Triiodothyronine Turnover in Hospitalized Psychogeriatric Patients†

Abstract

In a group of 12 hospitalized psychogeriatric patients, the fractional triiodothyronine (T3) turnover rate was significantly higher than in healthy control subjects of the same age, whereas the thyroxine (T4) turnover rate and other aspects of pituitary-thyroid function were virtually similar in both groups. Despite the presence of manifestations of sympathetic overactivity or hypermetabolism, the patients did not have true hyperthyroidism, as verified by the laboratory findings and the results of antithyroid treatment. The increases T3 turnover in aged hospitalized patients with brain disorders may be a compensatory mechanism which develops under these particular circumstances in order to maintain neurohormonal homeostasis. An alternate possibility is that the increased T3 turnover is secondary to hyperkinesis.

Bromocriptine: Effect on Serum Prolactin and Growth Hormone in Psychogeriatric Hospital Patients

“…The interesting possibility of an HGH‐thyroid hormone interaction has been raised as a result of the findings of this study with bromocriptine. As we have shown recently (18) in 12 hospitalized psychogeriatric patients, triiodothyronine (T3) turnover was significantly increased, regardless of the psychiatric diagnosis. Within the age range of 65 to 93 years, the HGH levels seem to be unrelated to age, sex or physical activity.…”

A Psychogeriatric Assessment Program. II. Clinical and Laboratory Findings†

“…The routine clinical examination of psychogeriatric patients often results in the impression that they represent a hyperthyroid or sympathicotonic (hyperadrenergic) type. In support of this is our recent finding that the triiodothyronine (T 3 ) turnover rate in 12 psychogeriatric patients, regardless of the psychiatric diagnosis, was higher than in mentally healthy controls of the same age, while the thyroxine (T 4 ) turnover rate and the serum values for T 4 , T 3 , TSH (thyrostimulating hormone) and PBI (protein‐bound iodine) were normal (2, 3).…”

“…Differences in biologic functions between the diagnostic groups were less pronounced than might have been expected on the basis of our earlier study (8), but this was probably largely due to the absence of a healthy old control group in the present comparison (Table C). An additional reason, particularly with regard to thyroid function, is that much greater group differences are found in kinetic studies of T 3 than if single levels of T 4 and related items are compared (2, 3).…”

A Psychogeriatric Assessment Program. IV. Interdisciplinary Aspects*

“…Another aspect has become evident in some of the foregoing discussions — something one might call “off‐shoots” or secondary developments which proceed in their own right. This applies to Hontela and associates’ studies of glucose metabolism (14, 15) and of triiodothyronine turnover (4, 5, 16). In addition, an epidemiologic study of elderly people in our community is now being carried out by Mrs. D. Ihra and collaborators.…”

“…The same may be true for the plasma levels of thyroxine (T 4 ) in the present studies. It appears, however, that other indicators of thyroid function such as triiodothyronine (T 3 ) turnover are more sensitive, as discussed by Hontela et al (4, 5).…”