AMS studies of the long-term turnover of C-14-labelled fat in man

To estimate the biokinetics of C-14-labelled fatty acids and the associated radiation absorbed dose to man, long-term retention of C-14 from Oral inta ke of glycerol tri[1-C-14]oleate (triolein) has been studied using accelera tor mass spectrometry (AMS). As a complement to earlier reported data for t hree individuals, we present here results for one person from measurements up to 4.6 yr after administration, now also including C-14-levels in fat, m uscle and bone. In this subject, a total of 44% of the administered activit y was recovered in the exhaled air. Fasting increased the exhalation of C-1 4. The "excess" (CO2)-C-14 due to fasting had a half-life of about 400 d. A MS measurements on fat, muscle and bone biopsies taken from the same subjec t 4.5 yr after ingestion indicated that a small fraction of the administere d activity was still present in fat. Also, bone tissue had a higher C-14 sp ecific activity than the current environmental level. No significantly incr eased level was found in the muscle sample. (C) 2000 Elsevier Science B.V. All rights reserved.