title: Amniotic fluid and plasma concentrations of pregnancy-associated plasma protein-A (PAPP-A) throughout pregnancy: comparison with other fetoplacental products.
abstract: The development of a sensitive radioimmunoassay has enabled measurements of pregnancy-associated plasma protein-A (PAPP-A) to be performed from early pregnancy. The present paper compares the plasma concentrations of PAPP-A with the levels of two trophoblastic proteins, human placental lactogen (hPL) and the beta-subunit of human chorionic gonadotrophin (beta-hCG), with a steroid of fetoplacental origin, total oestriol (total E3), and with a fetal protein, alpha-fetoprotein (AFP). PAPP-A was also measured in amniotic fluid and in maternal urine. In contrast with the secretion of the other substances studied, which either reach a plateau or even decrease during the last 4 weeks of pregnancy, PAPP-A steadily increased in the maternal circulation from 7 to 40 weeks gestation. It is proposed that PAPP-A production is either not related to placental mass or that PAPP-A is not of trophoblastic origin. The increase of PAPP-A in amniotic fluids parallels the increase in maternal blood; virtually no PAPP-A is excreted in urine.
mesh_terms: D000653:Amniotic Fluid / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000378:metabolism; D018997:Chorionic Gonadotropin, beta Subunit, Human; D005260:Female; D006801:Humans; D010446:Peptide Fragments / Q000378:metabolism; D010928:Placental Lactogen / Q000378:metabolism; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000378:metabolism*; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*; D011863:Radioimmunoassay; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments; D011257:Pregnancy Proteins; D000509:alpha-Fetoproteins; D010928:Placental Lactogen; D011266:Pregnancy-Associated Plasma Protein-A