This obesity model has altered circulating insulin (Yang et al., 2012), alterations to steroidogenesis (Nteeba et al., 2014b), decreased number of primordial follicles from 12 weeks of age onwards (Ganesan et al., 2017), and a diminished response to environmental toxicants (Ganesan et al., 2014, 2017; González-Alvarez et al., 2021). This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.