Table 2.

Time course incorporation of L-[¹⁴C(U)]-Leucine into protein in serially subcultured human fibroblasts (cpm/μg protein)

Hours post-subculture	Subculture passage
	P5	P25	P35
12	18.2 ± 0.35	7.1 ± 0.24	8.3 ± 0.30
24	21.2 ± 0.53	6.8 ± 0.25	8.6 ± 0.29
48	20.6 ± 0.51	8.3 ± 0.26	11.4 ± 0.38
72	21.3 ± 0.58	13.1 ± 0.40	15.2 ± 0.41
96	20.9 ± 0.50	19.7 ± 0.48	17.3 ± 0.43
120	21.4 ± 0.55	21.3 ± 0.54	20.5 ± 0.51
144	20.5 ± 0.57	20.9 ± 0.56	21.2 ± 0.58

Values are means ± SD of duplicate determinations in six subcultures.