Table 1.

Overall and gene-specific repair of O⁶-alkylguanines in the DNA of mammary gland after exposure to MeNU or EtNU in vivo, and effect of MGMT inhibition by O⁶-BeGua

O6-BeGua	t1/2 (hr)
	O6-MeGua		O6-EtGua
	−	+	−	+
Genomic DNA	40	>48*	48	>48†
IgE	48	>48*	50	>48‡
H-ras	36	>48*	2.5	2.6
β-actin	45	>48*	2.4	2.4

t_1/2 values indicate the time periods required for removal of 50% of input O⁶-alkylguanines in DNA. 

^*<10%,  

^†26%, and  

^‡20% of input O⁶-alkylguanines repaired in the presence of O⁶-BeGua for 48 hr.