Involvement of autocrine mechanism of transforming growth factor-beta in the functional differentiation of pregnant mouse mammary gland.
We studied the presence and possible role of the autocrine mechanism of transforming growth factor-beta (TGF-beta) in pregnant mouse mammary gland. Northern blot analysis revealed the expression of the TGF-beta 1 gene transcript at 2.5 kb in mammary epithelial cells isolated from virgin and mid-pregnant mice. The TGF-beta activity was higher in the conditioned medium from mid-pregnant mouse mammary explants than that from virgin explants by a bioassay system using mink lung epithelial cells. A binding study using [125I]TGF-beta 1 as a ligand showed that pregnant mouse mammary epithelial cells possessed a single class of high-affinity TGF-beta 1 binding sites (Kd = 28.0 pmol/l, 1.2 x 10(4) sites per cell). These results suggested the presence of a TGF-beta autocrine mechanism in pregnant mouse mammary epithelial cells. Next, we examined the effect of TGF-beta 1 on the functional differentiation of pregnant mouse mammary gland. Transforming growth factor-beta 1 inhibited alpha-lactalbumin production in cultured mammary explants from mid-pregnant mice in a dose-dependent manner without inhibiting DNA synthesis. All these results suggest that TGF-beta may play a role in regulating the functional differentiation of mouse mammary glands during pregnancy.
Yamamoto
T
T
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Komura
H
H
Morishige
K
K
Tadokoro
C
C
Sakata
M
M
Kurachi
H
H
Miyake
A
A
D000818:Animals; D015152:Blotting, Northern; D002454:Cell Differentiation / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism / Q000502:physiology; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D007768:Lactalbumin / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000166:cytology* / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D007768:Lactalbumin