OGG1 and obesity due to melanocortin 4 receptor deficiency: Considering that lack of OGG1 contributes to obesity and metabolic dysfunction in mice, we were interested in (1) determining tissue-specific insulin resistance in Ogg1−/− (Ogg1-KO) mice; and (2) evaluating the contribution of mt-hOGG1 alone to whole-body insulin resistance in mice.