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[en] In order to investigate the influence of experimental hiperthyroidism in the colinergic activity, rats were injected daily, during 1, 5, 19 or 20 days, with triiodothyronine (0 to 100 ug/kg, s.c.). The hiperthyroidism was evaluated by the decrease of the body weight and the increase of the body temperature and serum hormonal levels (T3). After the administration of the cholinergic agonists (pilocarpine and oxotremorine) or a anticholinesterase drug (eserine), the cholinergic behavioural and pharmacologic activity was evaluated recording the rectal temperature, locomotor activity, catalepsy, tremor and cromodacryorrhea. The results suggests that T3 pre-treatment may induce in rats changes in the functionality of the central cholinergic post-sinaptic receptors. However, the administration of this hormone does not seem to induce any alterations in the periferic cholinergic receptors, implicated in cromodacryorrhea effect. (author)

[en] Measurement of triiodothyronine(T³) concentration is usful for the diagnosic and treatment of thyroid gland diseases. Fundamental studies of measurement of T³ concentration by radioimmunoassay were performed and values determined by commercially available kit, Coat-A-Count, Diagnostic Products Corporation. The optimal utilization of the radioimmunoassay in measuring T³ condentration is dependent not only on high quality performance of the assay, but also on their appropriate application to the clinical situation. These are several aspects that must be considered in every individual case. These include factors such as accurate pippeting in reagent preparation in the assay and through decanting to remove all visible moisture after incubation steps and so forth. In attempt to assesses quality control of the radioimmunoassay of serum T³, serum pools with high, medium, low T³ concentrations were assayed for each of 5 samples. The results obtained with this study were as follows: 1. The coefficient of variation (C.V.) for the standard curve ranged between 0.2-3.5%. 2. It was necessary that both incubation time and temperature should correctly be maintained all the in the assay performance. 3.The precision with the T³ RIA procedure was good. 4. The measured values of serially diluted serum T³ concentration with 0ng/dl standard solution was proportional to the predicted values. However dilution curve of distilled water was not strait. 5. Calculated T³ values of patient serum in normal group was 107.8+-25.90 ng/dl in male patient and 127.29+-24.08 ng/dl in female patient. (Author)

[en] The experience acquired in the development of radioimmunoassay for T₄, T₃ and rT₃ in unextrated serum is described. Antisera were produced in rabbits using iodothyronines conjugated to bovine serum albumin: the antisera selected provided the development of sensitive and specific radioassay methods. Stable high activity T₃, T₄ and rT₃ tracers were prepared by iodination of 3,5 T₂, T₃ and 3,3' T₂ by the chloramine-T method, and purified by column chromatography on Sephadex G25. Binding of those iodothyronines to endogenous serum proteins was blocked by including 8-aniline-1-naphtalene sulphonic acid (ANSA) in the T₄ and T₃ assays and thymerosal in the rT₃ assay. Normal values were defined in 46 healthy euthyroid adults of both sexes: T₄ = 7,1 +- 1,3μg/dl; T₃ = 139 +- 35ng/dl and rT₃ = 18,0 +- 7,9ng/dl. (Author)

[en] The cross reactivity of T3 antibodies for T4 was studied with five T3 RIA kits. T4 used was provided from T4 RIA Kits (Abbot, Beckman, Corning). The results are shown on the table indicating the concentration of T3 or T4 required to displace 50% of the T3 125 from anti T3. The cross reactivity for T4 of T3 antibodies from Lepetit and Phadebas was the same and was smaller than cross reactivity with the other laboratories. In clinical practice serum T4 levels of hypo and euthyroid subjects are not so high to false T3 determination. In hyperthyroid subjects the diagnosis cannot be influenced by this cross reactivity. However, the study of the kinetic and monodeiodination of T4 into T3 may be wrong when T4/T3 ratio increases

[en] Triiodothyronine concentration was determined in human serum and in thyroid extracts by two radioimmunoassay technics. Both antibodies, radioactive T₃, stable T₃, protein-binding-hormone inhibitors, methods used to separate the free from the bound fractions were different. Each factor from a method was substituted to the homologue of the other method. The results occasionnally showed a variation of 32% in the first method and 50% in the second one. However the results gave a correct interpretation of the triiodothyronine values measured in human serum and in thyroid extracts

[en] In 21 cases of hypothyroidism, in 39 cases of hyperthyroidism, in 54 healthy subjects, in 23 pregnant women, and in certain internal diseases determinations of triiodothyronine were carried out in urine by radioimmunoassay. Anti-T₃ antibodies were obtained in rabbits and sheep immunized with a complex of bovine albumin with triiodothyronine ester. Labelled triiodothyronine of high specific activity was obtained by iodinating triodothyronine by the chloramine method. Determinations of triiodothyronine were performed in morning urine and the obtained values were calculated for one-hour excretion. In healthy subjects the excretion of T₃ was from 20 to 95 ng/hour, in hyperthyroidism it was significantly raised to from 120 to over 600 ng/hour, while in most cases of hypothyroidism it was decreased. In pregnancy the urinary excretion of T₃ was normal amounting to from 34 to 87 ng/hour, although in most cases the serum T₃ concentration was raised. In cases of anorexia nervosa and in obese starving subjects the excretion of T₃ fell significantly, and similarly low excretion was found in some cases of debilitating diseases and myocardial infarction. (author)

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