STAT3 and hydrops fetalis: However, among three groups of adult male rats born to HF, HP and control dams, only control group displayed an increased phosphorylation level of STAT-3 in the hypothalamus in response to leptin challenge, implying that offspring born to the obese dams brought an early defective leptin signaling, which might account for abnormal striatal DA modulation and consequent impaired adaptive behaviors observed in the former experiments.