ACTA ENDOCRINOLOGICA (BUC)

Objective. Personal discrepancies in gastrointestinal physiology might influence responses to GH suppression during OGTT. We aim to compare growth hormone (GH) response during oral glucose tolerance test (OGTT) and intravenous glucose tolerance test (IVGTT). Methods. Data of 18 healthy volunteers were analyzed in the study. Subjects were firstly evaluated with standard 75-g OGTT. In subjects with serum glucose <100 mg/dL at basal state and <140 mg/dL at 120th minute of oral loading, IVGTT was performed after at least 3 days. Serum glucose, insulin and GH levels were measured during two tests. Results. Basal GH levels had a wide distribution ranging from 0.00005 μg/L to 0.768 μg/L (median 0.0145 μg/L). Mean nadir GH level during OGTT was obtained at 60th minute and it was 0.0376 μg/L(range 0.00011-0.387, median 0.0016 μg/L, SD: 0.095, SEM: 0.038). Nadir GH level during IVGTT was observed at 10th minute and it was 0.112 μg/L(range 0.0005-0.770 μg/L, median 0.0053 μg/L, SD: 0.242, SEM: 0.057). There was a statistically significant difference between nadir GH levels obtained during IVGTT and OGTT (p=0.028). Conclusions. We found that mean nadir GH level was significantly higher during IVGTT in healthy subjects. This is a preliminary study and further large scale studies are required to suggest that IVGTT may be used in the diagnosis and follow-up of patients with acromegaly as an alternative to or instead of OGTT.

Context. Exenatide is a Glucagon-like Peptide-1 receptor agonist, which is widely used for type 2 diabetes mellitus (T2DM). Limited and conflicting results are present about the effect of exenatide on the thyroid gland. Objective. The aim of this study was to evaluate the effect of exenatide treatment on structural and functional features of the thyroid gland in patients with T2DM. Design. The study was a prospective study, performed between 2015 and 2017. The laboratory values and thyroid ultrasonography features were compared before and after exenatide treatment. Subjects and Methods. The study included 39 obese diabetic patients. After inclusion to the study exenatide was started and patients were followed up for 6 months. Total thyroid volume, thyroid function tests, serum carcinoembryonic antigen (CEA) and calcitonin levels, the size and appearance of thyroid nodules were compared between baseline and after 6 months of treatment. Results. Exenatide at a dose of 5μg bid was started, increased to 10 μg bid after 4 weeks. We found a statistically significant decrease in thyroid volume (p=0.043) and serum thyroid stimulating hormone (TSH) levels (p=0.007), whereas serum ATPO. ATGl, fT4, fT3, CEA and calcitonin levels did no change with 6 months of exenatide treatment. There were no significant differences in the size and appearance of the thyroid nodules with treatment. The thyroid volume decrease was not correlated with TSH, body mass index and HbA1c reduction. Conclusion. Exenatide treatment for 6 months decreased serum TSH levels and thyroid volume, but had no effect on thyroid nodules and serum CEA and calcitonin levels.

Context. The metabolic effects of primary hyperparathyroidism (PHPT) causing increased cardiovascular morbidity have begun to gain importance in medical science, and the number of studies investigating glucose metabolism disorders in asymptomatic PHPT patients is rare. Objective. To evaluate the relationship between glucose metabolism disorders and calcium, phosphorus and parathyroid hormone concentrations in asymptomatic PHPT patients. Subjects and Methods. Fifty-five asymptomatic PHPT patients were included into the study. Control group consisted of 55 normocalcemic cases. Oral glucose tolerance test (OGTT) of 75 g was performed with patients and controls. Insulin resistance was calculated by HOMA index. Results. No significant difference was present between groups regarding fasting plasma glucose, basal insulin and HOMA levels. Glucose levels measured at minutes 30, 90 and 120 after OGTT were higher in patients than in controls (p=0.041, p=0.025 and p=0.001, respectively). No individuals in both groups were diagnosed with diabetes mellitus. While impaired glucose tolerance was detected in six patients with asymptomatic PHPT, no impaired glucose tolerance was determined in controls. A positive correlation was found between serum calcium levels, and fasting plasma glucose and OGTT glucose levels were measured at minutes 60, 90 and 120. Mean fasting plasma glucose was significantly higher in patients with serum calcium levels ≥ 10.5 mg/dL than those with serum calcium levels <10.5 mg/dL (p=0.008). No significant correlation was detected between serum phosphorus and parathyroid hormone levels, and glucose levels were determined in OGTT and HOMA index. Conclusion. Increased levels of serum calcium affect glucose metabolism, so leading to glucose intolerance.

Background. Antineutrophil cytoplasmic antibodies (ANCA) positivity is usually determined in vasculitis of medium and large arteries. In literature, data related to the prevalence of ANCA positivity and the development of antibodies after antithyroid therapy in Graves’ disease are quite rare. Aim. To investigate the titers of myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA in Graves’ patients treated with propylthiouracil (PTU) and to determine the factors that may contribute to ANCA positivity. Subjects and Methods. Fifty-two Graves’ patients treated with propylthiouracil (PTU) were included into the study. The control group consisted of 37 healthy subjects. MPO-ANCA and PR3-ANCA titers were measured in both groups. Results. Mean titer of PR3-ANCA in Graves’ group was significantly higher than in controls (p=0.025), but no significant difference was found in the titer of MPOANCA between two groups (p=0.060). A positive correlation was observed between PR3-ANCA titer, and anti-thyroid peroxidase antibody and anti-thyroglobulin antibody levels in Graves’ patients (p=0.001, r=0.447 and p=0.030, r=0.310, respectively). PR3-ANCA titer in anti-thyroglobulin antibody positive patients was higher than those with negative antibody (p=0.018). A positive correlation was detected between the duration of treatment and PR3-ANCA titer (p=0.024, r=0.314). Both MPO-ANCA and PR3-ANCA were positive in two Graves’ patients, while only MPO-ANCA was positive in two patients. No signs of vasculitis in ANCA positive patients were observed. Conclusion. Propylthiouracil (PTU) may cause ANCA positivity, but no vasculitis may develop in most of the cases. A correlation was determined between PR3- ANCA titer, and thyroid autoantibodies and the duration of treatment.