THYROID-FUNCTION IN BULIMIA-NERVOSA

Basal thyroid-stimulating hormone (TSH) and thyroid hormone levels wer e evaluated in 18 women with bulimia nervosa during a period of active bingeing and vomiting and again after 7 weeks of abstinence from thes e behaviors and compared to measures in 27 control women. In 10 of the patients and 11 of the controls, the TSH nocturnal surge was calculat ed from hourly TSH measurements obtained in the afternoon from 1500 to 1900h and in the night from 2300 to 0400h. During the bingeing phase of the illness patients had lower total triiodothyronine (T3) values t han controls (p<.001). After 7 weeks without binge eating or purging, patients had lower T3, total thyroxine (T4), free triiodothyronine, fr ee thyroxine (FT4), reverse triiodothyronine and thyroid-binding globu lin (TBG) values compared to controls (p<.01) and significant reductio ns in T3, T4, FT4 and TBG compared to themselves in the active phase o f the illness (p<.02). The reduction in thyroid hormone levels was not due to a reduction in the nocturnal thyrotropin surge, since surge va lues did not differ between normals and patients at either phase of th e illness. Bulimics in the bingeing phase of the illness showed a posi tive correlation between caloric intake and TSH values (p<.01), sugges ting that food bingeing may stimulate thyroid activity. In sum, these results show a substantial reduction in thyroid hormone levels after 7 weeks of abstinence from bingeing and vomiting behaviors.