Intestinal absorption and metabolism of retinoyl beta-glucuronide in humans, and of 15-[14C]-retinoyl beta-glucuronide in rats of different vitamin A status.

In order to prove the hypothesis that humans and animals with adequate vitamin A status do not absorb and metabolize orally administered all-trans retinoyl beta-glucuronide, unlabeled retinoyl glucuronide (0.1 mmol) was orally dosed to fasting well-nourished young men. Neither retinoyl glucuronide nor retinoic acid, a possible metabolite, appeared in the blood within 12 h after ingestion.