Endogenous insulin-like growth factors regulate the proliferation of TSH-independent mutants derived from FRTL5 cells.
TSH-independent mutant clones (M cells) derived from FRTL5 cells, proliferate vigorously in the absence of TSH. The growth of M cells is stimulated by IGF-I in a dose-dependent fashion, but it is not influenced by TSH. Sm1.2, an antibody against IGF-I cross-reacting with IGF-II, significantly decreases basal DNA synthesis in the M cells. Binding of 125I-IGF-I to M cells is significantly lower than that to FRTL5 cells. M cells produce in their culture medium IGF-like peptides which appear to influence their basal DNA synthesis and the availability of type I receptors to bind exogenous IGF-I.
Chieffi
P
P
CEOS/CNR, Dipartimento di Biologia e Patologia Cellulare e Molecolare Luigi Califano, Università di Napoli Federico II Naples, Italy.
Picascia
A
A
Stanzione
R
R
Villone
G
G
Tramontano
D
D
D000818:Animals; D002417:Cattle; D002455:Cell Division; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000378:metabolism* / Q000494:pharmacology; D008934:Mitogens / Q000378:metabolism / Q000494:pharmacology; D009154:Mutation; D051381:Rats; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D013961:Thyroid Gland / Q000166:cytology*; D013972:Thyrotropin
D008934:Mitogens; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013972:Thyrotropin; D004247:DNA; D017526:Receptor, IGF Type 1