mice heterozygous for disruption of Gnas exon 1, in which Gsα, but not XLαs, is ablated [41, 82]. In fact, Gnasxl knockout mice demonstrate slightly elevated basal and isoproterenol stimulated cAMP levels in brown adipose tissue at birth [67]. These findings suggest that XLαs has a role distinct from the role of Gsα in mammals, and that it may oppose, at least in certain tissues, the actions of Gsα.
