Progressive suppression of muscle glucose utilization during pregnancy.

Glucose utilization indices (GUIs) were measured in heart and a range of skeletal muscles in conscious, unrestrained, virgin or pregnant rats in the absorptive and post-absorptive phases. A clear effect of pregnancy to diminish muscle GUIs was identified, the magnitude of which was greatest in late gestation in the absorptive phase. Differences in the time courses and magnitudes of the response to pregnancy were observed between individual muscles. The effects of pregnancy are discussed in relation to an increased availability of lipid fuels and to decreased insulin and glucose concentrations.