Inhibition of synthesis of alpha-fetoprotein by glucocorticoids in cultured hepatoma cells.
alpha-Fetoprotein (AFP) synthesis was studied in the presence and absence of glucocorticoids in rat hepatoma Mc-A-RH-7777 cells. Radioimmunoassay of media from cell cultures grown in the presence of glucocorticoid (dexamethasone or cortisol) showed a reduction in AFP, an increase in albumin, and no significant change in transferrin accumulation, as compared to controls. Labeling experiments with L-[35S]methionine indicated that in both cells and media of dexamethasone-treated cultures there was a 50--80% reduction in polypeptide precipitated by anti-AFP serum, as compared with controls; no change was seen in polypeptide precipitated by anti-transferrin serum. Pulse and pulse-chase experiments demonstrated that dexamethasone inhibited the synthesis of AFP but not its secretion. The half-time for secretion of AFP in the presence and absence of dexamethasone was 43 min.
D000418:Albumins / Q000096:biosynthesis; D000818:Animals; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology*; D006854:Hydrocortisone / Q000494:pharmacology*; D007700:Kinetics; D008114:Liver Neoplasms, Experimental; D008715:Methionine / Q000378:metabolism; D051381:Rats; D014168:Transferrin / Q000096:biosynthesis; D000509:alpha-Fetoproteins / Q000096:biosynthesis*
D000418:Albumins; D014168:Transferrin; D000509:alpha-Fetoproteins; D003907:Dexamethasone; D008715:Methionine; D006854:Hydrocortisone