Sprague-Dawley microsomes (50 μg of protein) were incubated with 0.1 mM [³H]atRA and 4 mM UDP-GlcUA for 30 min at 37°C. After incubation, reactions were either stopped (control) or incubated for an additional 2 hr with 100 units of β-glucuronidase, in the absence or presence of 12.5 mM saccharolactone. The results are expressed as the mean ± SD of at least two separate duplicate determinations. The numbers in parentheses give the percentage of the control recovery.