Comparative tissue distribution and excretion of [1-14C]acrylamide in beagle dogs and miniature pigs

Male beagle dogs and miniature pigs were given acrylamide in the diet for 3-4 wk at a dosage of 1 mg/kg/day. They were then given [1-14C]acrylamide as a single oral dose of 1 mg/kg. The animals were killed 6 hr or 1, 2, 4 or 14 days after administration of the radioactive compound and tissues were analysed for radioactivity. The radiolabelled material was distributed to a major extent in muscle tissue in both species (31-35% of the dose at 6 hr and 5-7% at 14 days). Although the nervous system is the primary target for acrylamide monomer toxicity, less than 1% of the administered 14C was found in the brain in both species. No neurotoxic signs were evident during the exposure period at the dosage used. Analysis of discrete areas of the brain for radioactivity revealed that the levels of penetration of [1-14C]acrylamide in brain paralleled the vascularization pattern of the tissues. Approximately 60% of the administered radiolabel was excreted in the urine in both species and smaller amounts were excreted in the faeces. However, recovery in the faeces was higher in pigs (c. 25%) than in dogs (c. 7%) and this and the considerably higher levels demonstrated in the gastro-intestinal tract of the pigs indicated that the absorption of acrylamide was more rapid and more extensive in dogs than in pigs.