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Jørgen Frøkiær

Functional requirement of aquaporin-5 in plasma membranes of sweat glands

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  • Department of Molecular Biology
  • Department of Human Genetics
  • Biomedical Radio Isotope Techniques
  • Department of Anatomy
The distribution and function of aquaporins (AQPs) have not previously been defined in sweat glands. In this study, AQP1, AQP3, and AQP5 mRNA were demonstrated in rat paw by reverse transcription (RT)-PCR, but AQP2 and AQP4 were not. AQP1, AQP3, and AQP5 protein were confirmed in these tissues by immunoblotting. AQP1 was identified in capillary endothelial cells by immunohistochemical labeling, but not in sweat glands or epidermis. Abundant AQP3 expression was seen in basal levels of epidermis, but not in sweat glands. AQP2 and AQP4 were not observed in either skin or sweat glands. Immunohistochemical labeling revealed abundant AQP5 in secretory parts of rat and mouse sweat glands, where immunoelectron microscopy demonstrated abundant AQP5 labeling in the apical plasma membrane. AQP5 immunolabeling of human sweat glands yielded a similar pattern. To establish the role of AQP5 in sweat secretion, we tested the response of adult mice to s.c. injection of pilocarpine, as visualized by reaction of secreted amylase with iodine/starch. The number of active sweat glands was dramatically reduced in AQP5-null (-/-) mice compared with heterozygous (+/-) and wild-type (+/+) mice. We conclude that the presence of AQP5 in plasma membranes of sweat glands is essential for secretion, providing potential insight into mechanisms underlying mammalian thermoregulation, tactile sensitivity, and the pathophysiology of hyperhidrosis.
Original languageEnglish
JournalProceedings of the National Academy of Sciences of the United States of America
Volume99
Issue1
Pages (from-to)511-6
Number of pages6
ISSN0027-8424
DOIs
Publication statusPublished - 8 Jan 2002

    Research areas

  • Animals, Aquaporin 2, Aquaporin 3, Aquaporin 4, Aquaporin 5, Aquaporin 6, Aquaporins, Cell Membrane, Heterozygote, Immunoblotting, Immunohistochemistry, Kidney, Lung, Membrane Proteins, Mice, Mice, Transgenic, Microscopy, Immunoelectron, Muscarinic Agonists, Pilocarpine, RNA, Messenger, Rats, Rats, Wistar, Reverse Transcriptase Polymerase Chain Reaction, Skin, Subcellular Fractions, Sweat Glands, Water

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