Interleukin 6 inhibits mouse placental lactogen II but not mouse placental lactogen I secretion in vitro.
The mouse placenta produces several polypeptides belonging to the prolactin-growth hormone gene family, including mouse placental lactogen (mPL) I and mPL-II. The present study was undertaken to determine whether the secretion of mPL-I and mPL-II is regulated by interleukin 6 (IL-6), which is present in the placenta and has previously been reported to stimulate the secretion of pituitary members of this gene family. Effects of human and mouse IL-6 on mPL-I and mPL-II secretion were examined in primary cultures of placental cells from days 7, 9, and 12 of pregnancy. IL-6 caused a dose-dependent reduction in the mPL-II concentration in the medium of cells from days 9 and 12 of pregnancy but did not affect the mPL-II concentration in the medium of cells from day 7 of pregnancy or the mPL-I concentration in the medium of cells from days 7 or 9 of pregnancy. The lowest concentration of human IL-6 that significantly inhibited mPL-II secretion was 250 pM. The effect of IL-6 on the mPL-II concentration in the medium was due primarily to inhibition of mPL-II synthesis, which resulted at least partly from a decrease in the steady-state level of mPL-II mRNA. These data raise the possibility that IL-6 may regulate mPL-II production after midpregnancy in vivo.
Yamaguchi
M
M
Department of Biology, University of California, Santa Cruz 95064.
Ogren
L
L
Southard
J N
JN
Kurachi
H
H
Miyake
A
A
Talamantes
F
F
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D015342:DNA Probes; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D010920:Placenta / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D010928:Placental Lactogen / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology
D015342:DNA Probes; D015850:Interleukin-6; D012333:RNA, Messenger; D011994:Recombinant Proteins; C062303:placental lactogen II; D010928:Placental Lactogen