Mechanisms of Intestinal Absorption of the Antibiotic, Fosfomycin, in Brush-Border Membrane Vesicles in Rabbits and Humans

Takayuki Ishizawa, Kaoru Hosoi, Ikumi Tamai, Tetsuya Terasaki, Akira Tsuji

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


In order to clarify the mechanism of intestinal absorption of an antibiotic, fosfomycin (FOM), the uptakes of FOM by rabbit and human small intestinal brush-border membrane vesicles (BBMV) were studied. The initial uptake of FOM by BBMV at 15 s was saturable at a higher concentration of FOM. The kinetic parameters at 37 �C of the saturable uptake expressed by the Michaelis-Menten equation were Kt = 5.17 mM and /max = 3.88 nmol/15 s/mg protein for rabbits, and Kt = 4.03 mM and Jmax = 1.90 nmol/15 s/mg protein for humans. The most efficient uptake was observed in the presence of both inward-directed Na + - and H +-gradients in both mammals. The uptake of FOM was inhibited by inorganic phosphate, FOM glycol which is a degradation product of FOM in the gastric juice and specific inhibitors of phosphate transport such as arsenate and phosphonoa-cetic acid. These findings confirmed that FOM absorption from rabbit and human small intestines is associated with the phosphate transport system. These transport phenomena of FOM are in close agreement with those obtained previously in rat BBMV studies. Judging from the results obtained for three mammalian species, rat, rabbit and human, it was concluded that carrier-mediated transport via the phosphate transport system is a very important pathway of intestinal absorption of FOM.

Original languageEnglish
Pages (from-to)481-489
Number of pages9
Journaljournal of pharmacobio-dynamics
Issue number9
Publication statusPublished - 1992
Externally publishedYes


  • antibiotic
  • carrier-mediated transport
  • fosfomycin
  • human
  • intestinal brush-border membrane vesicle
  • intestinal uptake
  • rabbit
  • sodium-cotransport
  • species difference

ASJC Scopus subject areas

  • Pharmacology


Dive into the research topics of 'Mechanisms of Intestinal Absorption of the Antibiotic, Fosfomycin, in Brush-Border Membrane Vesicles in Rabbits and Humans'. Together they form a unique fingerprint.

Cite this