Fibroblast growth factor enhances human chorionic gonadotropin synthesis independent of mitogenic stimulation in Jar choriocarcinoma cells.
The Jar choriocarcinoma cell line was used as an in vitro placental cell model to determine the effects of polypeptide growth factors on hCG beta secretion. Epidermal and fibroblast growth factor (FGF) treatment of serum-free cultures stimulated hCG beta secretion 2.5- and 4.0-fold over basal serum-free control levels within a 15-h incubation period. Insulin-like growth factor I, nerve growth factor, and transforming growth factor-beta had no significant effect on hCG beta secretion. FGF at concentrations as low as 0.125 ng/ml significantly elevated medium hCG beta levels without increasing cell number or total cellular protein. FGF stimulation of secretion was not detectable until 2 h of treatment. Intracellular hCG beta remained constant (23%) relative to total hCG beta (cell plus medium) as total hCG beta increased 3-fold, suggesting that FGF stimulated de novo hCG beta synthesis. Insulin significantly augmented the FGF-induced hCG beta stimulation without stimulating hCG beta production itself.
Oberbauer
A M
AM
Department of Physiology, Loma Linda University, California 92350.
Linkhart
T A
TA
Mohan
S
S
Longo
L D
LD
D002822:Choriocarcinoma / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000096:biosynthesis* / Q000378:metabolism; D018997:Chorionic Gonadotropin, beta Subunit, Human; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005346:Fibroblast Growth Factors / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007700:Kinetics; D009414:Nerve Growth Factors / Q000494:pharmacology; D010446:Peptide Fragments / Q000096:biosynthesis* / Q000378:metabolism; D015291:Transforming Growth Factors / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D007328:Insulin; D009414:Nerve Growth Factors; D010446:Peptide Fragments; D005346:Fibroblast Growth Factors; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D015291:Transforming Growth Factors