A study of the characteristics of hepatic iodothyronine 5'-monodeiodinase in various vertebrate species.

Rat type I iodothyronine 5'-monodeiodinase (5'-MD) has recently been shown to be a selenium-containing enzyme. In the present study we compared the characteristics of the 5'-MD from liver microsomes of rat, mouse, guinea pig, man, beef, pig, sheep, and chicken. Aurothioglucose (ATG), a known potent inhibitor of selenium-containing enzymes, was a consistent, very potent inhibitor of 5'-MD activity in all species studied, with a 50% inhibitory dose in the narrow range of 5.

A radioimmunoassay for measurement of 3,5,3'-triiodothyronine sulfate: studies in thyroidal and nonthyroidal diseases, pregnancy, and neonatal life.

A highly sensitive, specific, and reproducible RIA has been developed to measure T3 sulfate (T3S). Only T4 sulfate cross-reacted significantly (approximately 3%) in the RIA; rT3 sulfate, T4, T3, rT3, and diiodothyronine cross-reacted less than 0.01%.

A study of the characteristics of the rat placental iodothyronine 5-monodeiodinase: evidence that it is distinct from the rat hepatic iodothyronine 5'-monodeiodinase.

Recent studies have demonstrated that rat liver type I iodothyronine 5'-monodeiodinase (5'-MD) characteristically contains selenocysteine. The present study was undertaken to characterize rat placental type III iodothyronine 5-MD and to compare it with 5'-MD. Solubilized rat placental microsomes were delipidated by carboxymethyl cellulose-Sephadex chromatography.

A study of the serum concentration of tumor necrosis factor-alpha in thyroidal and nonthyroidal illnesses.

We have studied serum concentrations of immunoassayable tumor necrosis factor-alpha (TNF alpha) and iodothyronines (T4, T3, and rT3) in normal subjects (n = 16) and patients with nonthyroidal illnesses (NTI; n = 13), hyperthyroidism (n = 10), and hypothyroidism (n = 9). The mean (+/- SEM; femtomoles per mL) serum concentration of TNF alpha was 45 +/- 4.3 in normal subjects, 84 +/- 38 in NTI, 54 +/- 6.

Inhibition of nuclear T3 binding by fatty acids.

Studies were performed to evaluate a possible modulatory role of lipids on the binding of T3 to rat liver nuclear receptors in vitro. Unsaturated fatty acids were potent inhibitors of the binding of [125I] T3 to isolated rat liver nuclei. Doses (in mumol/L) causing a 50% inhibition of nuclear T3 binding were 10 for palmitoleic acid, 11 for linoleic acid, 22 for oleic acid, 24 for arachidonic acid, and 37 for linolenic acid.