Mouse placental lactogen-I: RIA and gestational profile in maternal serum.
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.
Ogren
L
L
Department of Biology, University of California, Santa Cruz 95064.
Southard
J N
JN
Colosi
P
P
Linzer
D I
DI
Talamantes
F
F
D000818:Animals; D005260:Female; D008098:Litter Size; D051379:Mice; D010920:Placenta / Q000032:analysis; D010928:Placental Lactogen / Q000032:analysis / Q000097:blood*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood*; D011863:Radioimmunoassay / Q000379:methods; D011994:Recombinant Proteins / Q000032:analysis
D011994:Recombinant Proteins; D010928:Placental Lactogen