Age Dependent Changes in Iodine Metabolism and Thyroid Function

Abstract

Absolute iodine uptake (AIU), serum thyroxine (T4), free T4 index and serum triiodothyronine (T3) were studied in 48 women and 63 men aged 20 to 90 years. AIU decreased with age in both sexes to values in the oldest age groups of about 60 % of the values in the youngest age groups. AIU values for females were about 75 % of the values for males. Free T4 index was found to be unaltered with increasing age but serum T3 decreased with age. These findings and the previous demonstrated decrease in T4 degradation rate seem consistent with the assumption that T4 and T3 production decreases with advancing age.

Effects of exercise upon circulating thyroxine serum and hepatic lipid concentrations, heart, and seminal vesicles in rats and of age and exercise upon circulating thyroxine in humans

“…Age is not seen to have an effect on the thyroid indices of the sedentary men (Table 24). This was to be expected since earlier studies, such as the one by Hansen et (1975), showed no change with increasing age in circulating thyroxine levels. With the joggers the thyroxine levels and the FTI values are higher in the 30 year old group than in the 50 year old group (Table 25).…”

Fine structural aspects on the cold follicles in the aged mouse thyroid.

“…Concerning the age changes in the structure and function of the thyroid gland, there are numerous papers dealing with the accumulation of lipofuscin (IVES et al, 1975), the decrease in thyroxine degradation rate (GREGERMAN et al, 1962), the decrease in absolute iodine uptake (HANSEN et al, 1975), the decrease in 131I uptake and supression of 131I release (WILANSKY et al, 1957), the decrease in effect of TSH stimulation in terms of AMP accumulation and thyroid hormone release (SARTIN et al, 1977) and so on. However, fine papers dealing with the age change of the functional morphology of this gland are quite few in number.…”

“…The present paper shows that the increase in number of large inactive follicles occurs as an aging change, though about 80% of follicles are well-reactive to exogenous TSH. It is well known from the biochemical data by numerous investigators that the activity of the whole thyroid is diminished through the aging process (QUIMBY et al, 1950;VERZAR and FREYDBERG, 1956;WILANSKY et al, 1957;ELEFTHERIOU, 1975;HANSEN et al, 1975;SARTIN et al, 1977). Some of the large follicles with large lumina react to repeated injections of TSH.…”

Effects of exercise upon circulating thyroxine serum and hepatic lipid concentrations, heart, and seminal vesicles in rats and of age and exercise upon circulating thyroxine in humans

“…These histological changes are accompanied by decreases in both the thyroid secretion rate (Grad and Hoffman, 1955;and Story, 1972) and the uptake of iodine by the thyroid (Wilansky et al, 1957;Gaffney et aj_., 1962;and Hansen et , 1975). A number of…”

“…This problem was overcome by Hansen et (1975). They calculated the concentration of plasma inorganic iodide and multiplied it by the thyroidal plasma radioiodide clearance to give a new value, the absolute iodide uptake.…”