Jl. Murphy et al., METABOLIC HANDLING OF C-13 LABELED TRIPALMITIN IN HEALTHY CONTROLS AND PATIENTS WITH CYSTIC-FIBROSIS, Archives of Disease in Childhood, 79(1), 1998, pp. 44-47
Aim-To examine the gastrointestinal handling and metabolic disposal of
emulsified [1-C-13]palmitic acid esterified into a triglyceride in ni
ne healthy children and seven patients with cystic fibrosis on enzyme
replacement treatment. Methods-After an overnight fast, each child was
given 10 mg/kg body weight [1,1,1-C-13]tripalmitin with a standardise
d test meal of low natural C-13 abundance. The total enrichment of C-
13 was measured using isotope ratio mass spectrometry in stool collect
ed for a period of up to five days and in breath samples collected ove
r a 24 hour period. Results-The mean proportion of administered( 13)C
label excreted in stool was 6% (range, 1-12.7%) in healthy children an
d 24.6% (range, 0-64%) in patients with cystic fibrosis. Healthy child
ren excreted 31.3% of the administered label on their breath (range, 1
4.2-42.9%). Correcting the excretion of administered C-13 label on the
breath for differences in digestion and absorption in patients with c
ystic fibrosis increased the difference between individuals from 0-31.
3% of administered dose (mean, 17.9%) to 0-49.1% of absorbed dose (mea
n, 23.2%) and was poorly related to the amount of C-13 label in stool.
Conclusion-Measurements of breath (CO2)-C-13 do not consistently refl
ect the gastrointestinal handling of emulsified C-13 labelled tripalmi
tin because of differences in digestion and absorption in cystic fibro
sis. Further studies need to examine whether ''breath tests'' alone ca
n predict with confidence the gastrointestinal handling of other C-13
labelled triglycerides and fatty acids.