TABLE 2.

Growth rates of Ras-expressing cells^a

Cell line	Doubling time (h) in medium
	3H (+TSH)	2H (−TSH)
WRT	34.2 ± 2.4	62.7 ± 3.6
RasV12	36.7 ± 1.9	26.6 ± 2.7
RasS35	37.2 ± 4.1	32.0 ± 6.2
RasG37	27.5 ± 2.3	35.7 ± 3.3

^aThe P value for the Ras^G37 trials was <0.025, while the P value for the Ras^V12 trials was <0.005. The effects of TSH on growth rate in Ras^S35 cells were not statistically significant although they were consistently observed. The results shown are representative of four independent experiments performed with similar results.