Age-related increase in neuropeptide Y-like immunoreactivity in cerebrospinal fluid in women

In order to investigate the age-related changes in neuropeptide Y (NPY) in cerebrospinal fluid (CSF) of men and women, we examined the concentration of NPY-like immunoreactivity (NPY-LI) in CSF of a large population of Japanese men and women by specific radioimmunoassay (RIA). The dilution curve of CSF extract paralleled the standard curve of RIA for human NPY. Gel chromatographic studies revealed the presence of two peaks of NPY-LI, one emerging at the elution position of synthetic NPY and another emerging at a higher-molecular-weight position. NPY-LI in the CSF in 201 men (aged 17 to 69y) and 118 women (aged 17 to 69y) was 124 +/- 4 and 136 +/- 6 pg/ml (mean +/- SE), respectively. NPY-LI in the CSF of women, but not of men, increased significantly with aging. This finding suggests that the level of NPY with aging in the central nervous system (CNS) may be regulated somewhat differently in men and women.