Rapid deconjugation of SN‑38 glucuronide and adsorption of released free SN‑38 by intestinal microorganisms in rat

  • Authors:
    • Akira Takakura
    • Akinobu Kurita
    • Takashi Asahara
    • Masanori Yokoba
    • Michiko Yamamoto
    • Shinichiro Ryuge
    • Satoshi Igawa
    • Yukitoshi Yasuzawa
    • Jiichiro Sasaki
    • Hirosuke Kobayashi
    • Noriyuki Masuda
  • View Affiliations

  • Published online on: December 9, 2011     https://doi.org/10.3892/ol.2011.519
  • Pages: 520-524
Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

One of the dose‑limiting toxicities of irinotecan hydrochloride (CPT‑11) is delayed‑onset diarrhea. CPT‑11 is converted to its active metabolite, SN‑38, which is conjugated to SN‑38 glucuronide (SN‑38G). SN‑38G excreted in the intestinal lumen is extensively deconjugated by bacterial β‑glucuronidase, resulting in the regeneration of SN‑38, which causes diarrhea. However, the deconjugation of SN‑38G by the intestinal microflora remains to be clarified. This study aimed to investigate the microbial transformation of SN‑38G by an anaerobic mixed culture of rat cecal microorganisms. Concentrations of SN-38G and SN-38 were then determined using high-performance liquid chromatography. Complete deconjugation of SN‑38G to SN‑38 in the mixed cultures was observed within 1 h of incubation, with 62.7% of the added SN‑38G being found in the supernatant. Approximately 80.4% of the SN‑38 in the supernatant was bound to protein, and the remaining 19.6% was detected as active free SN‑38. In total, only 12.3% (19.6 x 62.7%) of the SN‑38G added to the test tube was found in the supernatant in the ultrafiltrable free form, indicating that approximately 90% of the SN‑38G added to the growth medium either remained adsorbed onto the pelleted fraction or occurred in a protein‑bound form in the supernatant. The remaining 10% of the SN‑38G added to the growth medium existed in the unbound form, the form capable of causing damage to the intestinal membrane. In conclusion, these results indicated that the greater part of the SN‑38 produced from SN‑38G by the action of bacterial β‑glucuronidase is rapidly adsorbed onto intestinal bacterial cell walls or dietary fibers in pelleted fraction, and only 10% remains in the ultrafiltrable unbound form in the intestinal luminal fluid.
View Figures
View References

Related Articles

Journal Cover

March 2012
Volume 3 Issue 3

Print ISSN: 1792-1074
Online ISSN:1792-1082

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Takakura A, Kurita A, Asahara T, Yokoba M, Yamamoto M, Ryuge S, Igawa S, Yasuzawa Y, Sasaki J, Kobayashi H, Kobayashi H, et al: Rapid deconjugation of SN‑38 glucuronide and adsorption of released free SN‑38 by intestinal microorganisms in rat. Oncol Lett 3: 520-524, 2012
APA
Takakura, A., Kurita, A., Asahara, T., Yokoba, M., Yamamoto, M., Ryuge, S. ... Masuda, N. (2012). Rapid deconjugation of SN‑38 glucuronide and adsorption of released free SN‑38 by intestinal microorganisms in rat. Oncology Letters, 3, 520-524. https://doi.org/10.3892/ol.2011.519
MLA
Takakura, A., Kurita, A., Asahara, T., Yokoba, M., Yamamoto, M., Ryuge, S., Igawa, S., Yasuzawa, Y., Sasaki, J., Kobayashi, H., Masuda, N."Rapid deconjugation of SN‑38 glucuronide and adsorption of released free SN‑38 by intestinal microorganisms in rat". Oncology Letters 3.3 (2012): 520-524.
Chicago
Takakura, A., Kurita, A., Asahara, T., Yokoba, M., Yamamoto, M., Ryuge, S., Igawa, S., Yasuzawa, Y., Sasaki, J., Kobayashi, H., Masuda, N."Rapid deconjugation of SN‑38 glucuronide and adsorption of released free SN‑38 by intestinal microorganisms in rat". Oncology Letters 3, no. 3 (2012): 520-524. https://doi.org/10.3892/ol.2011.519