“…The amounts of 7-methylguanine observed in MMII-treated rats and mice were less than expected for a more proximal intermediate in the methylation pathway. Dost (1979) has recently shown that 75% of a aose of I mmole hydrazine per kg body weight was excreted by rats within 48 hours as expired nitrogen gas and as hydrazine or hydrazine conjugate(s) in the urine. Less than 100% of administered hydrazine, then, would be available for conversion to MMI in vivo.…”