In a rodent high-fat diet model of obesity, placental Abcb1a mRNA expression was decreased in high-fat-fed pregnant mice compared to placental expression levels in both control and undernourished pregnant mice, whereas placental Abcg2 mRNA expression was increased in high-fat-fed pregnant mice compared to undernourished pregnant mice29. Here, ABCG2 is linked to obesity due to melanocortin 4 receptor deficiency.