days to residues amounting to 11 and 32%, respectively, of the dose as 
op. Excretion of naphthyl and carbonyl labels was essentially complete 
with 95% and 99% of label respectively recovered. The methyl label was 
excreted to the extent of 88% and residues were detected in the intestinal 
tracts, carcasses, and organs (Knaak et al., 1965). 
In the urine, in addition to l-naphthol (Carpenter et al., 1961) 
l-naphthyl methylcarbamate N-glucuronide, l-naphthyl methylimidocarbonate 
O-glucuronide, 4-(methylcarbamoyloxy)-l-naphthyl glucuronide, 1-naphthyl 
glucuronide, l-naphthyl sulfate, 4-(methylcarbamoyloxy)-l-naphthyl sulfate, 
and 3 unidentified metabolites were found (Knaak et al., 1965). 
Rat liver microsomes degraded sevin into six known compounds and at 
least as many unidentified materials. The methyl group was modified to 
give l-naphthol-N-hydroxmethylcarbamate. Ring hydroxylation occurred to 
yield 4-hydroxy - and traces of 5-hydroxy-1l-naphthyl-N-methylcarbamate. 
There was some evidence that the 3,4-dihydroxy-3,4-dihydro analog was 
also formed. In addition to these materials, the hydrolysis product l- 
naphthol was found. Water-soluble fractions were obtained but not identified, 
These are probably conjugates of carbamates and their hydrolytis products 
and would be expected to consist of glucosiduronic acids, sulfates, mer- 
capturic acids, N-acetylmercapturic acids, and glucosides (Dorough et al., 
1963, 1964). After exposure of sevin to plasma of 15 different animals, 
l-naphthol was identified in each case (Casida and Augustinsson, 1959). 
Sevin, in acetone, topically applied to milkweed bug nymphs was ab- 
sorbed fairly rapidly but labeled products were excreted inefficiently. 
Only unchanged sevin and a very polar unidentified metabolite were dem- 
onstrated. 
144 
