Publications by authors named "Vondra K"

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 Ca signaling, a low expression of pro-inflammatory cytokines but increased formation of anti-inflammatory cytokines.

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Objective: Patients with type 2 diabetes (T2DM) generally experience a higher incidence of cancer. However, the association between T2DM and thyroid cancer is inconclusive.

Methods: Case-control prospective study, 722 patients were screened for T2DM and prediabetes (PDM) and underwent thyroid ultrasound and biochemical tests.

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Anti-lipolytic drugs and exercise are enhancers of growth hormone (GH) secretion. Decreased circulating free fatty acids (FFA) have been proposed to exert ghrelin-GH feedback loop after administration of an anti-lipolytic longer-acting analog of nicotinic acid, Acipimox (OLB, 5-Methylpyrazine-2-carboxylic acid 4-oxide, molecular weight of 154.1 Da).

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In women with chronic autoimmune thyroiditis and vitamin D deficiency we have found reference levels of relevant metabolic-hormonal parameters except for parathormone and total calcium. Three months supplementation with vitamin D (4300 IU/day, cholekalciferol) did not lead to significant changes of investigated hormonal parameters, while the levels of parathormone and calcium reached normal levels. However, a correlation analysis revealed marked changes in mutual relations.

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Resistance to steroid hormones presents a serious problem with respect to their mass use in therapy. It may be caused genetically by mutation of genes involved in hormonal signaling, not only steroid receptors, but also other players in the signaling cascade as co-regulators and other nuclear factors, mediating the hormone-born signal. Another possibility is acquired resistance which may develop under long-term steroid treatment, of which a particular case is down regulation of the receptors.

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From the recent literature data it may be concluded that vitamin D deficiency is associated with increased risk of thyroid autoimmunity development and thus should be considered as an additional important risk factor for both chronic autoimmune thyroiditis (postpartum thyroiditis including) and Graves´ disease. A higher risk of Graves´ disease development is also associated with several polymorphisms in the gene encoding for vitamin D binding protein and for the specific receptor of active form of vitamin D - 1,25-(OH)2D3 in the respective target cells. Whether careful supplementation with vitamin D aimed to normalize low 25(OH)D levels brings preventive or therapeutic effect is subject to further research.

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Introduction: In patients with type 1 and 2 diabetes mellitus only rare data concerning the status of iodine supplementation and impact of possible iodine deficiency is available.

Aim: To get basic information about (a) state of supply with iodine in patients with type 1 diabetes mellitus (DM1T), (b) the difference from non-diabetic population, (c) possible association of iodine saturation with some clinical and laboratory features of the diabetic syndrome, including the state of thyroid gland.

Subjects And Methods: We examined 54 men and 51 women treated with DM1T in a cross-sectional study.

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Unlabelled: Excessive hepatic glucose production resulting from dysregulated glucagon secretion associated with inappropriate fasting and postprandial hyperglucagonemia is common feature in type 2 diabetes (DM2T). The effects of some currently widely used anti-diabetic agents, especially concerning metformin, GLP1 agonists and inhibitors of DPP4, comprise partial supression of glucagon secretion and/or action. Complete supression of glucagon action is recently widely investigated in experiments, and also results of phase 1 and 2 of the clinical trials are available.

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In this review we summarize recent opinions on the possible role of vitamin D in the risk of thyroid diseases development. It may be concluded from the available data that vitamin D deficiency, particularly levels below 12.5 ng/ml should be considered as an additional, but important risk factor for development of thyroid autoimmunity, both chronic autoimmune thyroiditis and Graves' disease.

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The aim of our work was to provide data from women of fertile age with type 1 diabetes mellitus about the endogenous androgens and on their relations to the parameters of diabetes control. Forty-two women were examined, they did not use contraceptives for at least three months prior to the examination. A multivariate regression analysis showed that the daily insulin dose, the fasting glycemia and the HbA1c values and patient's age correlated negatively with dehydroepiandrosterone sulfate, dehydroepiandrosterone and prolactin levels.

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The aim of this study was to look for changes in the daily profile of steroid hormones after standardized food intake. Eight young women not taking contraceptives were followed from 5:30 a.m.

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Addiction to tobacco results in an imbalance of endocrine homeostasis in both sexes. This can also have impacts on fertility problems. The male reproductive system is less susceptible than that of females, with a worsening spermiogram in smokers, the most cited effect in the literature.

