Insulin-like growth factor binding proteins in cerebrospinal fluid during human development and aging

We analyzed samples of insulin-like growth factor binding proteins (IGFBPs) in human cerebrospinal fluid (CSF) in neurologically normal patients from one day after birth to age 76 years. CSF samples were separated on SDS-PAGE and then transferred to nitrocellulose membranes where IGFBPs were detecte d by Western ligand blot using [I-125]-IGF-II, confirming other reports whe re we found the presence of IGFBP-2, 3, 4, 5. The 34 kDa IGFBP-2 was presen t in all samples, and progressively decreased with age. A broad 28- to 30-k Da IGFBP band, having the appearance of IGFBP-5, was triphasic: faint durin g infancy, barely detectable at 6 months, but intense in adult and aged ind ividuals. The 24-kDa IGFBP-4 band was only seen in neonatal CSF samples, wh ile the IGFBP-3 doublet gradually increased during aging. Thus, these prese nt results show that IGFBP-2, 3, 4 and 5 in CSF are developmentally regulat ed, suggesting roles for these molecules in the development of the nervous system, (C) 1999 Academic Press.