Mahdi SAEB, Saeed NAZİFİ, Mahdi HASANKHANİ, Maryam ANSARI-LARI

Circadian variations in thyroid hormone levels of nonpregnant uniparous fat-tailed Iranian ewes in summer

Circadian variations in serum triiodothyronine (T3), thyroxine (T4), free triiodothyronine (fT3), and free thyroxine (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 (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 (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 (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.

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1. Kaneko, J.J.: Clinical Biochemistry of Domestic Animals. 4th edn., Academic Press., New York. 1989; 630-648.
2. Assane, M., Sere, A.: Influence of the season and of gestation on the plasma concentration of thyroid hormones: triiodothyronine (T3) and thyroxine (T4) in Sahel Peulh ewes. Ann. Rech. Vet., 1990; 21: 285-289. (article in French with an abstract in English)
3. Salem, M.H., EI-Sherbiny, A.A., Khalil, M.H., Yousef, M.K.: Diurnal and seasonal rhythm in plasma cortisol, triiodothyronine and thyroxine as affected by the wool coat in Barki sheep. Indian J. Anim. Sci., 1991; 61: 946-951.
4. Ashutosh, M., Dhanda, O.P., Kundu, R.L.: Effect of climate on the seasonal endocrine profile of native and crossbred sheep under semi-arid conditions. Trop. Anim. Health Prod., 2001; 33: 241- 252.
5. Krebietke, P.: Diurnal rhythms of thyroid hormones in rooster chicks (Gallus domesticus). 1. Studies on the colloid epithelium protein, the radioiodine accumulation in the thyroid gland and the plasma radioiodine concentration. Endokrinologie, 1975; 65: 33- 41. (article in German with an abstract in English)
6. Krebietke, P.: Diurnal rhythms of thyroid hormones in rooster chicks (Gallus domesticus). 2. Studies on the protein-bound radioiodine and the “free” hormone portion. Endokrinologie, 1975; 65: 42-52. (article in German with an abstract in English)
7. Guagnano, M.T., Del Ponte, A., Menduni, P., Nuzzo, A., Palummeri, E., Angelucci, E., Vitacolonna, E., Sensi, S.: Time structure of endocrine secretion. II. Circannual variations in the free fractions of tri- and tetraiodothyronine, cortisol, human growth hormone and plasma insulin in healthy subjects. Boll. Soc. Ital. Biol. Sper., 1983; 59: 1243-1247. (article in Italian with an abstract in English)
8. Wong, C.C., Döhler, K.D., Atkinson, M.J., Geerlings, H., Hesch, R.D., von zur Mühlen, A.: Influence of age, strain and season on diurnal periodicity of thyroid stimulating hormone, thyroxine, triiodothyronine and parathyroid hormone in the serum of male laboratory rats. Acta. Endocrinol. (Copenh)., 1983; 102: 377- 385.
9. Komosa M., Flisi´nska-Bojanowska A., Gill J.: Development of diurnal rhythm in some metabolic parameters in foals. Comp. Biochem. Physiol. A., 1990; 95: 549-552.
10. Flisi´nska-Bojanowska, A., Komosa, M., Gill, J.: Influence of pregnancy on diurnal and seasonal changes in cortisol, T3 and T4 levels in the mare blood serum. Comp. Biochem. Physiol. A., 1991; 98: 23-30.
11. Souza, M.I.L., Bicudo, S.D., Uribe-Velásquez, L.F., Ramos, A.A.: Circadian and circannual rhythms of T3 and T4 secretions in Polwarth-Ideal rams. Small Ruminant Res., 2002; 46: 1-5.
12. Oki, C., Atkinson, S.: Diurnal patterns of cortisol and thyroid hormones in the Harbor seal (Phoca vitulina) during summer and winter seasons. Gen. Comp. Endocrinol., 2004; 136: 289-297.
13. Nazifi, S., Saeb, M., Karimi, T., Ghanbari, S.: Diurnal variation of serum biochemical parameters in the Iranian fat-tailed sheep. Comp. Clin. Pathol., 2005; 14: 1-4.
14. Norusis, M.Y.: SPSS for Windows Base System User’s Guide Release 6.0. 1st edn., SPSS Inc., Michigan. 1993; 281-290.
15. Weeke, J., Gundersen, H.J.: Circadian and 30 minutes variations in serum TSH and thyroid hormones in normal subjects. Acta. Endocrinol. (Copenh)., 1978; 89: 659-672.
16. Abdel-Samee, A.M.: Heat adaptability of growing Bedouin goats in Egypt. Tropenlandwirt, 1996; 97: 137-147.
17. Nazifi, S., Saeb, M., Rowghani, E., Kaveh, K.: The influences of thermal stress on serum biochemical parameters of Iranian fattailed sheep and their correlation with triiodothyronine (T3), thyroxine (T4) and cortisol concentrations. Comp. Clin. Pathol., 2003; 12: 135-139.
18. Khanna, D., Agarwal, S.P., Gupta, M.L., Rai, A.K., Khanna, N.D.: Effect of water deprivation during summer and winter on thyroid hormones concentration in the Indian camel. Indian J. Anim. Sci., 1996; 66: 253-255.
19. Freake, H.C., Schwartz, H.L., Oppenheimer, J.H.: The regulation of lipogenesis by thyroid hormones and its contribution to thermogenesis. Endocrinology, 1989; 125: 2868-2874.
20. Sturgess, I., Thomas, S.H., Pennell, D.J., Mitchell, D., Croft, D.N.: Diurnal variation in TSH and free thyroid hormones in patients on thyroxine replacement. Acta Endocrinol. (Copenh)., 1989; 121: 674-676.