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The influence of steroid hormones on food intake is well described. However, there are only a few studies on the effect of food intake on steroid levels. The study involved eight non-smoker women (average age 29.

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Smoking represents the most widespread substance dependence in the world. Nicotine alters women hormonal homeostasis. Women smokers have higher testosterone and lower estradiol levels throughout life compared to nonsmokers.

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Eating disorders such as anorexia (AN) and bulimia nervosa (BN) are characterized by abnormal eating behavior. The essential aspect of AN is that the individual refuses to maintain a minimal normal body weight. The main features of BN are binge eating and inappropriate compensatory methods to prevent weight gain.

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Objective: Free fatty acids (FFA)-adrenocorticotropin (ACTH) feedback loop between adipose tissue and the hypothalamic-pituitary centers in the brain has been suggested to be affected by the exercise and by administration of anti-lipolytic drugs. Also leptin may be affected by exercise. Dysfunction of FFA-leptin-ACTH secretion might be involved in binge eating and subsequent purging as is the case in bulimia nervosa (BN).

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Chronic smoking can cause imbalance in endocrine homeostasis and impairment of fertility in both sexes. The male reproductive system is more resilient, still the literature provides conflicting results about the influence of smoking on the steroid hormone levels. The data about smoking cessation are limited; there has not yet been a study primarily focused on changes in steroids levels.

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Based on experience from experimental and human studies, vitamin D can be considered an important factor lowering the risk of diabetes mellitus type 1 and 2. The mechanism consists in the direct influence of vitamin D via nuclear receptors on genes coding proteins associated with normal function of B cells of Langerhans islands and genes coding proteins ensuring normal function of the immune system. There is also an indirect influence via regulation of homeostasis of calcium.

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The association of transcription factor 7-like 2 (TCF7L2) gene variants with the pathogenesis of T2D, gestational diabetes and polycystic ovary syndrome (PCOS) was examined. The study involved 1460 individuals: 347 T2D patients (D); 261 gestational diabetics (G); 147 offspring of T2D (O); 329 women with PCOS, and 376 controls (C). The SNPs: rs7901695; rs7903146; rs12255372 in the TCF7L2 gene were genotyped.

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Background: Neuropeptide Y (NPY) is an important central orexigenic hormone predominantly produced by the hypothalamus, and recently found to be secreted in adipose tissue (AT). Acipimox (Aci) inhibits lipolysis in AT and reduces plasma glycerol and free fatty acid (FFA) levels. Exercise and Aci are enhancers of growth hormone (GH) and NPY secretion and exercise may alter leptin levels.

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Objective: Ghrelin is predominantly produced by the stomach and the growth hormone (GH)-ghrelin feedback loop between the stomach and the pituitary gland has recently been suggested. The disruption of the gut-brain axis might be involved in bulimia nervosa (BN).

Methods: We investigated responses of plasma GH, ghrelin, and neuropeptide Y (NPY) concentrations to exercise or to exercise after the administration of the antilipolytic drug Acipimox (Aci) in seven BN patients and seven healthy women (C).

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Cortisone acetate test was performed in twelve young adult patients with diabetes mellitus type 1, after dexamethasone administration to suppress endogenous cortisol production. Previous screening revealed that all of the subjects had peak cortisol responses in the range from subnormal to normal, as determined by a low-dose Synacthen test. The aim was to find out whether these patients would exhibit different conversion of cortisone to cortisol by 11beta-hydroxysteroid dehydrogenase.

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In 75 young adults with diabetes mellitus type 1 (DM 1) we have performed a cross-sectional study to gain more information about their adrenocortical function. We have found in a surprisingly large portion of patients (25%) a subnormal response (<500 nmol/L, low responders) of the serum cortisol during low-dose Synacthen test, accompanied by significantly decreased stimulated values of aldosterone and salivary cortisol. Basal serum cortisol, aldosterone, and dehydroepiandrosterone sulphate (in women only) were significantly reduced in low responders as well, while ACTH, cortisol binding globulin, plasma renin activity, urinary free cortisol/24h, and salivary cortisol did not differ.

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Adrenocortical disorders represents an important problem in patients with type 1 diabetes mellitus and therefore many physicians are concerned with this issue. The causes of adrenocortical insufficiency include both autoimmunity and dysregulation related to insufficiently compensated diabetes. Early diagnosis of hypocorticism remains doubtful.

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