Transforming growth factor (TGF)-alpha in human milk.
Transforming growth factor (TGF)-alpha and epidermal growth factor (EGF) were measured in human milk by means of homologous radioimmunoassay. As previously reported, EGF concentration in the colostrum was approximately 200 ng/ml and decreased to 50 ng/ml by day 7 postpartum. The value of immunoreactive (IR)-TGF-alpha was 2.2-7.2 ng/ml, much lower than that of EGF. In contrast to EGF, the concentration of IR-TGF-alpha was fairly stable during the 7 postpartum days. There was no relationship between the concentrations of IR-TGF-alpha and IR-EGF, suggesting that the regulatory mechanism in the release of the two growth factors is different. On gel-chromatography using a Sephadex G-50 column, IR-EGF appeared in the fraction corresponding to that of authentic human EGF, while 70%-80% of the IR-TGF-alpha was eluted as a species with a molecular weight greater than that of authentic human TGF-alpha. Although the physiological role of TGF-alpha in milk is not known, it is possible that it is involved in the development of the mammary gland and/or the growth of newborn infants.
Okada
M
M
Research Institute for Growth Sciences, Tokyo, Japan.
Ohmura
E
E
Kamiya
Y
Y
Murakami
H
H
Onoda
N
N
Iwashita
M
M
Wakai
K
K
Tsushima
T
T
Shizume
K
K
D004815:Epidermal Growth Factor / Q000032:analysis; D005260:Female; D006801:Humans; D008895:Milk, Human / Q000737:chemistry*; D011863:Radioimmunoassay / Q000379:methods; D016211:Transforming Growth Factor alpha / Q000032:analysis*
D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor