Abstract

Aim Subclinical hypothyroidism is a clinical condition mostly observed in women, the prevalence of which increases by age. Sleepiness and appetite problems are observed in subclinical hypothyroidism. Orexins play a role in the physiological regulations like the stabilization of cardiovascular functions and the sleep-alert cycle. Similarities in the physiological regulation areas of orexins and the clinical fi ndings of hypothyroidism were infl uential in the planning of this research. Additionally, homosisteine, which is infl uential on the cardiovascular system and the plasma level of which changes by eating (as is the case with orexins), was also analyzed. Besides, the change in the lipid profi les of the patients was also observed. Material and Methods Nineteen pre-menopausal female patients (mean age=39.58±12.58, mean BMI= 26.7±4.9) included in this study. Following 12 hours fasting blood samples were taken from brachial vein. All patients were given 50µg/day L-T4 TSH levels were examined in every 4-6 weeks to adjust the L-T4 doses. When euthyroidism was ensured, a re-evaluation was made 4 months later. Results Pre-treatment plasma orexin A levels of 19 patients with pre-menopausal subclinical hypothyroidism increased signifi cantly following a treatment of l-tiroxin for 4 months (pre-treatment orexin level median=1.20 mg/dl (mean: 1.33±0.28) post-treatment median=1.82 mg/dl (mean: 1.70±0.42) p=0.007). A significant change in the level of plasma total homosisteine and lipid profile was not detected. Conclusion Advanced studies are needed to study the physiological effects of orexin levels in cases with subclinical hypothyroidism and the possible benefits in treatment.

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