Whole-animal to molecular studies of solute transport in fishes

• Author / Creator

  Guffey, Samuel C

• I have examined solute transport in two fishes at the whole-animal, tissue, and molecular levels. In the Pacific hagfish, I measured the kinetics of phosphate absorption in isolated gut, skin, and gill preparations, and implicated an NaPi-II transporter based on RT-PCR results and the kinetics of phosphate uptake. In a second series of experiments, subjecting Pacific dogfish to reduced salinity revealed that plasma sodium and chloride homeostasis are maintained. Therefore these ions are not a limiting factor in reduced salinity; however, urea efflux significantly increased over the 48 hour exposure. Finally, I investigated the molecular physiology of sodium homeostasis by cloning Na+/H+ Exchanger [NHE] isoforms 2 and 3 from the dogfish gill and expressing them in NHE-deficient AP-1 cell lines. The sensitivity to inhibitors was found to be different from mammalian NHEs, revealing appropriate concentrations to use for elasmobranchs and other fishes, and allowing future mechanistic studies to be conducted.

• Subjects / Keywords

  • Homeostasis
  • Hagfish
  • Sodium
  • Salinity
  • NHE
  • Phosphate
  • Physiology
  • Dogfish

• Graduation date

  Fall 2013

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3HM52W41

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.