[Metabolism of 18F-FDG (2-fluoro-2-deoxy-D-glucose) in tumor cells].

Tumor cell components obtained at 5 min, 1 hr and 3 hr after 18F-FDG injections were analyzed by radio-TLC. Major metabolites were 18F-FDG-phosphate and 18F-FDM-phosphate. 18F-FDM and three unidentified compounds were found as minor metabolites.

[Uptake of FDG (2-fluoro-2-deoxy-D-glucose) as a tumor imaging agent into erythrocytes and accumulation of FDG in tumor cells].

Fluorine-18-2-fluoro-2-deoxy-D-glucose (18F-FDG) injectable was developed as a tumor imaging agent reflecting glucose metabolism. In membrane transportation studies, the uptake of 14C-FDG into erythrocytes decreased with an increase in glucose concentration, and Cytochalasin B, inhibitor of glucose transporter (GLUT), blocked the uptake about 75%. The results means FDG is transported into tumor cells mainly by GLUT as glucose analogues.

Kinetics of radioiodinated species in subcellular fractions from rat hearts following administration of iodine-123-labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (123I-BMIPP).

It is recognized that iodine-123-labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (123I-BMIPP) slowly washes out of the myocardium. The mechanism for the washout was investigated in normal rat hearts by analyses of the subcellular distribution and lipid classes based on the BMIPP metabolism. Rat hearts were excised at 1-120 min after intravenous injection of 123I-BMIPP.

[Pharmacokinetics of 123I-iomazenil, a benzodiazepine receptor seeker].

The biodistribution, metabolism and excretion of 123I-iomazenil have been studied in rats, rabbits and humans following i.v. administration.

Metabolism of iodine-123-BMIPP in perfused rat hearts.

Unlabelled: Increased clinical use of 123I-labeled 15-(p-iodophenyl)-3-(R,S)-methyl- pentadecanoic acid ([123I]BMIPP) revealed discordance between BMIPP uptake and that of perfusion agents, which was inexplicable due to the uncertainty of its myocardial metabolism. This study clarifies the metabolic fate of BMIPP and its relation to substrates in isolated rat hearts.

Methods: Rat hearts were perfused with 5 mmole/liter HEPES buffer containing various energy substrates and 1% bovine serum albumin.

[In vivo characteristics of IBZM in rat brains: an agent for quantitative SPECT imaging of D2 dopamine receptors--a basis for semiquantitative measurement of the receptor density using equilibrium analysis].

To establish a basis for semiquantitative SPECT measurements of the D2 dopamine receptor density using equilibrium analysis, we evaluated in vivo kinetic properties of 125I-IBZM in rat brains. We measured percent uptakes (% dose/g) of 125I-IBZM in the striatum, frontal cortex, and cerebellum. We made these regional measurements at 15, 30, 45, 60, 90, and 120 minutes after injection, respectively.

[In vivo characteristics of IBZM in rat brains: an agent for quantitative SPECT imaging of dopamine D2 receptors. Preparation of 125I-IBZM and its biodistribution and kinetic properties].

123I-(S)-(-)-3-iodo-2-hydroxy-6-methoxy-N-[(1-ethyl-2-pyrrolidinyl) methyl]-benzamide (IBZM) is a CNS dopamine D2 receptor imaging agent for SPECT and has already been used clinically in the United States, Canada and Europe. However, methods of quantitative SPECT measurement of the D2 receptor density have not been well established. We performed in vivo biodistribution studies of 125I-IBZM in rat brains as the first step toward establishment of a basis for quantitative SPECT imaging of D2 receptors in humans.

[Metabolite of 15-p-iodophenyl-3(R,S)-pentadecanoic acid (123I) in blood and urine].

We analyzed metabolites of 123I-BMIPP in blood and urine using rats, rabbits and human, while human samples were obtained from normal volunteers of Phase I clinical study. We estimated metabolic pathway of 123I-BMIPP as a myocardial metabolic imaging agent. Radioactivity accumulated in heart after administration gradually decreased and was mainly excreted to bladder via kidneys.