ABSTRACT
OBJECTIVE: Glucagon-like peptide-1 (GLP-1) analogues are now widely used for the treatment of type 2 diabetes mellitus (DM). Many binding sites for GLP-1 have been demonstrated in the specific tissue compartments of organs in-cluding the brain and thyroid. The aim of this study was to investigate the effect of exenatide treatment on thyroid-stimulating hormone (TSH) and thyroid volume in diabetic patients without thyroid disease. MATERIAL AND METHODS: The study included 46 diabetic patients without thyroid disease who were receiving exenatide treatment. Comparisons were made of total thyroid volume and serum concentrations of TSH at baseline and after 6 months of follow-up. RESULTS: Of the 46 patients, 13 were excluded from the study, as they were unable to complete the treatment or left the follow-up process. After 6 months of exenatide treatment, the serum TSH concentration decreased significantly (from 2.3 [0.7-5.4] to 1.8 mIU/L [0.3-4.2], p= 0.007). There were no significant differences in thyroid volume (11.6 ± 9.0 vs. 12.1 ± 8.8 cm3, p = 0.19), free thyroxine (fT4), free tri-iodothyronine (fT3), and calcitonin levels before and after treatment. Thyroid volume was not affected by decreased TSH level (p:= 0.141) or a reduction in body mass index (BMI) (p > 0.05), and no correlation was detected between variation in TSH level and change in BMI (p > 0.05). CONCLUSIONS: Exenatide treatment for 6 months significantly decreased serum TSH concentration but did not affect thyroid volume in diabetic patients without thyroid disease.
ABSTRACT
OBJECTIVE: Nonfunctioning pituitary adenoma (NFPA) accounts for 30% of all pituitary adenomas, and its incidence has been increasing compared to previous years. Increased risk of cardiovascular effects shown in recent studies is noteworthy in patients with NFPA diagnosis, but the number of studies on the subject is limited. In this study, we aimed to assess possible cardiovascular effects and risk via arterial stiffness measurements in patients diagnosed with NFPA. METHODS: We performed arterial stiffness measurements for 30 patients diagnosed with NFPA and 30 healthy volunteers and compared the results to explore the relationship between arterial stiffness parameters, hormone levels, and adenoma size. RESULTS: Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), central SBP, central DBP, augmentation index corrected for a heart rate of 75 beats per minute (AIx@75), and pulse wave velocity (PWV) values of the patients with NFPA diagnosis were significantly higher than the control group. PWV was found to have a significant and negative correlation with growth hormone and insulin-like growth factor 1 (IGF-1). A significant and positive correlation was found between adenoma median short-axis length and PWV. IGF-1 was found to have a significant and negative correlation with adenoma median long- and short-axis length. In multivariate linear regression analysis, we found that IGF-1 was an independent predictor of PWV. CONCLUSION: Both arterial stiffness parameters such as AIx@75 and PWV and peripheral SBP, DBP, and MBP values were found to be high in NFPA patients with no cardiovascular risk factors. Our findings suggest increased cardiovascular effect and risk in patients with NFPA diagnosis, and therefore, we recommend that patients are monitored closely in this respect. ABBREVIATIONS: ACTH = adrenocorticotropic hormone; AIx@75 = augmentation index corrected for a heart rate of 75 beats per minute; BMI = body mass index; CVD = cardiovascular disease; DBP = diastolic blood pressure; FSH = follicle-stimulating hormone; GH = growth hormone; HT = hypertension; IGF-1 = insulin-like growth factor 1; LH = luteinizing hormone; MBP = mean blood pressure; MRI = magnetic resonance imaging; NFPA = nonfunctioning pituitary adenoma; PP = pulse pressure; PWA = pulse wave analysis; PWV = pulse wave velocity; SBP = systolic blood pressure; TSH = thyroid-stimulating hormone.