Dynamics of absorption, metabolism, and excretion of 5-aminolevulinic acid in human intestinal Caco-2 cells

Kei Saito, Tohru Fujiwara, Urara Ota, Shunsuke Hatta, Satoshi Ichikawa, Masahiro Kobayashi, Yoko Okitsu, Noriko Fukuhara, Yasushi Onishi, Masahiro Ishizuka, Tohru Tanaka, Hideo Harigae

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


5-Aminolevulinic acid (ALA) is a precursor for the biosynthesis of porphyrins and heme. Although the oral administration of ALA has been widely applied in clinical settings, the dynamics of its absorption, metabolism, and excretion within enterocytes remain unknown. In this study, after enterocytic differentiation, Caco-2 cells were incubated with 200 µM ALA and/or 100 µM sodium ferrous citrate (SFC) for up to 72 h. Both ALA and the combination of ALA and SFC promoted the synthesis of heme, without affecting the expression of genes involved in intestinal iron transport, such as DMT1 and FPN. The enhanced heme synthesis in Caco-2 cells was more pronounced under the effect of the combination of ALA and SFC than under the effect of ALA alone, as reflected by the induced expression of heme oxygenase 1 (HO-1), as well as a reduced protein level of the transcriptional corepressor Bach1. Chromatin immunoprecipitation analysis confirmed Bach1 chromatin occupancy at the enhancer regions of HO-1, which were significantly decreased by the addition of ALA and SFC. Finally, Transwell culture of Caco-2 cells suggested that the administered ALA to the intestinal lumen was partially transported into vasolateral space. These findings enhance our understanding of the absorption and metabolism of ALA in enterocytes, which could aid in the development of a treatment strategy for various conditions such as anemia.

Original languageEnglish
Pages (from-to)105-111
Number of pages7
JournalBiochemistry and Biophysics Reports
Publication statusPublished - 2017 Sept


  • 5-Aminolevulinic acid
  • Bach1
  • Caco-2 cell
  • Heme oxygenase 1

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry


Dive into the research topics of 'Dynamics of absorption, metabolism, and excretion of 5-aminolevulinic acid in human intestinal Caco-2 cells'. Together they form a unique fingerprint.

Cite this