INSULIN-LIKE GROWTH-FACTOR-I RECEPTORS IN HUMAN BRAIN AND PITUITARY-GLAND - AN AUTORADIOGRAPHIC STUDY

Insulin-like growth factor (IGF)-I receptors were studied in adult hum an postmortem brain and pituitary gland using quantitative autoradiogr aphy with human recombinant [I-125]IGF-I. The highest densities were f ound in the choroid plexus, pituitary gland-where IGF-I receptors were mainly concentrated in the anterior lobe, pineal gland, glomerular la yer of the olfactory bulb, and the molecular layer of the cerebellar c ortex. Moderate densities were present in cerebral cortex, caudate nuc leus, putamen, accumbens, the CA1, CA2, CA3 fields and dentate gyrus o f the hippocampus, the dendate nucleus of the cerebellum, amygdala, th alamus, pontine nuclei, and substantia nigra. All other brain areas, i ncluding white matter, contained low densities of IGF-I receptors. The finding that several well-defined brain structures are enriched with IGF-I receptors suggests a neurotrophic/survival or neuromodulatory ro le of insulin-like growth factors on specific neuronal systems. IGF-I receptors observed in the white matter may be associated with oligoden drocytes. (C) 1994 Wiley-Liss, Inc.