Absorption, Distribution, Metabolism, and Excretion of Carbon-14-Labeled DDT by the American Cockroach, Periplaneta americana (L.)

• Main Author: Robbins, William E
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-1954
• Subjects: Biochemistry; Entomology
• ISBN: 9780496453887; 0496453882

The absorption, tissue distribution, metabolism, and excretion of p,p ′-C14- and 2-C14-ethane-labeled DDT and the tissue distribution and excretion of p,p′-C 14-labeled DDE in female American cockroaches, Periplaneta americana (L.), have been studied. The absorption studies snowed that DDT applied topically at the rate of 40 μgm. per roach is initially very rapidly absorbed (nearly 50 per cent in 24 hours) and after six days more than 95 per cent is absorbed. The internal distribution of p,p ′-C14- and 2-C14-ethane-labeled DDT, p,p′-C14-labeled DDT plus “Piperonyl cyclonene”, and p,p′-C14-labeled DDE in female American cockroaches has been determined 72 hours following topical application of sub-lethal doses of the compounds. Of the tissues dissected and assayed radiometrically, the foregut, hindgut plus malpighian tubules, and fat contained the greatest amount of radioactivity. The CO2 expired by roaches treated topically and injected with p,pμ-C14-labeled DDT was assayed radiometrically as EaCO3 to determine if the insecticide might be degraded to C 14O2. Less than one per cent of the DDT applied topically or injected was excreted as C14O2. The excretion of radioactivity in the feces of roaches treated topically with the same compounds used in the distribution studies summarized above has been determined. As much as 75 per cent of the DDT applied can be accounted for over a 24-day period. When the synergist “piperonyl cyclonene” is used with DDT it inhibits both the absorption and excretion of the DDT and/or its metabolic products. Colorimetric analyses of the fecal metabolites of roaches treated topically with p,p′-C14-labeled DDT indicated that the major portion of the metabolites was not due to DDT, DDE, or DDA. Paper chromatographic analyses of fecal metabolites of roaches treated topically with p,p′-C14- and 2-C14-ethane-labeled DDT showed that less than 10 per cent of the radioactivity in the feces was due to DDT, DDE, or DDA. In the case of both radioactive DDT compounds, about 80 per cent of the radioactivity in the feces is associated with one or more metabolites that contain the diphenyl-2-carbon moiety of the original molecules. Biological evaluation of the fecal metabolites, using house flies, demonstrated a lower toxicity and decreased ability to penetrate insect cuticle as compared with DDT. (Abstract shortened by UMI.)