[Age-related changes in peripheral thyroid parameters, it hypophyseal regulation and relation to fat metabolism]

In 50 women and 57 men aged 20 to 80 years serum levels of T3, T4 and rT3 as well as TSH levels before and after intravenous application of TRH and serum triglycerid- and cholesterol-levels were determined. Regressions and multiple regressions were calculated with Broca-Index, and age. Serum-T3 are significantly lower in old age than in younger people. In men serum T4-levels remain unchanged in old age, in women a significant rise can be observed. With rising age TBK rises in men and falls in women. Women older than 50 years have significantly higher Serum-triglycerid- and cholesterrol-levels, Broca-Index being unchanged, than younger women. In men no remarkable change of these parameters could be detected. Calculating multiple regressions we found significant relations parameters could be detected. Calculating multiple regressions we found significant relations of T3-serum levels to either age and TBK or age and T4, as well as relations of rT3 serum levels to age and T4 levels in men and women. Only in men TSH-secretion following intravenous TRH application is related to age and serum-T3, or age and T4-serum levels or age and rT3-levels in serum. Broca-Index in men is related to age and T3-levels in serum. In both sexes serum-triglycerid-levels are significantly related to Broca-Index and rT3-levels or Broca-Index and T4-concentration in serum. Serum-cholesterol or triglyceride-levels correlate in women with age and T3-serum-concentrations. With increasing age in men and women hypothyreodism seems to be increasing.