Abundant excretion of human growth hormone by recombinant-plasmid-transformed monkey kidney cells

A recombinant plasmid was constructed permitting the efficient synthesis of human growth hormone (hGH) in monkey cells. The plasmid contains the cDNA sequence of the hGH precursor and controlled by the SV40 early promoter, an intron, and the poly(A)-addition site of the mouse alpha-globin gene. To permit selection of transformed cells, a selectable marker (xanthine-guanine phosphoribosyl transferase; XGPRT) was also introduced into this plasmid. Transformation of an established monkey kidney cell line (VERO) permitted the isolation of cell lines excreting hGH. One of these strains (VEH 1) excreted hGH up to 5.6 micrograms per 10(6) cells per 24 h during exponential growth.