Transforming growth factor activity in human colostrum.

Abstract

When human milk was examined for the presence of transforming growth factor (TGF) activity, high levels of the activity were found in milk collected in the early days after delivery. Fractionation of an acid-ethanol extract of colostrum by Bio-Gel P-60 column chromatography revealed that the activity was found in two molecular weight ranges; over 45,000 and from 10,000 to 20,000 daltons. The activity of the milk TGF did not compete with epidermal growth factor (EGF) for EGF receptor and was potentiated by the addition of EGF when assayed using normal rat kidney (NRK) cells.