The effect of maternal hypothyroidism during pregnancy on carbohydrate metabolism in adulthood in rats

Introduction: Many of the diseases of adulthood are originated from the intrauterine conditions during fetal life. Because of the importance of thyroid hormones in growth and development of the fetus, the effects of maternal hypothyroidism on carbohydrate metabolism in adulthood was investigated. Methods: Pregnant rats were divided into the fetal hypothyroidism (FH) and the control (C) groups. During the gestational period, propylthiouracil (PTU) dissolved in drinking water (100 ppm) was administered to the FH group, while the C group drank tap water. After delivery and maturation of male neonates, intravenous glucose tolerance test (IVGTT) was performed. For IVGTT tests, catheters were inserted into the femoral vein and artery after anesthesia. The first arterial sample was taken before injections, then the glucose solution was injected and other samples were obtained after 5, 10, 15, 20, 30 and 60 minutes. Plasma glucose and insulin concentrations were measured using the glucose oxidase and an ELISA method, respectively. Results: Plasma glucose concentration 5 min after glucose injection in the FH group (239.2 ± 15.6 mg/dL) was significantly higher than the C group (190.1 ± 4.5 mg/dL, P<0.05). There was no significant difference in plasma insulin concentrations of the 2 groups. Daily water consumption during the gestation in PTU administered mothers was significantly lower compared to the C group (P<0.05). The body weight of animals was significantly (P<0.05) lower in the FH group compared with the C group. Conclusion: Maternal hypothyroidism can alter carbohydrate metabolism during adulthood, which may contribute to the development of diabetes.