No abstract

The objective of the present work was to study all physiological relationships among selenium status (SeS), sex hormones secretion (SH), and thyroid metabolism (ThM) in healthy adolescent girls, at one time. Forty-four girls aged 13.4-16.6 years (mean age, 14.5 +/- 0.5 years) entered the statistical model. Parameters reflecting SeS: plasma selenium concentration (Se) and plasma glutathione peroxidase activity (GPX3); SH: serum estradiol (E2) and progesterone (P4); age of menarche (AoM); and ThM: thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), antithyroid peroxidase antibodies (anti-TPO) in serum, and thyroid volume (ThV), were determined, and the interactions between them were evaluated by means of the partial least squares method (PLS). PLS method was, for the first time, successfully applied to the problem of selenium and hormone interactions and revealed that selenium status and female reproductive system are interrelated and affect thyroid physiology in adolescent girls in the luteal phase. The strongest associations were revealed for the pairs of parameters, Se and fT4/fT3, Se and P4, the modest ones for the pairs, Se and ThV, P4 and fT4/fT3, Se and AoM, and P4 and AoM. There was no correlation between E2, GPX3, and TSH, and any other considered parameter. Se and P4 had the greatest influence on ThM parameters.

Possible interactions between selenium and iodine metabolism were 'investigated in 7to 16-yearold children with goiter (n = 136) living in southeastem Poland in iodine-deficient areas influenced by a sulfur indusry. The Se-iodine interactions in these children were. compared to the interactions in children from outside of that region (n = 38). Blood selenium (BSe) concentration and plasma glutathione peroxidase activity were much lower in the study group (64.1 * 15.

Recently published biochemical data suggest the significant role of selenium compounds as the adjuvants combined with L: -thyroxine therapy, which can reduce antithyroid peroxidase antibodies' (TPOAb) levels in patients with Hashimoto disease. The study was undertaken to document in a more detailed way the changes in parameters expressing the thyroid and ovarian function brought about by selenium supplementation (50-100 microg/day) in a woman undergoing autoimmune thyroiditis (AIT) therapy. This prospective observational case study lasted for 14 months plus additional 5 months as a follow-up period. Parameters reflecting selenium status, thyroid metabolism, and sex hormones secretion were determined at the onset and end of the study period, as well as in some of its middle points. During the supplementation trial, serum selenium (Se) increased by 45% and plasma glutathione peroxidase (GPX3) by 21%. TPOAb decreased by 76%. All other parameters also fluctuated during the supplementation period, but all results were always within normal physiological ranges. After withdrawal of the supplementation, the sharp fall of Se and GPX3 promptly occurred, and this phenomenon was accompanied with a marked increase in TPOAb. This report stresses the importance of selenium supplementation in AIT treatment. However, the efficiency and durability of the effect of Se supplementation on the TPOAb titer remain an open question. The clarification of mechanism(s) underlying Se interaction with autoimmune processes should throw new light on this issue.

Possible interactions between selenium and iodine metabolism were investigated in 7- to 16-year-old children with goiter (n = 136) living in southeastern Poland in iodine-deficient areas influenced by a sulfur industry. The Se-iodine interactions in these children were compared to the interactions in children from outside of that region (n = 38). Blood selenium (BSe) concentration and plasma glutathione peroxidase activity were much lower in the study group (64.1 +/- 15.7 microg/L; 111.0 +/- 27.6 U/L) than in the control group (85.3 +/- 19.6 microg/L; 182.4 +/- 35.6 U/L). Almost all of the data [plasma thyroid-stimulating hormone (TSH) concentration, plasma free thyroxine (fT(4)) concentration] fell within the reference limits. There was no statistically significant difference between the control and the study groups with respect to fT(4) and TSH. However, statistically significant differences of fT(4) and TSH in the study group were revealed between females belonging to the lower (n = 21; fT(4), 16.1 +/- 3.3 pmol/L; TSH, 1.83 +/- 1.05 mU/L) and upper Se quartiles (n = 24; fT(4), 14.5 +/- 2.2 pmol/L; TSH, 1. 26 +/- 0.90 mU/L), p < 0.05. Neither group differed in iodine in urine concentration, age, and body mass index. The difference in fT(4) concentrations can be attributed to an Se deficiency. The relationship exists only for females, which suggests a sex-linked hormonal response to concomitant Se and iodine deficiencies.ImagesFigure 1Figure 2