ISSN:
1095-8649
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Serum T4 and T3 in wild Atlantic cod Gadus morhua ranged from 1 to 12 ng ml−1 and from 2 to 27 ng ml−1 respectively over a 3-year period. In general, the concentrations increased from summer (T3) or early autumn (T4) to maxima in mid-winter and declined abruptly during spring. The T4/T3 monthly means were lowest in summer and highest in winter. The seasonal patterns of thyroid hormones were weakly correlated with changes in water temperature. However, both T4 and T3 co-varied simultaneously with photoperiod. In addition, T3 was correlated with the hepatosomatic index and condition factor during summer and autumn. It is suggested that the seasonal changes in the release of T4 from the thyroid were photoperioddriven, and that the course of T3 was regulated by the metabolic state of the fish during the somatic growth period.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1095-8649.2000.tb00261.x
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