The Effect of Maternal Hypothyroidism on the Carbohydrate Metabolism and Insulin Secretion of Isolated Islets in Adult Male Offspring of Rats

Thyroid hormones have crucial developmental effect during fetal life. This study investigates the effects of maternal hypothyroidism on the carbohydrate metabolism and insulin secretion capacity of islets of the adult male offspring of rats. One group of pregnant mothers (fetal hypothyroid) of Wistar rats drank water containing 0.02% of 6-propyl-2-thiouracil during pregnancy, while the control group consumed only tap water. After delivery, survival and weight of the neonates from both groups were followed. In adult male offspring, the intravenous glucose tolerance test was performed and 5-6 weeks later, glucose-stimulated insulin secretion of isolated islets was assessed. Plasma glucose concentration of the fetal hypothyroid group during intravenous glucose tolerance test was significantly higher (p=0.003) at 5-20 min as compared to the control group, whereas plasma insulin concentration was significantly lower (p=0.012) at 5-20 min. Insulin secretion of the isolated islets stimulated with 16 mM glucose of the offspring in the fetal hypothyroid group (376.2 ± 57.1 pmol/islet/60 min) was significantly lower (p=0.02) as compared to the control group (618.1 ± 85.2). Although adult offspring born from hypothyroid mothers were euthyroid, their glucose tolerance and glucose stimulated insulin secretion of islets were altered, which may eventually contribute to the development of diabetes.