We examined insulin sensitivity and secretion, together with the levels of selected glucoregulatory hormones, in 15 female patients with severe hypothyroidism (H) and during subsequent thyroid hormone replacement therapy (HRT) using the euglycaemic hyperinsulinaemic clamp technique. Insulin action, as evaluated by glucose disposal, the insulin sensitivity index, and fasting post-hepatic insulin delivery rate were established. The basal levels of insulin, C-peptide and counter-regulatory hormones were measured in basal condition. In H, glucose disposal (p<0.01), the insulin sensitivity index (p<0.01) and post-hepatic insulin delivery rate (p<0.05) were significantly lower than during HRT. No significant changes in the levels of fasting insulin and C-peptide were observed. The levels of counter-regulatory hormones in patients with H were significantly higher than during HRT (glucagon, p<0.05; epinephrine, p<0.01; cortisol, p<0.05; growth hormone, p<0.05). In H, an inverse correlation between insulin sensitivity and insulin secretion was observed (p<0.05). Cortisol was the most important factor affecting the variability of insulin sensitivity values, regardless of thyroid function (p=0.0012). In conclusion, H altered both insulin sensitivity and the levels of selected counter-regulatory hormones. The situation was restored by HRT, as manifested not only by normalisation of insulin sensitivity, secretion and levels of glucoregulatory hormones, but also by improvement of their relationships.
Elevated titers of antibodies against different antigens of Epstein-Barr virus (EBV) are found in some immunodeficient states, malignancies or in autoimmune disorders. We examined EBV serology in the group of 22 patients with autoimmune thyroiditis as compared with the group of 35 healthy volunteers. Titers of antibodies against viral capsid antigen (IgG-VCA) were more often found in the group of patients than in the control group (p = 0.000 35 for younger than 40 years and p = 0.00115 for older than 40 years) and the positivity of antibodies against early antigen (IgG-EA-D/DR) was also significantly more often found in the group of patients (p = 0.0031 and p = 0.0019 respectively) than in the control group.
The Czech Republic has a long history of iodine deficiency. Salt iodization was introduced in 1947, followed by a progressive correction of iodine deficiency. The present study reports the changes in the status of iodine nutrition and of thyroid function in the country from 1994 to 2002. The study included 29612 individuals, aged 0 to 98 years, including 5263 individuals randomly selected from the general population and 24349 individuals who attended the Institute of Endocrinology of Prague (hospital population). Urinary iodine was determined in all individuals. Measurements of serum thyrotropin (TSH), free thyroxine (FT4), free triiodothyronine (FT3), and thyroglobulin (Tg), were taken in 8544 to 19060 individuals. The iodine content of table salt was measured in 1130 samples. The median urinary iodine in the general and hospital populations were not significantly different. They progressively increased with time, starting from values indicating mild iodine deficiency (88-95 microg/L) prior to 1997, reaching the critical threshold of 100 microg/L in 1998, and optimal values between 120-140 microg/L since 2000. There was only a low and not significant positive correlation between the iodine content of salt and the urinary iodine. In contrast, urinary iodine showed marked seasonal changes, with the highest values during winter, when livestock were supplemented by mineral tablets containing iodine. Variables exploring thyroid function were all situated within the normal range in adults but another study (results not reported) has shown the persistence of slightly elevated TSH in neonates. The correction of iodine deficiency was not accompanied by unfavorable side effects. In conclusion, the Czech Republic has achieved sustainable elimination of iodine deficiency. Salt iodization has been a determining, but not the only, factor responsible for the success. Iodine supplementation of livestock and increased consumption of milk rich in iodine have probably played a determining role. Neonatal thyroid screening could constitute the major monitoring tool in order to insure sustainable elimination of iodine deficiency in the Czech Republic.
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