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Updated: May 31, 2026

Culturing Primary Rat Inner Medullary Collecting Duct Cells
Published on: June 21, 2013
Dual functional characteristic of human aquaporin 10 for solute transport
Megumi Ishii1, Kinya Ohta, Takahiro Katano
1Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
Background/Aims:
Although aquaglyceroporins have been generally believed to operate in a channel mode, which is of nonsaturable nature, for glycerol as well as for water, we recently found that human aquaporin 9 (hAQP9) operates in a carrier-mediated mode, which is of saturable nature, for glycerol. Based on the finding, we assumed that such a characteristic might be shared by the other aquaglyceroporins and examined the functional characteristics of hAQP10, which is an intestine-specific aquaglyceroporin.
Methods:
Transport assays were conducted using Xenopus laevis oocytes expressing hAQP10 derived from the microinjected cRNA.
Results:
The transport of glycerol by hAQP10 was found to be highly saturable with a Michaelis constant of 10.4 μM and specifically inhibited by several glycerol analogs such as monoacetin. Furthermore, when glycerol was preloaded in hAQP10-expressing oocytes, its efflux was trans-stimulated by extracellular glycerol. These results indicate the involvement of a carrier-mediated mechanism in glycerol transport by hAQP10. Interestingly, a channel mechanism was also found to be involved in part in hAQP10-mediated glycerol transport.
Conclusion:
The present study unveiled the uniquely dual functional characteristic of hAQP10 as a carrier/channel for solute transport, providing a novel insight into its operation mechanism, which would help further elucidate its physiological role.
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