Mouse placental lactogen-I: RIA and gestational profile in maternal serum

Endocrinology. 1989 Nov;125(5):2253-7. doi: 10.1210/endo-125-5-2253.


A RIA for mouse placental lactogen-I (mPL-I) was developed using recombinant mPL-I as the standard, radioligand, and antigen for antiserum production. Displacement curves for dilutions of serum and placental extracts from pregnant mice were parallel to the recombinant mPL-I standard curve. Serum from male and nonpregnant female mice and high concentrations of mouse PRL, GH, PL-II, proliferin, and proliferin-related protein did not cross-react in the assay. mPL-I appeared in maternal serum on day 6 of pregnancy. Its concentration remained low until day 8 and them increased to a very large peak on days 9-11 (maximum concentration, approximately 8 micrograms/ml). The mPL-I concentration declined after day 11, but the hormone could be detected at low concentration in maternal serum until the end of pregnancy. On day 10 of pregnancy, the mPL-I concentration of maternal serum was correlated with litter size. Fractionation of serum from 10-day pregnant mice by size exclusion chromatography indicated the absence of high mol wt forms of mPL-I in the circulation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Female
  • Litter Size
  • Mice
  • Placenta / analysis
  • Placental Lactogen / analysis
  • Placental Lactogen / blood*
  • Pregnancy
  • Pregnancy, Animal / blood*
  • Radioimmunoassay / methods
  • Recombinant Proteins / analysis


  • Recombinant Proteins
  • Placental Lactogen