Corticosterone is required for the prolactin receptor gene expression in the late pregnant mouse mammary gland.
In order to clarify the prolactin receptor (PRL-R) gene expression at lactogenesis, the levels of the long and short forms of PRL-R mRNA were determined by the competitive RT-PCR in the pregnant, lactating and ovariectomized midpregnant mouse mammary gland. Plasma concentrations of corticosterone and progesterone were determined by RIA. The long form of PRL-R mRNA level was low until 10:00 on day 18, increased 3.3-fold at 22:00 on day 18 of pregnancy and further increased to 4.6-fold at 10:00 on day 0 of lactation. The short form of PRL-R mRNA level remained unchanged during this time period. The corticosterone:progesterone ratio increased 15.5-fold during the last 1.5 days of pregnancy. Corticosterone increased the long form of PRL-R mRNA level when the tissues on day 17 were cultured. On day 12 of pregnancy and following ovariectomy, corticosterone was exceedingly high from 2 h to 8 h and the corticosterone:progesterone ratio changed prior to the increase in the long form of PRL-R mRNA level. We conclude that corticosterone increases the PRL-R gene expression in the mammary gland before the onset of parturition.
Mizoguchi
Y
Y
Department of Animal Breeding, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Japan.
Yamaguchi
H
H
Aoki
F
F
Enami
J
J
Sakai
S
S
D000818:Animals; D003345:Corticosterone / Q000235:genetics* / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008321:Mammary Glands, Animal / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D010052:Ovariectomy; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000235:genetics* / Q000378:metabolism; D011981:Receptors, Prolactin / Q000096:biosynthesis / Q000235:genetics*
D011981:Receptors, Prolactin; D003345:Corticosterone