To investigate whether intracellular MAPK signaling in the hypothalamus of the offspring might be affected by maternal obesity, we determined total protein amount and phosphorylation of the MAP kinases extracellular signal regulated kinases 1/2 (ERK1/2), p38, c-Jun N-terminal kinase 1 (JNK1), and JNK2/3 in the hypothalamus of offspring of obese and lean mouse dams on P21. This evidence concerns the gene MAPK8 and obesity due to melanocortin 4 receptor deficiency.