RESUMEN
The goal of this study is to investigate whether congenital hypothyroidism induced by MMI during gestation (G) or gestation plus lactation (GL) would affect the leptin action upon body weight control on hypothalamus. Six to eight pups per group were killed at 90 days of age. For statistical analysis one-way ANOVA followed by the Holm-Sìdak post hoc test was used. Hypothyroidism resulted in a significant increase in leptin serum levels in G 20% and GL 25% (p<0.04). There was a significant expression decrease of OBR in G 45% and GL 63%; pSTAT3 in G 56% and GL 51%; pERK in G 50% and GL 48%; POMC in G 41% and GL 46% (p<0.04), while a significant increase was assigned to SOCS3 in G 52% and GL 170% (p<0.04) protein expression. We can conclude that hypothyroxinemia condition in rats on adulthood results in impairment of the leptin signaling pathway via ObRb-STAT3 in the hypothalamus, which is likely to be involved in the leptin resistance.