Meeting Abstract

125.5  Monday, Jan. 7  Metabolic signals differentially regulate trade-offs between the reproductive and immune systems in female Siberian hamsters CARLTON, E.D.*; COOPER, C.L.; DEMAS, G.E.; Indiana Univ., Bloomington; Claflin Univ., Orangeburg, SC; Indiana Univ., Bloomington elcarlto@indiana.edu

Most free-living animals have finite energy stores that they must allocate to different physiological processes. As such, when energy is limited, energetic trade-offs among these physiological systems may occur. In our study, we experimentally limited energy availability to female Siberian hamsters (Phodopus sungorus) with 2-Deoxy-D-glucose (2-DG), a non-metabolizable glucose analog that disrupts cellular utilization of glucose. We observed how treatment with a low or high dose of 2-DG affected energy allocation to the reproductive and immune systems. We predicted that limiting energy availability via 2-DG treatment would decrease reproductive and immune functions. In addition, a subset of hamsters was treated with leptin, an adipose hormone that provides a direct signal of available fat stores. We predicted that leptin treatment would provide a “false signal” of energy reserves and would reduce the energetic constraints imposed by 2-DG. We found that 2 -DG treatment reduced, but leptin did not restore, reproductive tissue mass. Additionally, leptin treatment enhanced innate immunity, as measured by a bacterial killing assay, although 2-DG treatment had no effect on this measure. In contrast, the high dose of 2-DG decreased immunoglobulin G (IgG) production in response to a foreign antigen; however, leptin treatment did not counteract the 2-DG induced decrease in IgG levels. Rather, leptin appeared to enhance the negative effects of 2-DG on IgG levels. Collectively, these findings suggest that an animal’s current energy balance can affect both reproductive and immune responses but that different metabolic fuels affect energy allocation to the reproductive and immune systems in dissimilar ways.