Nerve growth factor (NGF) is present in human placenta and semen, but undetectable in normal and Paget's disease blood: measurements with an anti-mouse-NGF enzyme immunoassay using a recombinant human NGF reference.

An enzyme immunoassay (EIA) originally developed for mouse beta-nerve growth factor (NGF) and commercially available was validated for human NGF. Cell culture medium containing bioactive recombinant human NGF was used as a reference, and mouse 2.5S beta-NGF as a standard. One of three human placentas contained measurable NGF (70 pg/g of tissue of mouse beta-NGF equivalents), a second detectable, and a third undetectable NGF. In three human semen samples NGF content ranged from 0.13 - 1.4 ng/ml. NGF could not be detected in normal human serum and in plasma from patients with Paget's disease, although mouse 2.5S beta-NGF added to human blood could be completely recovered from the serum.