SYNTHESIS AND RELEASE OF GLYCOSYLATED PROLACTIN IN TRANSFECTED CELLS WITH HUMAN PROLACTIN COMPLEMENTARY DEOXYRIBONUCLEIC-ACID

To analyze how the synthesis and release of glycosylated PRL (G-PRL) i s regulated, we transfected human PRL complementary deoxyribonucleic a cid (cDNA) into three different cell lines consisting of GH3 cells tha t originated in rat pituitary tissue, Chinese hamster ovary cells, and COS-1 cells generated from monkey renal tissue. S-35-labeled PRLs pro duced by the cells were immunoprecipitated with anti-human PRL antiser um, and the ratios of G-PRL to total PRL were compared. PRLs of 23 kDa and 25 kDa were detected in the cell lysate and medium. The 25-kDa PR L was confirmed to be a glycosylated form by endoglycosidase treatment s. The ratios of G-PRL/total PRL were 0.17-0.33, which were similar in lysates and media and among different cell lines. Pulse-chase experim ents revealed that the autonomaous secretion rates of G-PRL and non-gl ycosylated PRL were almost identical. These results indicate that synt hesis and secretion kinetics of human PRL may not be affected by its g lycosylation in the cells transfected with PRL cDNA.