Thyroid-gonad relationship in systemic lupus erythematosus

Thirty women with systemic lupus erythematosus (SLE) were examined to assess the thyroid-gonad relationship. Significant decreases in mean serum tri-iodo-thyronine and testosterone levels and increases in mean serum estradiol and luteinizing hormone levels were observed in SLE patients as compared to control subjects. The serum levels of thyroxine, thyrotropin, tri-iodo-thyronine uptake, free thyroxine index and prolactin were, however, not significantly different in both groups. The interpretation of these findings is unclear but SLE could be regarded as one of the nonthyroidal systemic illness since low serum tri-iodo-thyronine with normal thyrotropin levels were observed in our patients. Furthermore, high levels of estradiol and low levels of testosterone in our female patients may indicate involvement of sex steroids in the pathogenesis of SLE.