부산대학교 도서관

The ability of metabolically active tissues to increase glucose uptake in response to insulin is critical to whole-body glucose homeostasis. This report describes the Dual Tracer Test, a robust method involving sequential retro-orbital injection of [14C]2-deoxyglucose ([14C]2DG) alone, followed 40 min later by injection of [3H]2DG with a maximal dose of insulin to quantify both basal and insulin-stimulated 2DG uptake in the same mouse. The collection of both basal and insulin-stimulated measures from a single animal is imperative for generating high-quality data since differences in insulin action may be misinterpreted mechanistically if basal glucose uptake is not accounted for. The approach was validated in a classic diet-induced model of insulin resistance and a novel transgenic mouse with reduced GLUT4 expression that, despite ubiquitous peripheral insulin resistance, did not exhibit fasting hyperinsulinemia. This suggests that reduced insulin-stimulated glucose disposal is not a primary contributor to chronic hyperinsulinemia. The Dual Tracer Test offers a technically simple assay that enables the study of insulin action in many tissues simultaneously. By administering two tracers and accounting for both basal and insulin-stimulated glucose transport, this assay halves the required sample size for studies in inbred mice and demonstrates increased statistical power to detect insulin resistance, relative to other established approaches, using a single tracer. The Dual Tracer Test is a valuable addition to the metabolic phenotyping toolbox. Article Highlights: A need exists for technically simple and reproducible assays for measuring insulin action in vivo across many tissues simultaneously. The Dual Tracer Test is a robust in vivo technique to obtain basal and insulin-stimulated glucose uptake measures from the same mouse and halves the number of mice required for studies in inbred mice. Minimum data reporting standards are provided to assist future users of the Dual Tracer Test to critically interpret experiments and results and to reduce the potential for technical drift. Partial knockdown of GLUT4-generated ubiquitous peripheral insulin resistance and glucose intolerance in the absence of hyperinsulinemia suggests that fasting hyperinsulinemia is not a primary consequence of reduced insulin-stimulated glucose disposal. [ABSTRACT FROM AUTHOR]