Relationship between small-intestinal transit rate and intestinal absorption of (14)C-labelled mannitol and (51)Cr-labelled ethylenediaminetetraacetic acid in healthy subjects.
BACKGROUND
Although the small-intestinal transit rate is generally considered to influence the urinary excretion of markers of intestinal permeability, no study has until now formally addressed the importance of this influence in humans.


METHODS
Ten healthy subjects ingested a test solution containing (99m)Tc-labelled diethylenetriaminepentaacetic acid ((99)mTc-DTPA), (14)C-labelled mannitol ((14)C-mannitol), and (51)Cr-labelled ethylenediaminetetraacetic acid ((51)Cr-EDTA). After ingestion, the small-intestinal transit rate of (99)mTc-DTPA was measured with the gamma camera technique. Urine was collected for time periods of 0-2 h, 2-4 h, and 4-6 h to measure the excretion of absorbed (14)C-mannitol and (51)Cr-EDTA. Moreover, the distribution volume and plasma clearance of (14)C-mannitol and (51)Cr-EDTA were determined in each subject.


RESULTS
A positive correlation was found between mean small-intestinal transit time and 0- to 6-h urinary excretion of (14)C-mannitol. The study did not show any correlation between small-intestinal transit rate and 0- to 6-h urinary excretion of (51)Cr-EDTA. Urinary excretion of neither (14)C-mannitol nor (51)Cr-EDTA was affected by distribution volume or urine volume. A positive correlation was observed between plasma clearance and 0- to 6-h urinary excretion of (14)C-mannitol, whereas plasma clearance did not influence the urinary excretion of (51)Cr-EDTA.


CONCLUSIONS
Small-intestinal transit rate seems to have a significant effect on 0- to 6-h urinary excretion of (14)C-mannitol, whereas small intestinal transit rate does not influence the timed urinary excretion of (51)Cr-EDTA.
Madsen
J L
JL
Dept. of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen, and Glostrup Hospital, Glostrup, Denmark.
Scharff
O
O
Rabol
A
A
Krogsgaard
O W
OW
D000328:Adult; D002250:Carbon Radioisotopes; D002860:Chromium Radioisotopes; D004492:Edetic Acid / Q000493:pharmacokinetics*; D015902:Gamma Cameras; D005772:Gastrointestinal Transit; D006801:Humans; D007408:Intestinal Absorption; D007421:Intestine, Small / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D008353:Mannitol / Q000493:pharmacokinetics*; D010539:Permeability; D011877:Radionuclide Imaging; D012016:Reference Values; D016284:Technetium Tc 99m Pentetate
D002250:Carbon Radioisotopes; D002860:Chromium Radioisotopes; D008353:Mannitol; D004492:Edetic Acid; D016284:Technetium Tc 99m Pentetate