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Expression and Functional Role of Aquaporins in Hepatocytes from a Freeze‐tolerant Amphibian
Author(s) -
Goldstein David L,
Wysong Robert,
Queiroga Monalisa M.,
Hughes Heather,
Leggett Kyle,
Frisbie James
Publication year - 2011
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.25.1_supplement.1047.1
Subject(s) - aquaporin , glycerol , permeability (electromagnetism) , hepatocyte , acclimatization , membrane permeability , aquaporin 3 , catfish , chemistry , biology , microbiology and biotechnology , in vitro , biochemistry , membrane , botany , fishery , fish <actinopterygii>
Cope's gray treefrog, Hyla chrysoscelis, tolerates freezing and, during cold acclimation, accumulates cryoprotective glycerol. The liver is a potential source of that glycerol, and cells of the liver also must tolerate stresses of freezing. We have identified two aquaporins expressed in gray treefrog liver, HC‐1 (a water channel) and HC‐3 (a glyceroporin conferring both water and glycerol permeability). Evaluation of isolated hepatocytes in vitro indicates that aquaporin expression/turnover, especially of HC‐3, is influenced by temperature (4C vs. 20C) and by culture conditions (e.g., presence of glycerol in the medium). Changes in total aquaporin expression include shifts in glycosylation pattern and in localization in the plasma membrane. Based on rates of cell swelling in hypotonic medium, hepatocytes from cold‐acclimated animals have enhanced water permeability (likely because of increased aquaporin expression). In hepatocytes from both warm‐ and cold‐acclimated animals, water permeability is much lower in cells tested at 4C than at 20C, and permeability is just partially inhibited by mercury. This research was supported by NSF Research Grant IOB‐0517301.