Study of the function of the hypothalamus-pituitary-thyroid system in rheumatoid arthritis (RA) MATERIALS AND METHODS: Three hundred and fifty patients with RA of different forms, stages, and intensity were examined. The blood and synovial fluid (SF) levels of thyroid-stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3) were measured by immunoradiometric assay.
Patients with RA were found to have higher T4 levels (in articular rheumatism, there was its negative correlation with the intensity of the process and in the presence of systemic manifestations of RA, there was a positive correlation). Blood T5 levels with higher RA intensity tended to increase in patients untreated with glucocorticosteroids. Blood TST concentrations showed an upward tendency which correlated with the intensity and stage of RA. Changes were also revealed in SF TST, T4, T3 levels.
The changes in the secretion of TSH, T4, T3 in patients with RA are caused by this pathological process and those in their SF levels affect the course of articular inflammation.