Capacity-limited sulfation of chemicals is thought to be due to the limited availability of 3'-phosphoadenosine 5'-phosphosulfate (PAPS), the cosubstrate for sulfation, which in turn is limited by the availability of its precursor, inorganic sulfate. Because this concept evolved from experimental data obtained from rats, and species differences have also been reported on acetaminophen (AA) sulfation, this study examined the effects of AA on PAPS and sulfate concentrations in mice, another widely used experimental animal. AA lowered serum and liver sulfate concentrations approximately 50% in mice. However, contrary to observations in rats, AA (0-600 mg/kg i.p.) did not decrease hepatic PAPS concentrations in mice. In summary, these studies demonstrate that AA decreases serum and liver sulfate concentrations, but does not decrease hepatic PAPS concentrations in mice. These data indicate that 1) hepatic sulfation of high dosages of AA in mice is not limited by the availability of PAPS, and 2) there are significant species differences in the regulation of AA sulfation between rats and mice.