Using mouse everted whole small intestine 7 days after a single dose of Phenoclor DP6 (hexachlorobiphenyl) at 1.0 g kg-1 body wt, absorption of D-glucose decreased significantly, probably owing to toxic traces of pentodicholobenzofuran in the PCB preparation and not its high chlorine content. D-glucose tissue accumulation decreased. The serosal fluid transfer also fell but not the gut fluid uptake. D-glucose absorption and fluid transfer remained unchanged following doses of other Phenoclor and Pyralene (PCB) compounds. 2. Using DP6, malabsorption of D-glucose and impaired serosal fluid transfer were not evident 7 days after a single dose of 0.1, 0.25 and 0.50 g kg-1 body wt. One to 21 days after a single dose (1.0 g kg-1 body wt) of DP6, D-glucose absorption and serosal fluid transfer decreased from 3 to 14 days but thereafter became normal. 3. Although absorption of D-galactose, D-glucose following membrane hydrolysis of D-maltose, and L-arginine, L-histidine, L-ornithine and L-proline decreased slightly 7 days after a single dose of Phenoclor DP6,the results were not significant, nor were changes in fluid transfer. 4. Following Phenoclor DP6-treatment, D-glucose malabsorption was abolished by an exogenous energy supply (D-mannose). DP6 affected intracellular metabolism and not the glucose carrier at the membrane brush border. 5. The body-weights and fresh small intestinal weights of mice treated with different PCBs remained unchanged after seven days. The histology of the small intestine showed minimal changes.
