抄録
Retinoic acid, when dissolved in 0.1N KOH and diluted with 0.1M phosphate buffer (pH 8), was proved to be stable on heating or standing for days at 37℃, if light was intercepted. Retinoic acid added in the homogenate of animal tissues or in urine or feces, can be extracted by 70% ethanol. The extract after the centrifugation was diluted by 0.1M phosphate buffer and extracted by ligroin. Retinoic acid in the ligroin layer was purified by the transfer to 0.1N KOH in 50% ethanol and the re-extraction by ligroin then retinoic acid was estimated by E value at 355mμ or 74% sulfuric acid color reaction. Retinoic acid when 3 mg were orayll given to rats, was found in the feces for 24 hours to the extent of 3-15% of the dosage but was unable to be detected in the urine. Retinoic acid, when 1.2mg were infused in ligated small intestine of rats, was recovered from the intestine after one hour only to the extent of 33% of the dosage and the retinoic acid in livers and kidneys was estimated as 46 and 17μg even at the highest peak after 2 hours. It was concluded from the repeated infusion experiments into ligated intestines of rats that retinoic acid was so quickly metabolized and decomposed in animals after absorption from the intestine that it was hardly detected in animal tissues and feces.
