Excretion, distribution, and tissue storage of a carbon-14-labeled photoconversion product of 14C-dieldrin

Abstract

Subacute levels ( 5 pg per day) of 14C-labeled dieldrin or photodieldrin were administered to young adult rats of both sexes for as long as 12 weeks. Photodieldrin was given both orally and intraperitoneally ; dieldrin was given by stomach tube only. Urinary, fecal, and total excretion patterns as well as tissue distribution and storage of 'T-labeled residues were determined. From 59.2 to 64.7z of the 14C-activity administered as photodieldrin was excreted in the urine and feces of male rats and 45.9 to 49.0 z was found in the excreta of females. A total of 63.6z of the 14C-activity from dieldrin was excreted by male rats and only 37.0z by females. Analysis of various tissues showed that from 3 to 10 times more 14C-activity was retained by females as compared to males after photodieldrin, regardless of the route of administration. A similar sex difference in tissue levels was found after administration of dieldrin. Adipose tissue was the principal storage site of both dieldrin and photodieldrin in female rats and of dieldrin in male rats. Extremely high levels of 14C-activity were detected in the kidneys of male rats receiving photodieldrin. D ieldrin (1,2,3,4,10,10-hexachloro-exo-6,7-epoxy-l,4,4a, 5,6,7,8,8a -octahydro -1,4 -endo, exo -5,8 -dimethanonaphthalene), when present as deposits o n grass and subjected to sunlight, undergoes photodecomposition (Roburn, 1963). Acute toxicity studies by Rosen and Sutherland (1967) and by Brown er a/. (1967) have suggested that the photoconversion product of dieldrin (photodieldrin) is more toxic to certain mammalian species than the parent compound. Because of these findings, it became of interest to study excretion and storage patterns after administration of subacute levels of photodieldrin to rats of both sexes and to compare these patterns with those found after administration of dieldrin under the same conditions. Since the desired dose levels were low, it was advantageous to use radiolabeled compounds. METHODS AND MATERIALSReagents and Apparatus. l?C-photodieldrin was prepared by ultraviolet irradiation of IT-dieldrin (NuclearChicago Corp.) using a method recently described by Benson (1969). Both compounds were judged to be essentially free of interfering substances by gas-liquid and thin-layer chromatographic techniques. The specific activity of the I4C-dieldrin used was 5.3 mCi per mmole, and the 14CC-photodieldrin was diluted with pure unlabeled photodieldrin to a specific activity of 4.3 mCi per mmole in order to provide enough material to complete the studies as planned. Both compounds were dissolved in acetone and stored at -20" C in the dark. At the time of administration, the acetone was evaporated and the compounds were redissolved in corn oil.All radioactivity measurements were made with a Packard Model 3375 liquid scintillation spectrometer, using a scintillation phosphor prepared by dissolving 4.0 g of 2,5-diphenyloxazole (PPO, Packard Instrument Co.) and 0.100 g of 1,4-bis-[2-(4-methyl-5-phenyloxolyl)] benzene (DMPOPOP, Packard Instrument Co.) in a mi...

Fate of [14C]photoheptachlor in rabbits

“…Acetone extracts of feces during the period of study did not show even trace amounts of radioactivity at any time, suggesting that the disposition of photoheptachlor takes place exclusively through the kidneys. This mode of excretion resembles that reported for photodieldrin in rabbit and monkey (Reddy and Khan, 1975;Nohynek et al, 1978) but differs from that of photodieldrin in rat (Dailey et al, 1970) where the major part of the label is passed through feces. It should, however, be pointed out that complete absence of radioactivity in feces of rabbits treated with [14C] photoheptachlor may be due to two reasons:…”

Metabolism, excretion, and tissue distribution of carbon-14-labeled photodieldrin in male rabbits, following single oral and intraperitoneal administration

“…Therefore, studies of its metabolism in various animals are of significant importance. Limited studies of the in vivo metabolism and distribution of photodieldrin in rats (Dailey et al, 1970;Klein et al, 1970;Dailey et al, 1972) and in vitro metabolism by mixed-function oxidase of various animals (Reddy and Khan, 1974) revealed that there was a species and sex difference in its metabolism. As photolysis of aldrin and dieldrin occurs on plant surfaces the effect of photodieldrin on herbivorous animals is of ecological significance.…”

Urinary metabolites of [14C] photodieldrin in male rabbits

“…Photodieldrin, an environmental "terminal residue" of the commonly used insecticides aldrin and dieldrin (Rosen et al, 1966;Khan et al, 1974), is considerably persistent in the environment (Suzuki et al, 1974;Reddy and Khan 1975a). It is metabolized by some insects (Khan et al, 1969; Reddy and Khan, 1977) and mammals (Klein et al, 1969(Klein et al, , 1970(Klein et al, , 1973Dailey et al, 1970Dailey et al, , 1972Khan, 1974, 1975b) to lipophilic and hydrophilic metabolites. Oral and intraperitoneal treatment of male rabbits resulted in excretion of about 50% (55% when intraperitoneally and 48.5% when orally administered) of the administered dose in urine and only 3% in feces in 9 days (Reddy and Khan, 1975b).…”