| Abstrakt: |
ABSTRACTMeasurements of serum triiodothyronine (T3), thyroxine (T4) and thyrotropin (TSH) concentrations were made in hypothyroid patients at 2-hr intervals for 48 hr before and during chronic therapy with single daily doses of 25 and 50 μg T3or 100 and 200 μg T4. No time-related changes were found in serum T3, T4or TSH levels during therapy with 100 or 200 μg T4daily. In patients treated with T3, prompt increases in serum T3levels occurred which reached a peak after 4 hr and then gradually returned to base line. Base line serum T3levels were, respectively, 101 ± 13 and 94 ± 9 ng/100 ml (sem) and the peak levels were 223 ± 17 and 235 ± 18 ng/100 ml on the 2 study days in patients receiving 25 μg T3daily. Base line serum T3levels were 109 ± 18 and 116 ± 13 ng/100 ml and peak values were 350 ± 30 and 375 ± 31 in the patients receiving 50 μg T3daily. Serum TSH levels were elevated (mean basal serum TSH 13.1 ± 3.9 and 14.2 ± 4.7 μU/ml) in the patients receiving 25 μg T3daily and also elevated (mean basal serum TSH 11.8 ± 5.4 and 11.8 ± 6.0 μU/ml) in the patients receiving 50 (μg T3daily. No changes in serum TSH were observed in the intervals between doses of T3in either group.These results indicate that once daily T4therapy is not associated with any acute changes in either serum T4, T3or TSH levels. While striking alterations in serum T3levels follow once daily T3therapy, these changes are not associated with any acute changes in serum TSH levels. |
