Epidermal growth factor in cow's milk and milk formulas.

Epidermal growth factor (EGF) in human milk, cow's milk and 10 different milk formulas was measured by radioreceptor assay (RRA) using human placental membrane as an EGF receptor. The raw and pasteurized cow's milk contained 324.2 ng/ml and 155.0 ng/ml of RRA-EGF, respectively. These values were almost the same as that found in human milk, when the concentration was expressed as the proportion of protein contents in the samples. On the other hand, no trace of RRA-EGF was detected in 9 different milk formulas, and only one contained a very small amount of it.