Binding of ethylene oxide in spermiogenic germ cell stages of the mouse after low-level inhalation exposure.
Mice received inhalation exposures of 3H-labeled ethylene oxide (EtO) gas at levels from 0.65 to 3.2 parts per million-hours (ppm-hr), which are below the exposure limits currently allowed for humans. Subsequently, spermatozoa were recovered from the reproductive tracts of the animals over a two-week period and assayed for the amount of bound EtO. A strong increase in the level of EtO binding occurred in late spermatid stages; these stages are also genetically sensitive to the action of EtO. The maximum binding of EtO in late spermatids amounted to 6 X 10(3) alkylations/sperm head/ppm-hr of exposure. Alkylation of the DNA within the sperm accounted for a very small fraction of the total sperm head alkylation, averaging about 20 DNA alkylations per sperm per ppm-hr of exposure over the two-week period. However, alkylation of protamine, a protein unique to sperm cells, was found to be correlated with total sperm head alkylation and accounted for nearly all of the EtO binding. Protamine alkylation appears to be a significant cause of EtO-induced genetic damage in spermiogenic cells of the mammal.
Sega
G A
GA
Biology Division, Oak Ridge National Laboratory, Tennessee 37831.
Owens
J G
JG
D000280:Administration, Inhalation; D000478:Alkylation; D000818:Animals; D004247:DNA / Q000187:drug effects; D004249:DNA Damage; D005027:Ethylene Oxide / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D051379:Mice; D011479:Protamines / Q000378:metabolism; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism
D011479:Protamines; D004247:DNA; D005027:Ethylene Oxide