No metabolites could be demonstrated after exposure of daphnia and 
fat head minnows to endrin (1180). In the presence of NADPH, , rat and 
rabbit liver microsomes converted isodrin to endrin (1069). 
c!4-labeled endrin was administered orally and intravenously to rats. 
Examination of collected urine indicated a major metabolite more hydrophyllic 
than endrin-~-identified as the keto analog of endrin-~and other hydrophyllic 
compound in lesser (about 5%) amount. These metabolites were identical with 
the NADPH,-liver homogenate metabolite (1069, 1575). 
On foliage endrin was less persistent than dieldrin. After one week, 
a small amount of the ketone isomer (II) of endrin was detected. This was 
not observed in later samples. The corresponding aldehyde (III) was present 
_to the extent of 15% of the total residue after seven weeks but was not 
detected four weeks later (618). After application of endrin to Brassica 
oleracea var. capitata, two metabolites were observed. One was identified 
as the endrin-ketone. This occurred in darkness or in the presence of light 
and with plant homogenates as well as the intact plant (1600). 
When isodrin !4C was applied topically to houseflies, the corresponding 
epoxide endrin and small amounts of a water-insoluble product which behaved 
as the ketone, a known rearrangement product of endrin, were recovered (186). 
Endrin was mt formed in tissues of heat-killed insects. Similarly, isodrin 
was converted to endrin by the American cockroach (Periplaneta americana L.) 
(546). Similar metabolic products were observed when Aspergillus flavus or 
mosquito larvae of Aedes aegypti were exposed to endrin (1575). Aerobacter 
aerogenes, Pseudomonas aeruginosa, and three unidentified marine organisms 
degraded endrin but no metabolites were identified (1561). 
UV irradiation of endrin gave rise to one main compound and smaller 
amounts of several others (1228). After isolation of two irradiation products, 
infra-red spectra showed these to be identical with ketone (II) [1,8- exo- 
9,10,11,11-hexachloropentacyclo-(6.2.1.1.2*6.02>/0'+»19,)dodecan-5-one] and 
aldehyde (III) [4,5,6,7,8,8-hexachlorohexahydro-4, 7-methano-3,5,6-me theno- 
indan-l-carboxaldehyde] isomers of endrin (1237). 
Endrin underwent thermal decomposition and isomerization beginning at 
about 90° to 100° C. Gas chromatography indicated about four compounds. By 
means of infra~red, one was identified as the ketone (II), 280-283° C (dec.); 
a second compound was the "cage" alcohol (IV), m.p. 330° C. An aldehyde (III) 
isomeric to (II) was also observed and identified after gas chromatography, 
infra-red, and elemental analysis (1159, 1160). Some spontaneous decomposition 
has also been observed (83). 
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