The influence of caloric deprivation and food composition on TSH, thyroid hormones and nuclear binding of T3 in mononuclear blood cells in obese women.

In vivo changes in thyroid-stimulating hormone (TSH), thyroxin (T4), triiodothyronine (T3) and nuclear binding of T3 (NBT3) in mononuclear blood cells were studied in obese women during seven days of caloric deprivation (maximum 1,100 kcal/d). In seven women given a high protein diet (80% protein, 7% carbohydrates, 7% fat) and in two women who fasted (group 1), total T3 (TT3) decreased from 1.66 +/- 0.43 nmol/L to 1.11 +/- 0.32 nmol/L (P less than .01), free T3 (FT3) decreased from 5.7 +/- 1.1 pmol/L to 4.3 +/- 1.6 pmol/L (P less than .01), and free T4 (FT4) increased from 17.8 +/- 2.3 pmol/L to 21.1 +/- 2.0 pmol/L (P less than .01). In five women given a carbohydrate diet (Dextrin-maltose 100%) (group 2), thyroid hormones were unchanged, TT3 was at start 1.66 +/- 0.24 nmol/L and after seven days 1.43 +/- 0.26 nmol/L (NS), FT3 changed from 6.4 +/- 1.8 pmol/L to 6.0 +/- 2.1 pmol/L (NS) and FT4 changed from 20.4 +/- 5.1 pmol/L to 20.6 +/- 3.1 pmol/L (NS). The caloric intake and the weight reduction was the same in the two groups. Basal TSH and TSH after thyrotropin-releasing hormone (TRH) (TSH+30min) declined in both groups. In group 1, basal TSH declined from 1.88 +/- 1.07 microU/mL (P less than .03), and TSH+30min declined from 12.44 +/- 7.49 microU/mL to 9.38 +/- 5.97 microU/mL (P less than .03). In group 2, basal TSH declined from 2.09 +/- 0.87 microU/mL to 1.66 +/- 0.92 microU/mL (P less than .03), and TSH+30min declined from 15.63 +/- 7.90 microU/mL to 11.93 +/- 7.20 microU/mL (NS).(ABSTRACT TRUNCATED AT 250 WORDS)