Divergent expression of type 2 deiodinase and the putative thyroxine-binding protein p29, in rat brain, suggests that they are functionally unrelated proteins.

Deiodinases (D1, D2, and D3) are selenoproteins involved in thyroid hormone metabolism. Generation of the active hormone T(3), from T(4), is carried out by D1 and D2, whereas D3 degrades both hormones. The identity of the cloned D2 as a selenoprotein is well supported by biochemical and physiological data. However, an alternative view has proposed that type 2 deiodinase is a nonselenoprotein complex containing a putative T(4) binding subunit called p29, with an almost identity in sequence with the Dickkopf protein Dkk3. To explore a possible functional relationship between p29 and D2, we have compared their mRNA expression patterns in the rat brain. In brain, parenchyma p29 was expressed in neurons. High expression levels were found in all the regions of the blood-cerebrospinal fluid (CSF) barrier. p29 was present in different types of cells than D2, with the exception of the tanycytes. Our data do not support that p29 has a functional relationship with D2. On the other hand, expression of p29 in the blood-CSF barrier suggests that it might be involved in T(4) transport to and from the CSF, but further studies are needed to substantiate this hypothesis.

[Cerebral low T3 syndrome]. / Mozgovoi sindrom nizkogo T3.

The authors studied the time course of changes in the parameters of the cerebral thyronergic system (total and free triiodthyronine (T3) and thyroxin (T4), thyroxine-binding globulin (TBG), thyroid-stimulating hormone (TSH) by radioimmunoassay (Immunotech, Czechia; CIS, France), proinflammatory cytokine of TNF-alpha by enzyme immunoassay (Innogenetic, Belgium) in the blood and cerebrospinal fluid (CSF) in 59 patients (37 males and 22 females whose age ranged from 21 to 64 years) in acute subarachnoidal hemorrhage due to arterial aneurysmal rupture. On admission, the condition of 47 (79.7%) was rated as grades III-VI according to the Hunt-Hess scale, which was responsible for high mortality rates (33.89% in the assessment of outcomes according to the Glasgow outcome scale). The causes of death were ischemic and hemorrhagic insults, edema of the brain, cerebral stem wedging. Laboratory findings were analyzed in relation to the clinical condition of patients, outcomes, and the degree of secondary vasospasm assessed by Doppler transcranial study by the average blood flow velocity in the middle cerebral artery. They revealed a significant depression of thyroidal metabolism with developed the total low T3 syndrome just before surgical treatment in patients with deterioration in the early postoperative period. The significant correlations found by the authors between the decreased blood T3 and TSH levels and 1) the severity of neurological disorders; 2) the degree of vasospasm, and 3) the outcome of disease, as well as negative correlations of elevated TNF-alpha levels not only in the blood, but also in CSF with the content of CT3, CT4 and with the severity of neurological symptomatology are indicative of the development of isolated syndrome in the brain, which is characterized by specific thyroidal metabolic disorders, which the author propose to call the cerebral low T3 syndrome (by taking into account the presence of the autonomic systems of thyroidal homeostatic provision).

Value of serum transthyretin measurements in the assessment of marginal protein-energy malnutrition in rats.

The influence of a wide range of protein and/or energy intakes on the serum level of rat transthyretin was studied. Young and adult rats were fed ad libitum diets containing 18, 9, 6, 4 and 0.5% protein (wt/wt) or were fed a control diet in restricted amounts. The transthyretin level was lower in young rats and was normal or slightly higher in adult rats fed low protein diets than in those fed the 18% protein diet. It was decreased with decreasing energy intake in all energy-restricted rats. Moderate energy restriction in rats fed equivalent amounts of protein also lowered the transthyretin level. Rats with similar body weights and similar protein intakes showed marked differences in serum transthyretin level, depending on the amount of energy consumed. Serum transthyretin changes were discussed in relation to the level of transthyretin in cerebrospinal fluid and to the serum concentration of albumin, transferrin and thyroid hormones. The results show that serum transthyretin is more closely related to the protein and energy intakes than to the protein and energy content of the diet. Our results indicate that serum transthyretin measurement is a reliable marker in the detection of early moderate and severe protein-energy restriction.