Estrous cycle modification of rat uterine DNA alkylation by N-methyl-N-nitrosourea.
The present study was designed to determine whether the stage of the estrous cycle at the time of N-nitroso-N-methylurea (NMU) presentation altered DNA adduct formation and repair in the rat uterus. In uterus the rate of O6-methylguanine (O6-meGua) and 7-methylguanine (7-meGua) formation and the total yield of adducts was estrous cycle dependent. Uterine DNA from rats injected with NMU on diestrus formed O6-meGua and 7-meGua more rapidly and had significantly higher adduct levels than those rats injected on proestrus or estrus. Repair of O6-meGua and 7-meGua was also significantly faster between 1 and 24 h post-NMU in uterine DNA isolated from rats injected on diestrus compared to those injected on proestrus or estrus.
Braun
R J
RJ
Division of Surgical Oncology, University of Illinois, Chicago 60612.
Ratko
T A
TA
Pezzuto
J M
JM
Beattie
C W
CW
D000478:Alkylation; D000818:Animals; D004249:DNA Damage; D004260:DNA Repair; D004971:Estrus; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D008770:Methylnitrosourea / Q000378:metabolism*; D051381:Rats; D013997:Time Factors; D014599:Uterus / Q000378:metabolism
D006147:Guanine; C008450:7-methylguanine; D008770:Methylnitrosourea; C008449:O-(6)-methylguanine