Plasma Thyroid Hormone Concentrations in Dogs Competing in a Long-Distance Sled Dog Race

David L. Panciera, Kenneth W. Hinchcliff, Jeanne Olson, Peter D. Constable

Research output: Contribution to journalArticlepeer-review


Plasma thyroxine (T4), 3,5,3′-triiodothyronine (T3), total protein, and albumin concentrations were measured in 15 dogs both before and after completion, and in an additional 16 dogs before and 24 dogs after completion, of a long-distance sled dog race. The plasma T4 concentration (mean ± SD) decreased significantly from 18.2 ± 5.4 nmol/L before to 14.3 ± 3.5 nmol/L after the race in dogs evaluated at both times and decreased significantly from 21.8 ± 10.5 nmol/L before to 15.8 ± 4.9 nmol/L after the race in dogs sampled only before or only after the race. The mean plasma T3 concentrations in dogs measured twice decreased significantly from 1.20 ± 0.48 nmol/L before to 0.74 ± 0.42 nmol/L after the race, as well as in dogs measured either before (1.28 ± 0.36 nmol/L) or after (0.69 ± 0.28 nmol/L) the race, respectively. Plasma total protein and albumin concentrations decreased significantly after completion of the race. No significant change was noted in 4 control dogs that did not compete in the race and were tested during a similar time period. The plasma concentrations of T4 and T3 were lower than the normal reference range established for this laboratory in 23 and 39%, respectively, of Alaskan sled dogs tested before the race. Plasma thyroid hormone concentrations frequently are below normal in conditioned Alaskan sled dogs and are further reduced after prolonged submaximal exercise.

Original languageEnglish (US)
Pages (from-to)593-596
Number of pages4
JournalJournal of veterinary internal medicine
Issue number4
StatePublished - Jul 2003


  • 3,5,3′-triiodothyronine
  • Sled dogs
  • Thyroxine

ASJC Scopus subject areas

  • veterinary(all)


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