Decreased ratio of serum T3:rT3 in patients with hyperthyroidism

In 14 hyperthyroid patient serum T4:rT3 ratio was significantly lower (399 +/- 20) than in the control subjects (572 +/- 20; p less than 0.001). A similar pattern was found for serum T3:rT3 ratio. In the hyperthyroid group the ratio was significantly lower (10.5 +/- 0.5) than in the control group (12.5 +/- 0.6; p less than 0.05). The data suggest that in hyperthyroidism the organism might shift conversion of T4 from biologically active T3 to poorly calorigenic rT3. It seems possible that the proportionately increased generation of rT3 than that of T3 may be a defence mechanism of the body, as it was found in systemic illnesses and starvation.     

Serum T4, T3 and reverse T3 during treatment with propranolol in hyperthyroidism, L-T4 treated myxedema and in normal man.

Serum concentrations of T4, T3 and reverse T3 were studied in two hyperthyroid groups (n = 13 and 11), in a group of normals (n = 9) and in a group of L-T4 substituted patients (n = 7) with severe pretreatment hypothyroidism. Serum T4 did not change except in one of the hyperthyroid groups change to in which a slight decrease was found. In all groups a significant fall in serum T3 and a significant rise in serum reverse T3 were found. An expected increase in serum TSH in the normal and in the L-T4 substituted groups could not be demonstrated.     

Serum free triiodothyronine to free thyroxine ratio enables early prediction of the outcome of antithyroid drug therapy in patients with Graves' hyperthyroidism.

This study scrutinizes the correlation between serum free triiodothyronine (FT3) to free thyroxine (FT4) ratios and the eventual outcome of antithyroid drug (ATD) therapy in patients with Graves' disease. Forty-four patients with Graves' thyrotoxicosis were treated with methylmercaptoimidazole (methimazole). During the follow-up, 16 patients relapsed in the short period of one to five months after cessation of the drug (relapse group), and 28 patients remained in remission when checked at 12 to 20 months after treatment (remission group). Serum FT3 to FT4 ratios [(pg/ml/ng/dl) x 10] were less than 55 throughout ATD therapy in 27 of the 28 remission patients whereas the ratios of the relapse group exceeded 55 from the early phase of methimazole treatment in 10 of 16 patients. In eight of these 10 patients the increased ratios were detected within three months of therapy (1 month, 3 patients; 2 months, 4 patients; 3 months, 1 patient). The ratios for the remaining two patients rose above 55 at the fifth and sixth months. There was no statistical difference between the remission and relapse groups in the FT3 to FT4 ratios either before nor at the completion of the treatment. However, a clear difference could be measured at a point during the therapy. Those in whom this difference was pronounced later underwent relapse.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum selenium level in patients with colorectal cancer

Serum selenium levels were determined by fluorometric procedure in 37 patients of both sexes suffering from colorectal cancer. The diagnosis was verified with histopathological examination during surgical treatment. The values found were 46.8±11.2 μg/L. The control group consisted of 230 healthy persons from the same environment as the group of patients. The values found were 64.2±11.5 μg/L. The results of this study are compared with the results of the other research groups analyzing the level of selenium in colorectal cancer.     

Thyrotoxicosis with low serum total T3 level in patients with destructive thyroiditis and non-thyroidal illness.

The serum total T3 level, evaluated in 687 patients with thyrotoxicosis diagnosed by an elevated serum free T4 level and suppressed serum TSH level, was found to be high in 98.1% and normal in 1.9% of 592 patients with Graves' hyperthyroidism, and high in 75.8%, normal in 21.1% and low in 3.2% of 95 patients with destructive thyroiditis. Non-thyroidal illness was found in about a third of the patients with thyrotoxicosis and a normal serum total T3 level. The serum total T3 level was low with elevated serum thyroglobulin and reverse T3 levels in three patients with severe non-thyroidal illness, in whom the thyroidal radioactive iodine uptake was suppressed and the thyrotoxicosis resolved spontaneously with a normalization of the serum total T3 level after recovery from the destructive thyroiditis and non-thyroidal illness. It is therefore concluded that thyrotoxicosis with a low serum total T3 level, partially due to associated non-thyroidal illness, is more frequently found in patients with destructive thyroiditis than in those with Graves' hyperthyroidism.     

Serum T4, T3 and reverse T3 in ethanol fed rats.

To investigate the influence of chronic ethanol consumption on circulating thyroid hormone levels, male and female rats were given 20% ethanol as the only drinking solution daily for 8 weeks. Blood ethanol levels ranged 30–45 mg/L. In male rats serum T₄ decreased from the initial mean ± SD value of 5.2±1.4 to3.0 ±0.7 μg/dl; T₃ decreased from initial value of 97±14 to 66±11 ng/dl and rT₃ decreased from initial value of 19±9 to 10±1 ng/dl after 8 weeks of ethanol ingestion. Under similar experimental conditions, female rats showed a significant decrease in serum T₄ and rT₃ levels; however, T₃ levels decreased slightly but not significantly as compared to initial values. The results indicate adverse effect of chronic ethanol intake on serum thyroid hormone levels in rats.