Mitogenic activity and epidermal growth factor content in human milk.

The concentration of epidermal growth factor (EGF) was determined by radioimmunoassay in colostral and mature human milk. The content of EGF in colostral milk was 25-38 ng/ml compared to 5.2-11.5 ng/ml in samples of mature milk. The radioimmunoassayable EGF content in mature milk was not influenced by pasteurization and EGF was detected in a preparation of human milk protein at a concentration similar to that found in mature milk. The growth promoting activity in human milk measured by 3H-thymidine incorporation in human fibroblasts was higher in colostral milk (stimulated incorporation 8.7 fold) than in mature milk (stimulated incorporation about 7-fold).