High plasma amylin/islet amyloid polypeptide levels in patients with residual medullary thyroid carcinoma after total thyroidectomy

Objective: We have previously reported that amylin/islet amyloid polypeptide (IAPP) mRNA is detected in a substantial subset of medullary carcinomas of the thyroid (MTCs). The aim of this study was to determine if the amylin/IAPP gene is expressed as the IAPP peptide in MTC tissues. Design and Methods: In 10 patients with a histological diagnosis of MTC and with persisting or recurrent disease (basal calcitonin levels > 250 pg/ml), the fasting serum insulin and plasma glucose, IAPP and calcitonin levels were measured and compared with those of 18 normal control subjects matched for age and body mass index. IAPP expression was studied by immunohistochemistry in MTCs and lymph-node metastasis tissues. Results: Seven of ten MTC patients had abnormally elevated IAPP levels. Plasma IAPP and serum insulin levels were correlated in both patients and controls, but the slope of the regression line was significantly higher for MTC patients. IAPP staining was detected in four out of 12 random MTC samples and in two out of five lymph-node metastases, using immunohistochemistry. Conclusions: These results indicate that MTC cells express IAPP at the peptide level and that this raises the peripheral plasma levels. Further studies may reveal whether this is a feature of malignant disease

Study of the Trp(64)Arg Polymorphism of the beta(3)-adrenergic receptor in Greek women with gestational diabetes

OBJECTIVE - This study assessed whether the Trp(64)Arg polymorphism of the beta(3)-adrenergic receptor (beta(3)-AR), which has been associated with obesity, insulin resistance, weight gain, and earlier onset of type 2 diabetes, is more frequent in women who develop gestational diabetes mellitus (GDM) or whether it is associated with weight gain during pregnancy. RESEARCH DESIGN AND METHODS - A total of 311 Greek pregnant women (180 with GDM and 131 without GDM [control]) who underwent a 100-g oral glucose tolerance test (OGTT) in the third trimester of pregnancy were genotyped for the beta(3)-AR Arg(64) polymorphism. Insulin levels were also determined during the OGTT. RESULTS - The frequency of Trp(64)Arg heterozygotes in this population was similar to 7% and was similar in the GDM and control groups (6.7 vs. 6.9%) as well as in the obese (BMI greater than or equal to 27 kg/m(2)) and the nonobese (6.3 vs. 6.8%) subgroups. In the GDM group, BMI, fasting insulin resistance index, and diastolic blood pressure were significantly higher in Trp(64)Arg carriers; these differences were no longer observed when obesity was considered. In the 4 subgroups (control Trp(64)Trp and Trp(64)Arg and GDM Trp(64)Trp and Trp(64)Arg), a highly significant trend was evident of an increase in the percentage of subjects with shorter height. CONCLUSIONS - The frequency of the Arg(64) allele in Greek pregnant women is relatively rare compared with other ethnic groups and is probably not related to the development of GDM or obesity. The observed tendency for shorter body height in Arg(64) carriers merits further evaluation in larger population samples