Endocrine Abstracts

We examined the effects of L-thyroxin on level of prolactin (PRL), CRP (C-reactive protein) and insulin in premenopausal women with subclinical hypothyreoidism (SH).

The study included 21 women ages 41.3±3.5 years with SH (TSH>mIU/ml with normal level of T3 and T4).

Laboratory evaluation included basal hormone (serum free T3, free T4, TSH, PRL, insulin, cortisol, ACTH, GH, FSH, LH, E2, thyroid antibodies and TGL), level of CRP and level of lipids.

Radiological investigation included thyroid echosonography and scintigraphy. Percentile, average and correlation analysis have been utilized in statistical analysis. Eleven patients had hyperprolactinaemia, 14 patients had fasting hyperinsulinaemia and 8 patients had amenorrhoea. All patients were treated with low dose of L-thyroxin (25–50 ug). After the six months treatment, women had normal or limited.

TSH, level of PRL significantly decreased (839±145 vs 421±89 uIU/ml), level of CRP (5.9±1.4 vs 2.7±0.9 mg/l) and fasting insulin (231±85 vs 153±42 pmol/l) decreased as well. Six of eight women with amenorrhoea had regular menstrual cycles. The correlation between TSH and amenorrhoea was positive and significant (r=0.43). The correlation between TSH and PRL, TSH and CRP, TSH and insulin was positive, as well.

The normalization of TSH on one side resulted in decrease of level of PRL, FSH and LH and on the other side in increase of E2. Higher CRP associated with fasting hyperinsulinaemia before insulin resistance has been evidenced in most patients with SH. These data support an important role of treatment of SH in premenopausal women. In sum, the screening of TSH in all women older than 35 years is necessary.