Measurement of urinary total ¹³C and ¹³C urea by isotope ratio mass spectrometry after administration of lactose [¹³C]-Ureide

Morrison, D. , Dodson, B. and Preston, T. (1999) Measurement of urinary total ¹³C and ¹³C urea by isotope ratio mass spectrometry after administration of lactose [¹³C]-Ureide. Rapid Communications in Mass Spectrometry, 13(13), pp. 1252-1256. (doi: 10.1002/(SICI)1097-0231(19990715)13:13<1252::AID-RCM565>3.0.CO;2-J)

Abstract

A method of measuring total ¹³C excreted in urine after oral administration of lactose [¹³C]-ureide was developed using isotope ratio mass spectrometry. Furthermore, a method to measure ¹³C urea excreted in the urine was developed. Each urine sample collected over a 24 hour period, after administration of the tracer dose, was analysed for both total ¹³C and ¹³C urea. Combustion of the dried urine samples allowed measurement of the total ¹³C content. Treatment of urine samples with urease (EC 3.5.1.5) and analysis by isotope ratio mass spectrometry of the CO₂ evolved allowed measurement of ¹³C urea in the urine sample. The total ¹³C and ¹³C urea contents of each urine sample, obtained throughout the protocol, were compared to total ¹³C and ¹³C urea contents of a urine sample taken before the test. This allowed calculation of the fraction of tracer incorporated into urea and the fraction of tracer excreted in total. Analyses showed that approximately 15% of the dose administered, in terms of ¹³C, was recovered in the urine over the sampling period. Further analysis for urinary ¹³C urea showed that less than 1% of the label was incorporated into urea excreted over the sampling period.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Preston, Professor Tom and Morrison, Professor Douglas
• Authors: Morrison, D., Dodson, B., and Preston, T.
• Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Rapid Communications in Mass Spectrometry
• ISSN: 0951-4198
• Published Online: 15 July 1999