Meeting Abstract
The insulin and insulin-like signaling (IIS) network is an important mediator of growth and metabolism in response to environmental conditions and is conserved across all animal taxa. Although the two main ILS hormones, insulin-like growth factor 1 (IGF-1) and insulin-like growth factor 2 (IGF-2), appear to mediate the trade-off between growth and reproduction, they have been studied primarily in mammals and their individual roles in other taxa, such as reptiles, are only vaguely characterized. Indeed, most studies on IGF have been performed in rodents, which do not express IGF-2 postnatally; and while fluctuations of IGF-1 in response to nutrient availability have received most attention, the responsiveness of IGF-2 to different environmental conditions has never been explicitly tested. We imposed a dietary restriction regime on green anole (Anolis carolinensis) females to test the hypothesis that IGF-1 and IGF-2 expression respond differently to dietary restriction. Specifically, we predicted that IGF-1 expression would be downregulated in diet restricted animals relative to controls, as is the case in other reptiles, whereas IGF-2 expression would be unaffected by dietary restriction. We discuss our results within the greater context of the IIS network as a lynchpin pathway for life-histories, and the potential for differential IGF expression to facilitate adaptive plasticity and maternal effects.
