Shimizu Y, Ida S, Naruto H, Urata G
J Lab Clin Med. 1978 Nov;92(5):795-802.
Excretion of porphyrins into bile and urine after intravenous injection of delta-ALA was studied in three patients with catheters inserted into the bile duct because of biliary obstruction and in two healthy volunteers. Excretion of porphyrins into bile increased in response to increasing doses of delta-ALA--up to 18 mumol/kg. On the other hand, excretion into urine reached a constant rate at 2 to 4 mumol/kg delta-ALA and did not increase further with larger doses. These findings suggest that transport of porphyrins across the liver cell membrane to the blood must be an important factor in determining the rate of excretion into the urine. After administration of delta-ALA,excretion of coproporphyrin III into urine increased more than that of coproporphyrin I. As a result, the former was the predominant form of urinary coproporphyrin. When radioactive delta-ALA was administered intravenously, far greater radioactivity was recovered in urine as coproporphyrin III than as coproporphyrin I. These results indicate that only a small portion of urinary coproporphyrin I is derived from the liver. A possible source of coproporphyrin I may be erythropoietic tissues, since the amount of urinary coproporphyrin I was considerably decreased in patients with severely suppressed erythropoiesis.
对3例因胆道梗阻而在胆管插入导管的患者及2名健康志愿者，研究了静脉注射δ-氨基-γ-酮戊酸（δ-ALA）后卟啉在胆汁和尿液中的排泄情况。随着δ-ALA剂量增加（高达18μmol/kg），胆汁中卟啉的排泄量增加。另一方面，当δ-ALA剂量达到2至4μmol/kg时，尿液中卟啉的排泄率达到稳定，更大剂量时不再增加。这些发现表明，卟啉跨肝细胞膜向血液的转运必定是决定尿液排泄率的一个重要因素。给予δ-ALA后，尿中粪卟啉原III的排泄增加幅度大于粪卟啉原I。结果，前者成为尿中粪卟啉的主要形式。静脉注射放射性δ-ALA后，尿液中以粪卟啉原III形式回收的放射性远多于粪卟啉原I。这些结果表明，尿中粪卟啉原I仅有一小部分来自肝脏。粪卟啉原I的一个可能来源或许是造血组织，因为在红细胞生成严重受抑的患者中，尿中粪卟啉原I的量显著减少。
