Fig. 2.

C18R PPTH-transfected cells exhibit abnormal intracellular accumulation and reduced secretion of PTH. (A) HEK293 cells were transfected with wild-type or C18R PPTH-expressing cDNAs. Seventy-two hours after transfection, the cells were fixed and immunostained with polyclonal antibody against PTH, followed by TRITC-conjugated (red) secondary antibody and visualized by fluorescence microscopy. Nuclear staining with DAPI (blue) accounted for the total number of cells in the field. (B) Concentration of the secreted PTH in the media from the wild-type or C18R PPTH-transfected cells were measured by competitive ELISA using standard PTH peptide provided with the kit. The actual values were normalized with respect to total cell protein, and the data are presented as mean ± SD of three independent media samples.