The use of Seralute® and Tetralute® for measurement of plasma triiodothyronine and thyroxine in salmonid fishes

Abstract

There was found to be a marked effect of sample volume on the measured and calculated (i.e. corrected for volume size) levels of thyroxine (T₄) and triiodothyronine (T₃) in trout plasma when using the Ames Tetralute^® and Seralute^® assay kits. Freezing and thawing caused a significant (p < 0.001) increase in plasma T₄ levels and a significant decrease (p < 0.01) in plasma T₃ levels. Further freezing and thawing and plasma storage at – 30 °C for 1 month had no significant effect on measured hormone levels.