Premium
Paracellular solute absorption varies with body size in primates
Author(s) -
McWhorter Todd Jason,
Karasov William H
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1275
Subject(s) - paracellular transport , bioavailability , absorption (acoustics) , marmoset , intestinal permeability , in vivo , chemistry , callithrix , permeability (electromagnetism) , primate , biology , biophysics , biochemistry , pharmacology , ecology , immunology , genetics , materials science , composite material , membrane
Earlier studies suggested that reliance on absorption of nutrients by a passive, paracellular route increases with body size in mammals. We measured fractional absorption of nonmetabolizable, nonactively transported carbohydrates by total urine collection and by appearance in blood post oral administration in common marmosets ( Callithrix jacchus , mean body mass = 0.370 ± 0.006 kg) and rhesus macaques ( Macaca mulatta , 8.912 ± 1.181 kg). The fractional absorption of the test carbohydrates decreased with increasing probe molecular weight, consistent with sieving in the tight junction between cells. We found no trend for increasing reliance on paracellular absorption with increasing size in nonhuman primates, in fact the contrary: the bioavailability of the test carbohydrates, an in vivo measure of intestinal paracellular permeability, decreased with increasing body size (averaged across paracellular probes, fractional absorption was 5.5‐fold greater in marmosets). Our results are consistent with the low bioavailability of these nonmetabolizable carbohydrates in humans, suggesting a general pattern of decreasing paracellular intestinal permeability with increasing body size in primates. We also measured absorption of 3‐O‐methyl‐D‐glucose, an actively transported nonmetabolizable glucose analog, and found its absorption to be high and similar among marmosets and macaques. It is likely that primates absorb the majority of their water soluble nutrients by active transport, similar to other nonflying mammals. Low passive absorption may also reduce exposure to dietary water soluble toxins. Supported by NSF IBN‐0216709 to WHK and NIH P51 RR000167 to the Wisconsin National Primate Research Center.