Blood and plasma glucose relationships during pregnancy, the breeding cycle and development in the rat

The concentration of blood and plasma glucose in developing, pregnant and post-partum rats has been determined under uniform conditions of housing, feeding and circadian rhythms. The glucose content of erythrocytes and of the plasma compartment has been estimated using the packed cell hematocrit value as correction factor. During pregnancy and fetal development there were significant reductions in the proportion of intracellular glucose, and significant increases during the suckling and weaning period. There was no direct relationship with plasma insulin levels. Results are discussed in relation to aspects of metabolism specific to the physiological components of the breeding cycle studied; plasma glucose homeostasis is held very constant; both intraerythrocytic and plasma concentrations should be considered when studying glucose homeostasis in given physiological situations.