Production and action of insulin-like growth factor I/somatomedin C in primary cultures of fetal lung fibroblasts.
Production of insulin-like growth factor I/somatomedin C (IGF-I) by 19-day-gestation fetal rat lung fibroblasts was studied, and a paracrine (local production and action) mitogenic activity of this growth factor was explored. Specific IGF-I mRNAs were demonstrated in these cells, consistent with production of IGF-I. Using an IGF-I monoclonal antibody, IGF-I-like material was isolated from fetal lung fibroblast conditioned medium (FCM) and separated by molecular weight. Several molecular weight species were identified, including an 8,000 to 10,000 molecular weight species, a weight similar to purified IGF-I. IGF-I binding proteins elaborated by these cells were also demonstrated. The possibility of a paracrine mitogenic activity of the fetal lung fibroblast-produced IGF-I in cultures was suggested by demonstrating a reduction in DNA synthesis in cultures incubated with either the IGF-I monoclonal antibody or an IGF-I receptor antibody. These findings indicate that 19-day-gestation fetal rat lung fibroblasts produce IGF-I that acts in a paracrine fashion and suggest that this growth factor is biologically active during fetal lung development.
Stiles
A D
AD
Department of Pediatrics, University of North Carolina, Chapel Hill 27599.
Moats-Staats
B M
BM
D000818:Animals; D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D004261:DNA Replication; D005260:Female; D005333:Fetus; D005347:Fibroblasts / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D008168:Lung / Q000502:physiology*; D008970:Molecular Weight; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D011247:Pregnancy; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000502:physiology; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000235:genetics*
D000911:Antibodies, Monoclonal; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D013002:Somatomedins; D011061:Poly A; D012313:RNA; D007334:Insulin-Like Growth Factor I