Growth rate determines activity of porphobilinogen deaminase both in nonmalignant and malignant cell lines

PBGD activity and growth rate were determined in cultures of rat embryo fibroblasts, nontransformed and MLV/MS transformed fibroblastic cell lines; NIH-3T3 cells, and in a mouse lymphosarcoma cell line [L-929]. The two parameters examined correlate positively (P less than 0.001). The results of this investigation would seem to indicate clearly that porphobilinogen deaminase activity is related to growth. However, these experiments do not rule out the possibility that malignant transformation per se also causes changes in porphobilinogen deaminase activity.