Increased met-enkephalin plasma levels in hemodialysis patients with or without pruritus

Met-enkephalin plasma levels were measured in 21 hemodialysis patients with or without pruritus. The mean value was significantly increased in the total of the patients compared with that in ten healthy subjects. There was, however no correlation between met-enkephalin levels and the degree of pruritus. The findings suggest that the opioid system may be activated in this condition, although the relevance of this endogenous opioid peptide to pruritus remains to be determined.