Aldosterone does not regulate amiloride-sensitive Na(+) transport in the colon of the Australian common brushtail possum, Trichosurus vulpecula

J Comp Physiol B. 2002 Aug;172(6):519-27. doi: 10.1007/s00360-002-0278-8. Epub 2002 Jul 9.

Abstract

Plasma aldosterone concentrations and the magnitude of amiloride-sensitive Na(+) transport in the proximal and distal colon of newly caught wild possums, and of possums maintained on either low or high Na(+) diets, were determined to evaluate their role in the regulation of salt content of faeces in common brushtail possums. Wild animals had a plasma aldosterone concentration of 439+/-115 pmol l(-1) and high levels of amiloride-sensitive Na(+) transport in both the proximal and distal colon. Animals maintained on a low Na(+) diet for 14 days excreted very little Na(+) in the urine and had an elevated aldosterone concentration (840+/-246 pmol l(-1)), but levels of amiloride-sensitive Na(+) transport in the proximal and distal colon were similar to those in wild animals. Conversely, while provision of a high Na(+) diet (7 days or 14 days) resulted in increased urinary Na(+) excretion and a fall in aldosterone (approximately 250 pmol l(-1)), there was no reduction in the amount of amiloride-sensitive Na(+) transport in either the proximal or distal colon. These data strongly indicate that aldosterone does not regulate amiloride-sensitive Na(+) transport in the colon of possums and that the colon is not involved in the regulation of salt content of the faeces in this species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldosterone / physiology*
  • Amiloride / blood*
  • Animal Feed
  • Animals
  • Animals, Wild / metabolism
  • Biological Transport / physiology
  • Colon / metabolism*
  • Colon / physiology
  • Diet, Sodium-Restricted
  • Electric Conductivity
  • Male
  • Natriuresis
  • Opossums / metabolism*
  • Potassium / urine
  • Sodium / metabolism*

Substances

  • Aldosterone
  • Amiloride
  • Sodium
  • Potassium