Pharmacodynamics of Dieldrin-C14 in Pheasants

Donald Wayne Lamb


The distribution, excretion, and metabolism of dieldrin-c14 in hen pheasants were studied. Eighteen laying hen pheasants were administered a gelatin capsule containing 1.4 mg or dieldrin labelled with 5.5 microcuries of carbon-14. Groups of three birds were killed at intervals of 2, 6, and 12 hours, and 3, 6, and 35 days following treatment. Concentrations of dieldrin residues in brain, fat, heart, liver, muscle, ovar;r, eggs, and feces were determined by gas chromatography and liquid scintillation counting. Dieldrin residues were present in tissues of one bird killed 2 hours after treatment. The highest average level of residues occurred in all tissues at the 6-hour interval. Fat contained the highest levels of residue with an average of 6.45 ppm at 6 hours and 1.72 ppm at 5 weeks after treatment. Liver had an average of 1.56 ppm at 6 hours and .33 at 5 weeks. Levels in brain, heart and muscle followed the same general decline pattern, but were not higher than .3 ppm at any time. Different sized ova removed from birds at the 6-day interval contained similar concentration of dieldrin residues indicating that the insecticide was incorporated into yolk at a constant rate. Three birds absorbed 85.6, 88.8, and 96.9 percent of the 1.4mg dieldrin treatment administered in a single gelatin capsule. Birds killed 5 weeks after treatment excreted 26.5, 21.5, and 18.2 percent of the dieldrin in their feces, and 11.5, 14.4 and 13.0 percent in their eggs. After the first 24 hours, levels excreted per day in the eggs and feces were relatively constant and averaged 9.07, 9.24, and 11.45 ug. Elimination in eggs and feces was 38.0, 35.9, and 28.2 percent and whole body sample analysis of the same birds showed they contained 34.6, 21.2, and 32.7 percent of the administered dieldrin after the 5 week period. Therefore, the recovery of the dieldrin-c14 was 72.6, 57.1, and 60.9 percent of the 1.4 mg treatment. Water soluble metabolites were found in the feces but not in egg yolks. No metabolites were found in the eggs or tissues after Florisil column extraction. The uniform decline of tissue residue concentration as residues were eliminated in eggs and feces indicated a dyr1amic equilibrium relationship between the tissues, eggs, and feces after the birds received a single treatment.