Meeting Abstract
During development, mammals and birds go through a remarkable developmental change from an ectothermic to endothermic phenotype. Although well documented, the regulation of this transition to endothermy is not as well understood. In hatching chickens , there is an increase in circulating plasma thyroid hormones triiodothyronine (T3) and thyroxine (T4) that correlates with the developmental increase in metabolic capacity that may be responsible for the enhanced ability to respond to a cold challenge. Our lab has investigated developmental time periods, morphology, and mitochondrial responses during this transition and is now exploring changes in membrane lipidomics. The membrane pacemaker hypothesis proposes that increased levels of docosahexaenoic acid (DHA) in the membrane are associated with increased metabolic rate. Thus, increases in basal metabolic rate associated with hatching and attainment of endothermy may be driven in part by changes in DHA levels. Here we investigate how manipulations of plasma T3 concentrations affect membrane lipid levels in cardiac and hepatic tissues during this transition to ex ovo life. Embryos were given supplemental T3 or methimazole, a thyroperoxidase inhibitor on day 17 of incubation, and changes in docosahexaenoic acid and linoleic acids were measured during and after hatching. Our novel experiment provides a more thorough understanding of the cellular changes associated with the ontogeny of endothermy and potential membrane effects on metabolism.
