title: Placental lactogen and growth hormone receptors in human fetal tissues: relationship to fetal plasma human placental lactogen concentrations and fetal growth.
abstract: The specific binding of human placental lactogen (hPL) and human GH (hGH) to particulate cell membranes from human fetal liver and skeletal muscle at 12-19 weeks gestation was examined. Fetal liver and muscle specifically bound [125I]hPL. This binding was inhibited by increasing concentrations of unlabeled hPL (half-maximal concentrations, 2.2 and 3.4 nmol/L, respectively). Scatchard analysis of the hepatic membrane binding revealed curvilinear plots with higher (Kd, 2.2 nmol/L) and lower (Kd, 24 nmol/L) affinity sites, while binding to muscle involved a single receptor class of Kd 5.6 nmol/L. The binding capacities for the two hepatic sites correlated positively with fetal body weight. [125I]hGH specifically bound to liver, but not muscle, with higher (Kd, 1.6 nmol/L) and lower (Kd, 8.6 nmol/L) affinity sites. [125I]PRL bound to hepatic membranes, but was preferentially displaced by hPL or hGH. Between 4 and 500 micrograms/L (mean, 82 micrograms/L, 3.8 nmol/L) hPL were present in fetal plasma. The findings identify distinct hPL receptors in human fetal liver and skeletal muscle and a hepatic hGH receptor in midgestation.
authors: Department of Paediatrics, University of Sheffield, Northern General Hospital, United Kingdom.
authors: D J
authors: DJ
authors: Hill
authors: M
authors: M
authors: Freemark
authors: A J
authors: AJ
authors: Strain
authors: S
authors: S
authors: Handwerger
authors: R D
authors: RD
authors: Milner
mesh_terms: D005314:Embryonic and Fetal Development; D005312:Fetal Blood; D005333:Fetus / Q000378:metabolism*; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D008566:Membranes / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D009994:Osmolar Concentration; D010928:Placental Lactogen / Q000097:blood* / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism; D018000:Receptors, Peptide; D011981:Receptors, Prolactin / Q000378:metabolism*; D011986:Receptors, Somatotropin / Q000378:metabolism*
chemical_list: D018000:Receptors, Peptide; D011981:Receptors, Prolactin; D011986:Receptors, Somatotropin; C028202:placental lactogen receptor; D011388:Prolactin; D013006:Growth Hormone; D010928:Placental Lactogen