Circadian Variations of Thyroid Hormone Levels of Nonpregnant Uniparous Fat-tailed Iranian Ewes in Summer

Authors : Saeed NAZIFI, Mahdi SAEB, Mahdi HASANKHANI, Maryam ANSARI-LARI

Pages : 137-140

View : 7 | Download : 5

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Circadian variations in serum triiodothyronine insert ignore into journalissuearticles values(T3);, thyroxine insert ignore into journalissuearticles values(T4);, free triiodothyronine insert ignore into journalissuearticles values(fT3);, and free thyroxine insert ignore into journalissuearticles values(fT4); levels were investigated in Iranian ewes. For that purpose, blood samples were collected from the jugular veins of 15 adult clinically healthy Iranian nonpregnant uniparous ewes every 6 h insert ignore into journalissuearticles values(0600, 1200, 1800, and 0000); during 6 days in summer with a mean ambient temperature of 40 °C. Serum T3, T4, fT3, and fT4 were measured by radioimmunoassay. There were statistically significant differences in thyroid hormone concentrations insert ignore into journalissuearticles values(T3, T4, fT3, and fT4); at different hours of the day. The results revealed that serum T3, T4, fT3, and fT4 levels were highest at 1800 insert ignore into journalissuearticles values(P < 0.05);. Significant 24 h periodicity in the serum levels of T3, T4, fT4 and fT3 was observed in nonpregnant uniparous Iranian ewes. It is concluded that circadian rhythm was observed in serum thyroid hormones.
Keywords : Circadian rhythm, triiodothyronine, thyroxine, nonpregnant uniparous ewes