Prevention of exercise-induced muscle membrane damage by oestradiol.

Exercise can damage the muscle membrane, followed by leakage of certain muscle proteins into the bloodstream. This postexercise response differs for males and females; as an explanation for this difference it has been suggested that oestrogens have a protective effect on the female muscle membrane. We recently developed an animal exercise model in which postexercise damage can be studied in laboratory animals in vivo. A postexercise dimorphism, similar to that in humans, exists in rats and indirect evidence for the involvement of oestradiol (E2) was found. We report here 1) that ovariectomized females show postexercise damage like males, 2) that this response can be prevented by E2-replacement before exercise, and 3) that males, after E2-treatment, no longer show postexercise muscle damage. We therefore conclude that oestradiol indeed plays an important role in protecting skeletal muscle, both in females and in males.