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The effects of thyroid hormones on various organs and metabolic systems have been the focus of intensive research. In this study we investigated the mechanisms of the changes in some parameters of bone and mineral metabolism before and during treatment of hyper- and hypothyroidism. Our study groups were as follows; 1) Untreated hyperthyroid patients (n= 38), 2) Hyperthyroid patients treated for three months (n=21), 3) Untreated hypothyroid patients (n=27), 4) Hypothyroid patients treated for three months (n= 20), and 5) Euthyroid control subjects (age, weight, sex and menopausal status matched) (n = 47). As expected, the mean serum calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), and urinary Ca/creatinine and deoxypyridinoline (D-Pyr)/creatinine levels were higher in group-1 than in the control group. Serum PTH level was lower in group-1 than in group-5. However, after treatment for three months (group-2) we found that the serum and urinary levels of these parameters (except ALP) were not different than in the control group. Group-3 and group-4 did not show any differences in these parameters compared with group-5. Covariance analysis showed that urinary D-Pyr excretion had a positive, independent relationship to the serum free T3 level and age (P < 0.001 and P = 0.02, respectively). These results suggest that both bone formation and resorption markers increase in hyperthyroid patients, and with the treatment, particularly, in the period of first three months the bone resorption markers decrease rapidly. If the treatment is maintained the decrease slows, becoming more gradual. However, bone formation markers like ALP remain high in hyperthyroid patients during the treatment. In the light of this data, it is possible to conclude that osteoblastic activity lasts longer in hyperthyroidism. On the other hand, we demonstrated that these bone formation and resorption markers do not seem to be different in hypothyroid patients, even during the treatment, compared to the euthyroid controls.

We examined the relationships existing between serum cytokine levels and bone mineral density (BMD) in women of premenopausal age affected by Graves' disease with subclinical hyperthyroidism. The study population consisted of 21 women with untreated hyperthyroid Graves' disease (group H) (age, 36 +/- 2 years), eight women with untreated subclinical hyperthyroid status (group SH) (age, 33 +/- 5 years) and 10 healthy women (group N) (age, 35 +/- 3 years). The following measurements were made in all patients: free T4 (fT4), free T3 (fT3), thyroid stimulating hormone (TSH), TSH receptor antibody (TRab), anti-thyroid peroxidase antibody (anti-TPO), anti-thyroglobulin antibody (anti-Tg), interleukin-2 receptor (IL-2r), interleukin-4 (IL-4), interleukin-8 (IL-8) and interleukin-13 (IL-13). IL-2r and IL-8 levels significantly increased in group H compared with group SH (p0.01 and p = 0.05, respectively) and group N (p0.001 and p = 0.02, respectively). IL-4 and IL-13 levels tended to be lower in groups H and SH compared with group N, although this difference did not reach statistical significance. Bone mineral density was significantly reduced in only two areas of the femur in group H compared with group N. There was no difference in BMD between groups SH and N. There was no correlation between thyroid hormones, serum cytokine levels and BMD in either group. In conclusion, these results suggest that there were no relationships existing between the serum level of these cytokines and BMD in women of premenopausal age affected by Graves' disease with subclinical hyperthyroidism.