Effect of Fetal and Neonatal Hypothyroidism on Glucose Tolerance in Middle- Aged Female Rats

Background and Objective: The effects of hypothyroidism during pregnancy and lactation on carbohydrate metabolism have been mostly studied in male animals. The aim of this study is, therefore, to investigate the effect of fetal and neonatal hypothyroidism (FH and NH) on glucose tolerance in middle-aged female rat offsprings. Methods: Pregnant female rats were divided into three groups: Rats in the control group consumed tap water, while those in the FH and NH groups consumed 250 mg/L of 6-propyl-2-thiouracil (PTU) in their drinking water during gestation or lactation periods, respectively. After weaning, the female offspring were separated and divided into 3 groups (n=8/group): Control, FH, and NH. Bodyweight was recorded monthly and an intravenous glucose tolerance test (IVGTT) was performed at month 12. Results: Compared to controls, female rats in the FH group had significantly higher plasma glucose levels than controls throughout the IVGTT except at min 60. Values at min 5 of the FH and control group were 196.1±1.9 and 155.3±5.9 mg/dL, respectively (P<0.05). In the NH group, plasma glucose levels were significantly higher only at min 5 (185.7±14.1 vs. 155.3±5.9 mg/dL, P<0.05). Conclusion: Hypothyroidism during fetal or neonatal periods caused glucose intolerance in middle- aged female offspring rats.