No abstract

Blood cortisol, ACTH, thyroxine, triiodothyronine, reverse triiodothyronine, thyroid stimulating hormone (TSH) and vasopressin concentrations were determined in 9 runners (29\p=n-\56 years old) and one 80year old man taking part in a non-competitive Marathon in Athens, Greece on October 1976. After the run the mean concentrations of cortisol, ACTH and vasopressin showed a significant rise. The thyroid function variables and TSH did not differ from the control values. There was a significant correlation between the cortisol and ACTH levels after the race and also between their increments from the corresponding base values. A significant correlation was found between the physical fitness (as measured by indirect determination of Vo2max) and the post-race cortisol levels. One of the well trained runners with a fairly good running time had the highest post-race values for 6 of 7 hormones studied.

A case of a 33 year old man with type I of Reprints should be requested from Dr.

Free thyroxine (FT4) and free triiodothyronine (FT3) concentrations in serum were measured by direct equilibrium dialysis methods in patients receiving thyroxine replacement or suppression therapy. Four of 50 hypothyroid patients euthyroid on replacement therapy (mean thyroxine dose 120 \g=m\g/day) had supra\x=req-\ normal FT4 concentrations, whereas the FT3 concentrations were normal in all. Forty-one of 56 operated thyroid carcinoma patients on suppressive therapy (mean thyroxine dose 214 \g=m\g/day) had raised FT4 concentrations, whereas the FT3 concentration was elevated in only one patient. There was a large difference in mean FT4 values for hypothyroid and thyroid carcinoma patients (17.2 vs 29.5 pmol/l), whereas the difference in mean FT3 values was small (5.0 vs 6.1 pmol/l), suggesting a decreased peripheral conversion of T4 to T3 with increasing concentrations of FT4. Serum TSH concentrations, as determined by an immunoradiometric assay, varied from < 0.02 to 11.9 mU/l in treated hypothyroid patients; 21 patients (42%) had values outside the reference limits. As a single test, serum TSH is therefore not very useful for the assessment of adequate thyroxine dosage in patients with primary hypothyroidism. In thyroid carcinoma patients, the TSH concentrations were < 0.18 mU/l; 45 patients had values < 0.02 mU/l indicating sufficient suppression of TSH secretion in the majority of cases.On the basis of these results we recommend the combination of FT3 and TSH tests for monitoring thyroxine replacement and suppression therapy. FT4 appears less useful than FT3 for this purpose even if special reference values values were adopted for each patient group.Patients on therapy with thyroxine may have raised serum T4 and free T4 (FT4) concentrations but usually do not appear thyrotoxic unless serum T3 and free T3 (FT3) concentrations are also elevated (Salmon et al. 1982; Brajkovich et al. 1983;Pearce & Himsworth 1984; Mardell et al. 1985; Fraser et al. 1986). In these earlier investi¬ gations the free thyroid hormone levels in serum were studied using free hormone index or ana¬ logue-type methods. It is well-documented that in a number of situations such methods are inaccu¬ rate indicators of the true free hormone concen¬ trations (Ekins 1982; Liewendahl et al. 1984;Wilke 1986).The objective of the present study was there¬ fore to determine the usefulness of serum FT4 and FT3 concentrations, as measured by precise and accurate direct equilibrium dialysis methods, in monitoring thyroxine therapy in patients with primary hypothyroidism and patients operated for differentiated thyroid carcinoma. We also