SLC2A4 and obesity due to melanocortin 4 receptor deficiency: What is more, Robker and others (Robker et al., 2009), that obesity phenotype of granulosa and cumulus cells correlated with increased insulin levels and suppressed SHBG expression in combination to lower Glut-4 and IRS2 transcript abundance, evoking an IRS1/IRS2 axis deactivation and a resulting insulin resistance status.