MMP9 and Duchenne muscular dystrophy: In particular, we hypothesized that ADAMTS-5 and MMP-9, two metalloproteinases, overexpressed in DMD patients and in mdx mice (56, 57), might be potential novel targets of GHSs in skeletal muscle, based on the observation that both compounds may indeed act as inhibitors of other metalloproteinases, such ACE.