BHC (Benzene hexachloride) (1,2,3,4,5,6-Hexachlorocyclohexane) 
(Lindane = y-BHC) 
red 
Be 
cae 
i 
Radiochemical methods used to study the fate of y-BHC in flies showed 
that no respired gases contained cuN, Although most of the radioactivity 
could be extracted by carbon tetrachloride, an unextracted residual activity 
remained in both resistant and normal flies. In addition to pentachloro- 
cyclohexene, some water-soluble metabolites were found (157, 158, 159, 160, 
162, 179, 712, 1114, 1357). Other studies indicated, however, that the 
first step in the metabolism of y-BHC was the removal of one chlorine atom 
and the formation of a C-S bond, followed by loss of additional chlorine 
atoms and the formation of all six isomers of dichlorothiophenol (163). 
Anopholes gambiae were also able to convert a- and y-BHC to water-soluble 
compounds (161). Recently, two isomers of pentachlorocyclohexene were 
obtained after exposure of houseflies to y-BHC (1587). 
When y-BHC was fed to dairy cows (1465), no pentachlorocyclohexene 
was found in the milk. Studies with dogs, rabbits, and rats indicated a 
rapid breakdown of BHC into 1,2,4-trichlorobenzene and other compounds of 
unknown structure (40, 183, 304, 825, 1264). When labeled o- and y-BHC 
was administered to rats intraperitoneally, a high concentration of radi- 
ating material was present in the central nervous system. Both isomers 
were dechlorinated in vivo and converted to water soluble compounds which 
were excreted by the kidneys (824). In rats, urinary excretion reached a 
peak on the 5th to 8th day after administration and BHC was not detected 
after 17-18 days (1252, 1551). A single oral administration of 50 or 
100 mg of y-BHC/kg body weight of rats increased levels of total glucuronic 
acid excreted in urine during 14-15 days by a daily average of 1.5 mg, and 
organic sulfur compounds by 35-58% during 13-14 days. Thin layer and silicic 
acid column chromatography showed undecomposed y-BHC and 2 metabolites in 
urine and liver for 14 days after administration of the BHC (1251). 
y- and 6-1,3,4,5,6-pentachlorocyclohexene-1 were metabolized by rat 
and liver microsomes in the presence of NADPH, and 0, (711). In other 
studies, y-BHC and y-2,3,4,5,6-pentachlorocyclohex-l-ene were converted 
by rats into 2,3,5,- and 2,4,5-trichlorophenol and excreted in urine as 
free phenols, sulfates, and glucuronic acid conjugates. 2,4-Dichloro- 
mercapturic acid was also isolated (570). The products found in these 
studies resemble those in the metabolism of 1,2,4-trichlorobenzene in 
rabbits (742), and it would appear that the metabolism of y-BHC proceeds 
via y-2,3,4,5,6-pentachlorocyclohex-l-ene to 1,2,4-trichlorobenzene. In 
other studies, a-BHC gave rise to 2,4,6-trichlorophenol (823). 
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