Development of the rat hepatic microsomal glucose-6-phosphatase system and its glucocorticoid inducibility.

Rat liver glucose-6-phosphatase activity was determined in both fully activated and intact microsomal preparations during perinatal development. Activities increased rapidly in both preparations following birth, then gradually fell to adult values. The latency of the glucose-6-phosphatase system also increased neonatally whereas hepatic glycogen concentrations decreased postnatally. The effect of dexamethasone pretreatment on the hepatic glucose-6-phosphatase system was also investigated. Dexamethasone pretreatment failed to decrease the latency of glucose-6-phosphatase in microsomes from neonatal rats but decreased the latency of the enzyme in adult female rat liver from 44 to 12% of total activity.