Pituitary-placental interaction: hypophysectomy modulates the secretion of mouse placental lactogen-I.
To determine whether the pituitary gland influences the concentration of mouse placental lactogen-I (mPL-I) in maternal serum, pregnant Swiss Webster mice were hypophysectomized or sham-operated on day 9 of gestation. Blood was collected on days 10-13 and 18, and the mPL-I concentration of the serum was measured by RIA. The serum mPL-I concentration of hypophysectomized mice was significantly higher than that of sham-operated and intact mice on days 10-13. There was no difference in mPL-I concentration on day 18 of pregnancy among the groups. Similar elevations in serum mPL-I concentration were observed when hypophysectomy was performed on day 10 of pregnancy. Steady state levels of placental mPL-I messenger RNA (mRNA) were analyzed by Northern hybridization. No differences were observed in the amount of mPL-I mRNA among hypophysectomized, sham-operated, and intact mice. These results demonstrate that the pituitary gland exerts inhibitory control over the maternal serum mPL-I concentration. This control does not appear to be affected at the level of steady state amounts of mPL-I mRNA.
Department of Biology, Sinsheimer Laboratories, University of California, Santa Cruz 95064.
M F
MF
Lopez
F A
FA
Carrion
F
F
Talamantes
D000818:Animals; D005260:Female; D007016:Hypophysectomy; D051379:Mice; D009994:Osmolar Concentration; D010902:Pituitary Gland / Q000502:physiology*; D010920:Placenta / Q000378:metabolism / Q000502:physiology*; D010928:Placental Lactogen / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism
D012333:RNA, Messenger; D010928:Placental Lactogen