Intestinal absorption, organ distribution, and urinary excretion of the rare sugar D-psicose.
BACKGROUND
The purpose of this study was to evaluate intestinal absorption, organ distribution, and urinary elimination of the rare sugar D-psicose, a 3-carbon stereoisomer of D-fructose that is currently being investigated and which has been found to be strongly effective against hyperglycemia and hyperlipidemia.


METHODS
This study was performed using radioactive D-psicose, which was synthesized enzymatically from radioactive D-allose. Concentrations in whole blood, urine, and organs were measured at different time points until 2 hours after both oral and intravenous administrations and 7 days after a single oral administration (100 mg/kg body weight) to Wistar rats. Autoradiography was also performed by injecting 100 mg/kg body weight of (14)C-labeled D-psicose or glucose intravenously to C3H mice.


RESULTS
Following oral administration, D-psicose easily moved to blood. The maximum blood concentration (48.5±15.6 μg/g) was observed at 1 hour. Excretion to urine was 20% within 1 hour and 33% within 2 hours. Accumulation to organs was detected only in the liver. Following intravenous administration, blood concentration was decreased with the half-life=57 minutes, and the excretion to urine was up to almost 50% within 1 hour. Similarly to the results obtained with oral administration, accumulation to organs was detected only in the liver. Seven days after the single-dose oral administration, the remaining amounts in the whole body were less than 1%. Autoradiography of mice showed results similar to those in rats. High signals of (14)C-labeled D-psicose were observed in liver, kidney, and bladder. Interestingly, no accumulation of D-psicose was observed in the brain.


CONCLUSIONS
D-psicose was absorbed well after oral administration and eliminated rapidly after both oral and intravenous administrations, with short duration of action. The study provides valuable pharmacokinetic data for further drug development of D-psicose. Because the findings were mainly based on animal study, it is necessary to implement human trials to study the metabolism pathway, which would give an important guide for human intake and food application of D-psicose.
Department of Pharmaco-Bio-Informatics, Faculty of Medicine, Kagawa University, Miki, Kagawa, Japan.
Ikuko
I
Tsukamoto
Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan ; Matsutani Chemical Industry Co, Ltd, Itami, Japan.
Akram
A
Hossain
Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Fuminori
F
Yamaguchi
Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Yuko
Y
Hirata
Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Youyi
Y
Dong
Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Kazuyo
K
Kamitori
Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Li
L
Sui
Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Machiko
M
Nonaka
Department of Inflammation Pathology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Masaki
M
Ueno
Division of Radioisotope Research, Life Science Research Center, Kagawa University, Kagawa, Japan.
Kazuyuki
K
Nishimoto
Division of Radioisotope Research, Life Science Research Center, Kagawa University, Kagawa, Japan.
Hirofumi
H
Suda
Rare Sugar Research Center, Kagawa University, Kagawa, Japan.
Kenji
K
Morimoto
Rare Sugar Research Center, Kagawa University, Kagawa, Japan.
Tsuyoshi
T
Shimonishi
Department of Pharmacy, Okayama University Hospital, Okayama, Japan.
Madoka
M
Saito
The First Affiliated Hospital, China Medical University, Shenyang, People's Republic of China.
Tao
T
Song
Department of Pharmaco-Bio-Informatics, Faculty of Medicine, Kagawa University, Miki, Kagawa, Japan.
Ryoji
R
Konishi
Department of Cell Physiology, Faculty of Medicine, Kagawa University, Kagawa, Japan.
Masaaki
M
Tokuda
D061605:Administration, Intravenous; D000284:Administration, Oral; D000818:Animals; D005632:Fructose / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine*; D007408:Intestinal Absorption; D051379:Mice; D008809:Mice, Inbred C3H; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
C003243:psicose; D005632:Fructose
14C-labeled D-psicose; autoradiography; organ accumulation; pharmacokinetics