Abstract
A highly sensitive double-site enzyme immunoassay for epidermal growth factor (EGF) was used to quantify EGF concentrations in brain and cerebrospinal fluid of early postnatal and adult mice and rats. EGF was not detectable under any condition at sensitivity levels of 0.06 ng/g wet wt. These observations support the notion that EGF receptors on astrocytes are triggered by other growth factors than EGF.