Exposure to Uteroplacental Insufficiency Reduces the Expression of Signal Transducer and Activator of Transcription 3 and Proopiomelanocortin in the Hypothalamus of Newborn Rats

IUGR has been linked to the development of type 2 diabetes. Recent data suggest that some of the molecular defects underlying type 2 diabetes reside in the CNS. Disruption of the signal transducer and activator of transcription 3 (STAT3) in the hypothalamic neurons expressing leptin receptor, results in severe obesity, hyperglycaemia, and hyperinsulinemia. Our aim was to investigate the expression of STAT3 and its downstream effector proopiomelanocortin (POMC) in IUGR rats obtained by uterine artery ligation. On day 19 of gestation, time-dated Sprague-Dawley pregnant rats were anesthetized, and both the uterine arteries were ligated. At birth, hypothalamus was dissected and processed to evaluate the expression of STAT3, its phosphorylated form, and POMC. STAT3 mRNA, STAT3 protein, phosphorylated STAT3, POW mRNA, and POMC protein were significantly reduced in IUGR versus sham animals (p < 0.0001. p < 0.05 and p < 0.001, p < 0.01, p < 0.01 respectively). No significant differences either in serum leptin concentrations or in hypothalamic leptin receptor expression were observed. Our results suggest that an abnormal intrauterine milieu call affect the hypothalamic expression of STAT3 and POW at birth. altering the hypothalamic signaling pathways that regulate the energy homeostasis. (Pediatr Res 66: 208-211, 2009)