Ectopic production in serum-free media of the common alpha subunit of the glycoprotein hormones

Effect of media composition on the induction of chorionic gonadotropin by sodium butyrate in HeLa cells

Production of the glycoprotein hormone alpha-subunit by HeLa cells and its induction by sodium butyrate are dependent on the choice of culture medium. Under identical growth conditions it was found that subunit synthesis in the presence of butyrate was highest in RPMI 1640, lowest in Medium 199 (M199), and intermediate in minimum essential medium (MEM) and Waymouth's MB 752/1. Cell growth was similar in all media examined and was retarded in the presence of butyrate. Alkaline phosphatase activity was also lower in M199 than in RPMI 1640, although, in general, the magnitude of this difference was less than that for the hormone subunit. Incorporation of [1-14C]butyrate by HeLa cells was similar in both M199 and RPMI 1640, indicating that uptake and metabolism of the fatty acid were not significantly different under these conditions. In the presence of 3 mM butyrate, mixtures of RPMI 1640 and M199 gave intermediate levels of alpha-subunit and alkaline phosphatase compared to each medium alone. Intracellular levels of alpha-subunit as well as that of the culture medium were reduced in M199 compared to RPMI 1640 indicating that synthesis rather than secretion was altered.