Reverse Triiodothyronine in Liver Disease

A simple radioimmunoassay for serum reverse triiodothyronine on small reusable Sephadex G 25 fine columns has been developed. The assay was unaffected by serum volumes of up to 100 \g=m\l . The recovery of reverse T3 added to serum was in the mean 98.3 \m=+-\sem 3.2 % and the coefficient of variation within and between assay determinations 5.4 % and 7.5 %, respectively. The detection limit was 2.2 pg reverse T3/column. Serum reverse T3 in 58 euthyroid controls was in mean 48 \ m=+-\ sd 9 ng/100 ml, and was positively correlated to age (P < 0.001). No overlap was found between the control group, and the hypo-and hyperthyroid group respectively. Three patients with T3-toxicosis had a normal serum rT3.

Section: Discussionsupporting

confidence: 80%

“…The mean normal values of serum rT3 in different laboratories vary from 16 ng/100 ml(Ködding et al 1976) to 60 ng/100 ml(Burman et al 1976). This may be due to methodological difficulties such as interference from the binding proteins of rT3.…”

mentioning

confidence: 99%

Radioimmunoassay of 3,3′,5′-Triiodothyronine (Reverse T3) on Small Reusable Sephadex Columns

Faber

Friis

Kirkegaard

et al. 1978

“…In contrast, serum T3 and free T3 or free T3 index are decreased (Chopra et al 1974(Chopra et al , 1978Ködding et al 1976;Green et al 1977;Faber et al 1979;Sheridan et al 1978). Furthermore, reverse T3 has been reported to be increased (Ködding et al 1976;Chopra et al 1978;Faber et al 1979).…”

Section: Discussionmentioning

confidence: 99%

Increase in thyroxine-binding globulin (TBG) in lysinuric protein intolerance

Lamberg

Perheentupa

Rajantie

et al. 1981

The common occurrence of increased serum PBI concentration in patients with lysinuric protein intolerance (LPI) was elucidated by further studies. The reason was found to be an increase in the concentration of thyroid binding globulin (TBG), concomitantly with an increase in the binding capacity of TBG. The concentrations of serum thyroxine and triiodothyronine were elevated, whereas the free thyroxine index remained normal. The free triiodothyronine index was slightly increased. The binding capacity of thyroid hormone binding pre-albumin (TBPA) was significantly decreased.The concentrations of reverse triiodothyronine (3,3' ,5' \x=req-\ T3) and of 3,3'-diiodothyronine were normal. In all patients serum lactic acid dehydrogenase activities and ferritin concentrations were elevated. The reason for the almost constant increase in TBG remains obscure. It may be related to the primary disorder of LPI, a defect in diaminoacid transport.

“…This assump¬ tion finds support in previous animal studies in which PTU was able to in¬ hibit the conversion of T4 to T3 (Oppenheimer et al 1972;Bemal 8c Escobar del Rey 1974). PTU might influence the same metabolic systems effective in the shift in T4 conversion towards the metabolically inactive rT3 in systemic illness and following surgery (Burr et al 1976;Chopra 1976;Ködding et al 1976). In vitro studies by Höffken et al (1976) on rat liver homogenates, how¬ ever, have shown that the generation of both T3 and rT3 was suppressed by PTU.…”

Section: Discussionmentioning

confidence: 99%

“…The concentration of metabolically in¬ active rT3 has been found to be elevated in situations with low serum T3 such as systemic illness, starvation and during surgery (Burr et al 1975;Chopra et al 1975;Burger et al 1976;Chopra 1976;Ködding et al 1976;Nicod et al 1976). Data on the effect of antithyroid drugs on the conversion of T4 to T3 and rT3 seems sparse.…”

mentioning

confidence: 99%

Extrathyroidal Effects of Propylthiouracil and Carbimazole on Serum T4, T3, Reverse T3 and TRH-Induced TSH-Release in Man

Siersbæk-Nielsen

Kirkegaard

Rogowski

et al. 1978

A possible extrathyroidal effect of propylthiouracil (PTU) and carbimazole on serum levels of thyroxine (T4), triiodothyronine (T3), 3,3\m=' \,5\m=' \-triiodothyronine (reverse T3) and on thyrotrophin-releasing hormone (TRH) induced thyrotrophin (TSH) release was estimated in 19 patients with severe hypothyroidism treated with T4. During PTU medication a significant decrease in serum T3 from 90 \m=+-\16 (sd) to 79 \ m=+-\23 ng/100 ml (P < 0.01) and a reciprocal increase in serum reverse T3 from 51 \m=+-\14 (sd) to 58 \m=+-\20 ng/100 ml (P < 0.025) were found. No significant changes in serum T4, basal serum TSH or response to TRH could be demonstrated. Carbimazole did not change any of the parameters studied. Several animal and in vitro studies have provided evidence that propylthiouracil (PTU) in addition to an intrathyroidal effect inhibits the monodeiodination of thyroxine (T4) and also that of triiodothyronine (T3) (Braverman 8c Ingbar 1962; Morreóle de Escobar 8c Escobar del Rey 1962; Oppenheimer et al. 1972; Frumess 8c Larsen 1975). PTU has also been shown to increase the T4/T3 ratio in the pituitary gland and to increase the thyrotrophin (TSH) response to thyrotrophin-releasing hormone (TRH) in thyroidectomized rats (Escobar del Rey et al. 1972).Recent studies in man have demonstrated that PTU in contrast to methimazole can reduce the serum levels of T3 in T4-treated hypothyroid patients (Saberi et al. 1975). In a similar study in athyreotic man an increase in TRH-induced