title: Comparison of nonabsorbable markers Poly R-478 and [14C]PEG-4,000 for use in developmental absorption studies.
abstract: To determine the utility of Poly R-478, a stable, polymeric dye (MW, 40,000), as a nonabsorbable marker for studies in the developing small intestine, it was validated by comparison to carbon 14-labeled polyethylene glycol, MW 4,000 [( 14C]PEG-4,000) in rats from 14 to 40 days of age. The recovery and quantification of Poly R-478 from biological samples is simple and rapid compared to other nonradioactive nonabsorbable markers. In 40-day-old rats simultaneously given Poly R-478 and [14C]PEG, total recoveries were similar, the percentages of the Poly R-478 dose and the [14C]PEG dose recovered per segment were identical, and taurocholate absorption rates calculated using each marker were comparable. Recovery of Poly R-478 from flushed intestinal segments, determined by a one-step extraction, was equivalent to that of [14C]PEG in 40-day-old rats (96.5 +/- 3.7% versus 102.7 +/- 10.1%; NS) but was superior to that of [14C]PEG in 21-day-old rats (98.0 +/- 6.2% versus 63.4 +/- 5.5%; p less than 0.001) and 14-day-old rats (97.8 +/- 6.7% versus 56.7 +/- 12.6%; p less than 0.001). Within each age group, the distribution of Poly R-478 within the intestine was similar to that of [14C]PEG. In addition, total taurocholate absorption in the presence of Poly R-478 was comparable to that in the presence of [14C]PEG. Complete recovery of Poly R-478 from a suspension of liver particles and from mixtures with two commercial infant formulas was demonstrated in vitro, suggesting that Poly R-478 may be used when foods are present in the intestine.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Division of Neonatology, Hospital of the University of Pennsylvania, Philadelphia.
authors.forename: G E
authors.initials: GE
authors.lastname: Stahl
authors.forename: J C
authors.initials: JC
authors.lastname: Fayer
authors.forename: S C
authors.initials: SC
authors.lastname: Ling
authors.forename: J B
authors.initials: JB
authors.lastname: Watkins
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000880:Anthraquinones; D002250:Carbon Radioisotopes; D004396:Coloring Agents; D005502:Food; D007408:Intestinal Absorption / Q000502:physiology*; D007422:Intestines / Q000254:growth & development*; D008297:Male; D011092:Polyethylene Glycols; D011108:Polymers; D051381:Rats; D011919:Rats, Inbred Strains; D012044:Regression Analysis; D013656:Taurocholic Acid / Q000378:metabolism
chemical_list: D000880:Anthraquinones; D002250:Carbon Radioisotopes; D004396:Coloring Agents; D011108:Polymers; D011092:Polyethylene Glycols; D013656:Taurocholic Acid; C017971:poly R-478