Endocrine Abstracts

The effect of age on thyroid function and hypothalamic–pituitary–thyroid axis have been studied. The objective of the study was to examine: correlation between triiodothyronine (T₃) and thyroxine (T₄) hormone levels, thyroid antibodies and thyroglobulin levels and old age; capability of TSH and prolactin (PRL) response to TRH, in TRH test depending on age and gender of the examines. We have tested 125 subjects, classified in 4 group. First, control group comprised of 42 health adults aged 20–40 years, 22 females and 20 males. The next three groups comprised of 83 healthy elderly persons, aged 40–70 years, 34 males and 49 females. All the patients had total T₃ and T₄, free T₃ and T₄, thyroid antibodies and thyroglobulin, TSH and PRL basal and after TRH stimulation determined. The results showed that with ageing, there was significant decrease of total and free T₄ values and slightly lesser intensity of T₃ in the male group, while in the female group, it was noted a mild increase of the total hormones values, but within the normal euthyrosis values with no changes in free hormone values. A significant fall of thyroglobulin antibodies with ageing was observed in the group of males and a considerable increase of thyroglobulin was shown in the group of females. Basal values of TSH and PRL remained within their normal values with ageing in both groups of examinees. Diminished sensibility in TSH response to the negative recurrent relation with the thyroid hormones, i.e. certain resistance of adenohypophysis to thyroid hormones was noted with ageing. TSH and PRL response in TRH test was diminished with ageing in the female group of examinees. It may be concluded that, despite of euthyroid status, TSH and PRL response has been changed in elderly examinees, more in women than man. The results also show difficulties in evaluating thyroid gland function in elderly examinees and TRH test limitations as diagnostic tool. In interpreting of the result of thyroid gland function tests, it is certainly necessary to take into consideration the age and gender of examinee. There is a need for a review of our strategy in thyroid gland function testing in elderly population.