the observation that normal serum concentrations of t ( 4 ) d , ft ( 4 ) , t ( 3 ) d , and ft ( 3 ) may be associated with undetectable basal serum tsh concentrations and suppressed tsh response to trh was also found in four hypothyroid patients given increasing doses of l-thyroxine and sequential trh stimulation tests .
C0020676
hypothyroid
C0040165
thyroxine