Applicability of thyroxine measurements and ultrasound imaging in evaluations of thyroid function in turtles

Open access

Abstract

Introduction: The thyroid and parathyroid glands play a major role in maintaining physiological homeostasis in all vertebrates. Reptiles have plasma concentrations of thyroid hormones far lower than mammals. Low levels of these hormones in reptiles impede thyroid hormone detection with assays designed for the higher levels of mammals. The aim of this study was to explore teaming this with ultrasound imaging of the thyroid to appraise glandular function. Material and Methods: Thyroid function of four pond sliders was evaluated based on the results of T4 analyses and ultrasound. Results: The concentrations of T4 varied considerably between the examined animals from <9 nmol/L to >167.3 nmol/L. Ultrasound examination revealed uniform echogenicity and a smooth outline of the thyroid gland in all animals. Conclusion: Monitoring of thyroid function based on T4 and electrolyte concentrations is helpful in assessing the health and living conditions of reptiles, which is important in veterinary practice but problematic. Ultrasound examinations are useful in diagnosing changes in gland structure, such as tumours and goitres, and a combination of both methods supports comprehensive assessments of the anatomy and function of the thyroid gland.

1. Balletto E., Cherchi M.A., Melodia F., Mensi P.: Temperature-dependent thyroid hormone biosynthesis in Testudo horsfieldi Gray. Gen Comp Endocrinol 1979, 39, 548–561.

2. Bassett J.H.D., Harvey C.B., Williams G.R.: Mechanisms of thyroid hormone receptor-specific nuclear and extra nuclear actions. Mol Cell Endocrinol 2003, 213, 1–11.

3. Boyer T.H., Steffers Z.J.: Reptilian thyroid anatomy, physiology, and disease. Proc Assoc Reptilian Amphibian Veterinarians 2011, pp. 18–35.

4. Carpenter J.W., Mashima T.Y., Rupiper D.J.: Exotic Animal Formulary, Saunders, Saint Louis, USA, 2005, p. 108.

5. Dayan C.M.: Interpretation of thyroid function tests. Lancet 2001, 357, 619–624.

6. Gál J., Csikó G., Pásztor I., Bölcskey-Molnár A., Albert M.: First description of papillary carcinoma in the thyroid gland of a red-eared slider (Trachemys scripta elegans). Acta Vet Hung 2010, 58, 69–73.

7. Greenacre C.B., Young D.W., Behrend E.N., Wilson G.H.: Validation of a novel high-sensitivity radioimmunoassay procedure for measurement of total thyroxine concentration in psittacine birds and snakes. Am J Vet Res 2001, 62, 1750–1754.

8. Hernandez-Divers S.J., Knott C.D., MacDonald J.: Diagnosis and surgical treatment of thyroid adenoma induced hyperthyroidism in a green iguana (Iguana iguana). J Zoo Wildl Med 2001, 32, 465–475.

10. Hugenberger J.L., Licht P.: Characterization of thyroid hormone 5′- monodeiodinase activity in the turtle (Trachemys scripta). Gen Comp Endocrinol 1999, 113, 343–359.

11. Hulbert A.J., Williams C.A.: Thyroid function in a lizard, a tortoise and a crocodile, compared with mammals. Comp Biochem Physiol A Comp Physiol 1988, 90, 41–48.

12. Jacobson E.R.: Overview of reptile biology, anatomy, and histology. In: Infectious Diseases and Pathology of Reptiles: Color Atlas and Text, edited by Jacobson E.R., CRC Press, Taylor & Francis Group, Boca Raton, USA, 2007, pp. 19–20.

13. Kohel K.A., MacKenzie D.S., Rostal D.C., Grumbles J.S., Lance V.A.: Seasonality in plasma thyroxine in the desert tortoise, Gopherus agassizii. Gen Comp Endocrinol 2001, 121, 214–222.

14. Licht P.: Thyroxine-binding protein represents the major vitamin D binding protein in the plasma of the turtle, Trachemys scripta. Gen Comp Endocrinol 1994, 93, 82–92.

15. Licht P., Denver R.J., Stamper D.L.: Relation of plasma thyroxine binding to thyroidal activity and determination of thyroxine binding proteins in a turtle, Pseudemys scripta. Gen Comp Endocrinol 1990, 80, 238–256.

16. McArthur S., Meyer J.: Endocrine system. In: S. McArthur, R. Wilkinson, J. Meyer (eds): Medicine and Surgery of Tortoises and Turtles. Wiley-Blackwell, 2004, 71–72.

17. O’Steen S., Janzen F.J.: Embryonic temperature affects metabolic compensation and thyroid hormones in hatchling snapping turtles. Physiol Biochem Zool 1999, 72, 520–533.

18. Rivera S., Lock B.: The reptilian thyroid and parathyroid glands. Vet Clin North Am Exot Anim Pract 2008, 11, 163–175.

19. Rostal D.C., McCoy E.D., Mushinsky H.R.: Biology and Conservation of North American Tortoises. Johns Hopkins University Press, Baltimore 2014, pp. 93–94.

20. Sarkar S., Sarkar N.K., Bhattacharyya S., Das P.: Melatonin action on thyroid activity in the soft-shelled turtle, Lissemys punctata punctata. Folia Biol (Krakow) 1997, 45, 109–112.

21. Stamper D.L., Denver R.J., Licht P.: Effects of thyroidal status on metabolism and growth of juvenile turtles, Pseudemys scripta elegans. Comp Physiol 1990, 96A, 67–73.

22. Wail P.A.: The diversity of the endocrine system. In: R.K. Murray, D.K. Granner, V.W. Rodwell (eds): Harper’s Illustrated biochemistry, McGraw-Hill Education, LANGE, New York City, USA, 2015, pp. 507–511.

23. Wilkinson R., Hernandez-Divers S., Lafortune M., Calvert I., Gumperberger M., McArthur S.: Diagnostic imaging techniques. In: S. McArthur, R. Wilkinson, J. Meyer (eds): Medicine and Surgery of Tortoises and Turtles, Wiley-Blackwell, Oxford, U.K., 2004, pp. 187–190.

Journal of Veterinary Research

formerly Bulletin of the Veterinary Institute in Pulawy

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