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Paracellular intestinal absorption increases in mice exposed to cold
Author(s) -
Karasov William Henry,
Price Edwin R.,
Ruff Lisa,
Guerra Alberto
Publication year - 2012
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.26.1_supplement.885.18
Subject(s) - paracellular transport , tight junction , absorption (acoustics) , small intestine , chemistry , andrology , biology , biophysics , endocrinology , medicine , biochemistry , materials science , permeability (electromagnetism) , membrane , composite material
Recent studies of birds and bats demonstrate high passive (paracellular) absorption of nutrients. We hypothesized that a species with low paracellular absorption (mice) could increase absorption in response to increased energy demand. We predicted that mice exposed to cold would increase intestinal size to meet the increased energy demand, but in the short term these mice would increase paracellular absorption as well. We transferred mice from 21 to 5 °C and assessed absorption of radiolabeled L‐arabinose, a paracellular absorption probe, at 3 timepoints: prior to cold exposure; after 1 day of cold exposure; and after 2 weeks in the cold. We also assessed control mice kept at 21 °C. Mean gut size increased over the 2 week cold exposure, and this was accompanied by an increase in food consumption. Absorption of an L‐arabinose dose increased from 15.8% (prior to exposure) to 19.4% (P=0.006) after 1 day in the cold, and 21.5% (P<0.001) after 2 weeks exposure. We also assessed expression (qPCR) of tight junction proteins ZO‐1, Cldn2, Cldn4, and Cldn15, relative to housekeeping gene Eef1a1 in the medial intestine. Cldn2 was differentially expressed among treatment groups (P=0.02); however, there were no treatment‐induced differences in the expression of the other tight junction proteins. Our results suggest that mice may adjust tight junction “leakiness” to meet short‐term need for increased absorptive capacity.