DISPOSITION OF INGESTED OLESTRA IN WEANLING MINIPIGS

The disposition of ingested olestra in Hanford mini-pigs was examined by following a single oral gavage dose of radiolabelled (U-C-14-sucros e) olestra. Eight dosed animals (four/sex) and one undosed animal were killed 1, 3 and 7 days after dosing, and tissues were collected and c ounted. Urine and faeces were collected continuously and counted. Tiss ue lipids were extracted and analysed for intact radiolabelled olestra by size exclusion chromatography. Sucrose will be excreted in urine i f olestra is absorbed and metabolized. Mean recovery of radiolabel was 96.6% of the administered dose. Of the recovered radiolabel, more tha n 99.4%, on average, was not absorbed and found in faeces, or cage and animal wash solutions. The absorbed radiolabel (0.6%), was distribute d across the carcass, all tissues and blood, or excreted in urine. Thi s radiolabel primarily came from the metabolism of glucose and fructos e resulting from the hydrolysis of the trace levels of penta- and lowe r sucrose esters present in the test material. No radiolabel was found in the olestra-containing fraction of liver lipids, the primary measu re of absorbed and non-metabolized olestra, at a detection limit of 0. 0002% of dose. A conservative estimate of the amount of C-14-sucrose e xcreted in the urine was 0.0012%. The total absorption of intact olest ra was thus less than 0.0014% of the dose, the sum of the two measures . These results indicate that intact olestra is essentially not absorb ed by the weanling mini-pig, an animal with a young developing gastroi ntestinal tract similar to that of young children (2-5 yr). Copyright (C) 1996 Elsevier Science Ltd.