Absorbed dose from 14C xylose and 14C mannose

Area of Science:

• Pharmacokinetics and Radiation Dosimetry
• Metabolic Fate of Carbohydrates
• Radiopharmaceutical Research

Background:

• Understanding the metabolic fate and tissue distribution of radiolabeled compounds is crucial for assessing radiation exposure.
• Oral administration is a common route for introducing substances into the body, necessitating studies on absorption and excretion.
• Accurate dosimetry is essential for risk assessment in studies involving radioactive isotopes.

Purpose of the Study:

• To determine the tissue distribution and excretion patterns of 14C xylose and 14C mannose in rodents.
• To calculate the effective dose-equivalent for both radiolabeled carbohydrates following oral administration.
• To evaluate the implications of compound clearance on long-term radiation dose estimation.

Main Methods:

• Oral administration of 14C-labeled xylose and mannose to rats and mice.
• Tissue distribution analysis over a 1-week period post-administration.
• Excretion studies to track the elimination of radioactivity.
• Calculation of effective dose-equivalent (microSv/MBq) based on distribution and excretion data.

Main Results:

• Significant differences in tissue distribution and excretion were observed between 14C xylose and 14C mannose.
• The effective dose-equivalent was calculated as 15 microSv/MBq for xylose and 120 microSv/MBq for mannose.
• No clearance of mannose was detected within the 1-week study period, indicating prolonged retention.

Conclusions:

• Mannose exhibits a longer retention time and higher effective dose-equivalent compared to xylose.
• The lack of mannose clearance necessitates assumptions about lifetime exposure for accurate long-term dosimetry.
• These findings are important for radiation safety assessments in preclinical studies involving these compounds.