishing 24 h post‐exercise skeletal muscle leukocyte infiltration and inflammatory response in both male and female muscle.