BECN1 and Glucose intolerance: Interestingly, despite their glucose intolerance in GTT, homozygous Becn1FA/FA or heterozygous Becn1FA/+ mice had an elevated insulin response in the ITT compared to WT mice; this phenomenon is different from that of the autophagy-deficient Becn1+/− KO mice, which are not only more glucose intolerant but also more insulin resistant than WT mice (Figure 2B).