Title

Diel Variations in Circulating Levels of Triiodothyronine and Thyroxine in Goldfish, Carassius auratus

Document Type

Article

Publication Date

3-1979

Publication Title

Canadian Journal of Zoology

ISSN

0008-4301

Volume

57

Issue/No.

3

First Page

665

Last Page

669

Abstract

Goldfish maintained on a 12 h light: 12 h dark photoperiod (light onset 0800 hours) and sampled at one of six different times of day had significant differences in both serum triiodothyronine (T3) and thyroxine (T4) levels depending on the time of day of sampling. Hormone titers were determined by commercial radioimmunoassay kits. Maximum levels for T3 and T4 occurred at 1600 hours; minimum levels occurred during the 4 h preceding the onset of light (0400- and 0800-hour samples). There was no apparent effect of sampling stress (< 15 min) on titers of T3 and T4.

Comments

©1979 National Research Council of Canada/Conseil national de recherches du Canada

DOI

10.1139/z79-079

Peer Reviewed

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