Aw. Sudlow et al., TRANSFORMING GROWTH-FACTOR-BETA-1 INHIBITS CASEIN SECRETION FROM DIFFERENTIATING MAMMARY-GLAND EXPLANTS BUT NOT FROM LACTATING MAMMARY CELLS, Biochemical journal, 304, 1994, pp. 333-336
Transforming growth factor-beta (TGF beta) is important in the maturat
ion and function of the mammary gland and is present in milk. We have
examined whether, in addition to inhibiting lactogenesis, TGF beta exe
rts acute regulatory effects on lactating mammary cells. The isoform T
GF beta 1 at 5 and 50 ng/ml suppressed the onset of lactation and the
subsequent production of beta-casein by differentiating mouse mammary
explants from pregnant mice. By contrast, it did not inhibit protein s
ynthesis or secretion from acini isolated from lactating-mouse mammary
gland or protein secretion from explants from lactating mice. These d
ata indicate that TGF beta inhibits the onset of casein secretion, but
is not an acute regulator of casein synthesis or secretion from diffe
rentiated lactating mammary cells.