Recombinant human nerve growth factor is biologically active and labels novel high-affinity binding sites in rat brain

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.88.1.281· OSTI ID:6250119

Altar, C A; Burton, L E; Bennett, G L; Dugich-Djordjevic, M ^[1]

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1. Genentech, Inc., South San Francisco, CA (USA)

Iodinated recombinant human nerve growth factor (125I-rhNGF) stimulated neurite formation in PC12 cell cultures with a half-maximal potency of 35-49 pg/ml, compared with 39-52 pg/ml for rhNGF. In quantitative ligand autoradiography, the in vitro equilibrium binding of 125I-rhNGF to brain sections showed a 10-fold regional variation in density and was saturable, reversible, and specifically displaced by up to 74% with rhNGF or murine NGF (muNGF). At equilibrium, 125I-rhNGF bound to these sites with high affinity and low capacity (Bmax less than or equal to 13.2 fmol/mg of protein). Calculation of 125I-rhNGF binding affinity by kinetic methods gave average Kd values of 24 and 31 pM. Computer-generated maps revealed binding in brain regions not identified previously with 125I-muNGF, including hippocampus; dentate gyrus; amygdala; paraventricular thalamus; frontal, parietal, occipital, and cingulate cortices; nucleus accumbens; olfactory tubercle; subiculum; pineal gland; and medial geniculate nucleus. NGF binding sites were distributed in a 2-fold increasing medial-lateral gradient in the caudate-putamen and a 2-fold lateral-medial gradient in the nucleus accumbens. 125I-rhNGF binding sites were also found in most areas labeled by 125I-muNGF, including the interpedunucular nucleus, cerebellum, forebrain cholinergic nuclei, caudoventral caudate-putamen, and trigeminal nerve nucleus. 125I-rhNGF binding sites were absent from areas replete with low-affinity NGF binding sites, including circumventricular organs, myelinated fiber bundles, and choroid plexus. The present analysis provides an anatomical differentiation of high-affinity 125I-rhNGF binding sites and greatly expands the number of brain structures that may respond to endogenous NGF or exogenously administered rhNGF.

• OSTI ID: 6250119
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 88:1; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GROWTH FACTORS
BIOCHEMICAL REACTION KINETICS
AFFINITY
AUTORADIOGRAPHY
BRAIN
IODINE 125
LIGANDS
MAN
NERVES
RATS
RECEPTORS
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MITOGENS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques