Age-related changes of methionine-enkephalin and beta-endorphin/beta-lipotropin immunoreactivity in human CSF

Methionine-enkephalin (ME-IR) and beta-endorphin (BE-IR) immunoreactive material CSF concentrations have been measured in subjects of different ages affected by lumbar or cervical disk hernia. The two peptides exhibited different age-related trends. ME-IR levels rose significantly with age while no changes were observed in the case of BE-IR.