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.