Seasonal and diurnal rhythms of thyroidal status in the rainbow trout, Salmo gairdneri Richardson

Authors:
Publisher website
Google Scholar
Abstract
The concentrations of thyroxine (T4) and triiodothyronine (T3) in the blood plasma of rainbow trout (Salmo gairdneri Richardson) at intervals throughout the year have been measured by a chemically specific gas‐liquid chromatographic (GLC) method. Mean hormone levels showed a seasonal variation, maximal levels of both hormones occurring in winter and minimal concentrations in mid summer. An apparent secondary maximum in mean T4 and T3 concentrations was observed in spring. (T4)/(T3) ratios have been found to be highest in winter and lowest in summer. A radioimmunoassay procedure, validated by GLC analyses, revealed the presence of a diurnal rhythm in serum T4 levels of trout sampled in September and in April.

This publication has 22 references indexed in Scilit: