The effect of epidermal growth factor, transforming growth factor and breast tumour homogenates on the activity of oestradiol 17 beta hydroxysteroid dehydrogenase in cultured adipose tissue.

The effect of epidermal growth factor (EGF), transforming growth factor (TGF alpha) and breast tumour homogenates on oestradiol 17 beta hydroxysteroid dehydrogenase (E2DH) activity has been examined using cultured human breast adipose tissue. EGF (100-1000 ng/ml) inhibited E2DH activity (E1----E2) in a dose dependent manner. TGF alpha (250 and 500 ng/ml) stimulated E2DH activity, with conversion of E1----E2 increasing to a greater degree than E2----E1 activity. Breast tumour homogenates (2-10% w/v) also influenced E2DH activity. It is concluded that growth factors, produced by breast tumours, may modulate E2DH activity in tissues surrounding the tumour and thereby influence tumour growth.