The Inter‐relationship of Thyroid Hormones, Vitamin a and Their Binding Proteins Following Acute Stress

Abstract

The effects of surgical stress on the metabolism of the retinol-binding-protein-thyroxine-binding-prealbumin complex were investigated. The immediate postsurgical period was characterized by a rapid decline in the serum concentration of retinol, retinol binding protein and triiodothyronine and an increase in the 24 h urinary excretion of retinol, retinol-binding-protein and thyroxine. Similar, but less pronounced, changes were seen in other subjects suffering acute myocardial infarction but were not observed in normal healthy euthyroid males or in pre-operative euthyroid patients. The preparation of specific anti-retinol binding protein anti-serum and the use of this in 'monorocket' immunoelectrophoresis are also described.

Model-based compartmental analysis indicates a reduced mobilization of hepatic vitamin A during inflammation in rats

“…However, these studies have had difficulty assessing which is the prime driver because of the close interaction between VA deficiency and infection-induced inflammation. Even clinical studies, in which serial measurements of plasma retinol or urinary RBP have been used to monitor the effect of infection-induced inflammation, have not clearly determined the cause and consequences of hyporetinolemia (31,32). Experimental studies in animals have shown without exception that plasma retinol can be reduced by a variety of immune stressors ranging from viral infections and turpentine injections to prolonged immobilization (32)(33)(34)(35)(36).…”

Impact of disease on markers of micronutrient status

“…However, infection has pronounced effects on thyroid hormones, since they are transported in the blood by the negative acute-phase protein, transthyretin (TTR). The synthesis of TTR is markedly suppressed by infection (Ramsden et al 1978;Dickson et al 1982), thus thyroid hormone levels measured in communities where infection is common should be interpreted with caution. Whether such measurements can be better assessed using other acute-phase proteins to detect infection, as suggested for retinol, remains to be investigated.…”

Change in vitamin A content in tissues of rats fed on a vitamin A-free diet.

“…Evidence has been accumulated to indicate that the metabolism of vitamin A is modulated under various nutritional, hormonal and physiological conditions (2)(3)(4)(5)(6)(7)(8)(9). Many studies along these lines have been carried out by following changes in the tissue distribution of cold or radioactive retinoids.…”