Raymond L. Blakley
Oct 1, 1952
Citations
0
Influential Citations
4
Citations
Journal
The Biochemical journal
Abstract
The data on elimination of ethyl carbamate (Boyland & Rhoden, 1949; Skipper et al. 1951) indicated that the time for 50% elimination was of the order of 12 hr. for normal rats or mice and 24 hr. for tumour-bearing animals. The present data indicate that methyl carbamate, like ethyl carbamate or ethanol, is not concentrated by the kidney, so that elimination must be mainly by metabolism. Methyl carbamate appears to be metabolized at about half the rate of ethyl carbamate. The relationship ofmetabolism of the methyl and ethyl carbamates to their biological action is difficult to understand. If the radiomimetic action were due to hydrolysis of the carbamate, then the slower metabolism of methyl carbamate should be compensated for by increase of the dose. This, however, is not the case. If the carcinogenic action of urethane were due to slow liberation of ethanol oxidized to acetaldehyde within the tissues then methanol would be expected to be as effective, as formaldehyde has been found to be mutagenic (Rapoport, 1946). The discovery that ethyl carbamate is a much more effective inhibitor of transmethylation reactions than is methyl carbamate (McKinney, 1950) suggests that such inhibition may be concerned with the radiomimetic effects produced by urethane.