Deficiency in vitamin D plays a role in the onset and development of insulin resistance (IR) and type 2 diabetes (T2DM). A normal level of vitamin D is able to reduce low grade inflammation, which is a major process in inducing insulin resistance. It is also engaged in maintaining low resting levels of reactive species and radicals, normal Ca2+ signaling, a low expression of pro-inflammatory cytokines but increased formation of anti-inflammatory cytokines. Vitamin D is also able to prevent hypermethylation (of DNA) and consequent functional inactivation of many genes, as well as other epigenetic alterations in β cells and in other insulin-sensitive peripheral tissues, mainly liver, adipose tissue and muscle. Vitamin D deficiency thus belongs to key factors accelerating the development of IR and consequently T2DM as well. However, vitamin D supplementation aimed at the control of glucose homeostasis in humans showed controversial effects. As a result, further studies are running to gain more detailed data needed for the full clinical utilization of vitamin D supplementation in the prevention and treatment of T2DM. Until new results are published, supplementation with high doses of vitamin D deficiency is not recommended. However, prevention of vitamin D deficiency and its correction are highly desired.
- Klíčová slova
- diabetes mellitus type 2, insulin resistance, vitamin D deficiency,
- MeSH
- diabetes mellitus 2. typu krev etiologie patofyziologie prevence a kontrola MeSH
- inzulinová rezistence MeSH
- lidé MeSH
- nedostatek vitaminu D krev komplikace farmakoterapie patofyziologie MeSH
- vitamin D krev terapeutické užití MeSH
- vitaminy krev terapeutické užití MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- vitamin D MeSH
- vitaminy MeSH
This article discusses the conditions that may lead to a phenomenon called dysthyronemia. Here, the thyroid gland has concentration of thyrotropin in circulation within the reference range, but the concentrations of free or total fractions of thyroid hormones are outside the reference range. Normal values of thyrotropin (TSH) and increased values of THs are referred to as hyperthyroxinemia, while normal values of thyrotropin and decreased values of thyroid hormone are hypothyroxinemia. As shown by our observations, it is a relatively frequent situation in the parallel determinations of TSH and free thyroxine, when results verging on hyperthyroxinemia were found in 7% of cases (6.74%, n=259,590), and also in the parallel sets of TSH and total triiodothyronine when hypotriiodothyroninemia reached 8.5% (8.48%, n=73,143). We are assuming that the main cause of hyperthyroxinemia in the free thyroxine and TSH system is the presence of autoantibodies against thyroxine in patients with autoimmune thyroid disease. The reason of hypotriiodothyroninemia in the system of triiodothyronine and TSH is a decreased concentration of thyroid binding globulin in postmenopausal women. Manufacturers of immunoanalytical kits should take into account the potential adverse effects of autoantibodies against thyroid hormones when measuring the results of immunoassay determination of the free fraction of these hormones.
- MeSH
- dospělí MeSH
- hormony štítné žlázy krev MeSH
- hypertyroxinemie krev diagnóza MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- proteiny vázající thyroxin metabolismus MeSH
- referenční hodnoty MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- štítná žláza metabolismus patologie MeSH
- thyreotropin krev MeSH
- thyroxin krev MeSH
- trijodthyronin krev MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- hormony štítné žlázy MeSH
- proteiny vázající thyroxin MeSH
- thyreotropin MeSH
- thyroxin MeSH
- trijodthyronin MeSH
The data on hormonal steroids in the human seminal plasma and their role in spermatogenesis are summarized. The seminal steroid levels need not correlate with the blood plasma levels. The recent reports showed that androgen, especially dihydrotestosterone, and the estrogen levels in the seminal fluid may be used as the markers of spermatogenesis impairment. The estradiol concentration in the seminal plasma was higher than in the blood plasma, and its levels were significantly increased in men with impaired spermatogenesis. A good indicator for predicting the normal spermatogenesis, therefore, seems to be the testosterone/estradiol ratio. The seminal plasma also contains significant amounts of cortisol, which influences the androgen biosynthesis through its receptors in the Leydig cells. The local balance between cortisol and inactive cortisone is regulated by 11β-hydroxysteroid dehydrogenase, the activity of which may be affected by the environmental chemicals acting as the endocrine disruptors (EDCs). These compounds are believed to participate in worsening the semen quality - the sperm count, motility, and morphology, as witnessed in the recent last decades. As to the steroids' role in the testis, the EDCs may act as antiandrogens by inhibiting the enzymes of testosterone biosynthesis, as the agonists or antagonists through their interaction with the steroid hormone receptors, or at the hypothalamic-pituitary-gonadal axis. Surprisingly, though the EDCs affect the steroid action in the testis, there is no report of a direct association between the concentrations of steroids and the EDCs in the seminal fluid. Therefore, measuring the steroids in the semen, along with the various EDCs, could help us better understand the role of the EDCs in the male reproduction.
- MeSH
- endokrinní disruptory metabolismus MeSH
- lidé MeSH
- rozmnožování MeSH
- sperma chemie cytologie metabolismus MeSH
- spermatogeneze * MeSH
- steroidy analýza metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- endokrinní disruptory MeSH
- steroidy MeSH
