title: Specific receptors and growth effects of insulin and insulin-like growth factors in a human cell line derived from mixed mesodermal tumor of the uterus.
abstract: OBJECTIVE
  Mixed mesodermal tumors of the uterus are highly malignant. The purpose of our present study was to investigate possible roles of insulin and insulin-like growth factors I and II (IGF-I and IGF-II) in the growth and development of these tumors.
  
  
  METHODS
  Specific binding and growth effects of insulin, IGF-I, and IGF-II were studied in SK-UT-1 cells, derived from a human mixed mesodermal tumor of the uterus. The receptors were further characterized by competitive binding and chemical cross-linking studies.
  
  
  RESULTS
  Binding studies with 125I-insulin, 125I-IGF-I, and 125I-IGF-II revealed the presence of specific binding sites for these three growth factors. Specificity studies revealed that the binding sites for IGF-I and IGF-II are distinct. Binding of IGF-II was much higher than insulin and IGF-I binding. Scatchard analysis of the binding data revealed that the cell line has a higher number of IGF-II receptor (100,000 sites per cell) than insulin (1400 sites per cell) and IGF-1 (1200 sites per cell) receptors. The effect of these growth factors on cell growth was studied by monitoring the cell number and incorporation of [3H] thymidine into the DNA of the cells. Insulin-like growth factor-II was potent in stimulating the growth of these cells, but IGF-I did not have any effect. Insulin stimulated DNA synthesis only at pharmacologic concentrations.
  
  
  CONCLUSIONS
  These results indicate that IGF-II is mitogenic to mixed mesodermal tumors of the uterus. Insulin-like growth factor II may be involved in the growth regulation of mixed mesodermal tumors of the uterus.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston 77555-0587, USA.
authors.forename: M
authors.initials: M
authors.lastname: Nagamani
authors.forename: C A
authors.initials: CA
authors.lastname: Stuart
mesh_terms: D001667:Binding, Competitive; D002455:Cell Division / Q000187:drug effects; D003432:Cross-Linking Reagents; D004247:DNA / Q000096:biosynthesis; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000378:metabolism / Q000494:pharmacology; D018199:Mixed Tumor, Mesodermal / Q000378:metabolism*; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D017527:Receptor, IGF Type 2 / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism*; D017451:Receptors, Somatomedin / Q000378:metabolism*; D013002:Somatomedins / Q000378:metabolism / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014594:Uterine Neoplasms / Q000378:metabolism*
chemical_list: D003432:Cross-Linking Reagents; D007328:Insulin; D017527:Receptor, IGF Type 2; D017451:Receptors, Somatomedin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D004247:DNA; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin