Local cerebral glucose utilization in the adult cretinous rat.

Local rates of cerebral glucose utilization were determined in 5-month-old neonatally radiothyroidectomized and control (littermate) rats. Virtually all 48 brain regions examined in the thyroidectomized rats exhibited lower rates of glucose utilization than those of the controls with differences ranging from -24 to -58%. The decreases were particularly large in the cerebral cortex and throughout the auditory system. Altered patterns in the intrastructural distribution of rates of glucose utilization were seen in a number of regions and were particularly prominent in the hippocampus and inferior colliculus. Lesser changes were seen in hypothalamic regions involved in the synthesis of thyrotropin releasing hormone (TRH). The results indicate that the many structural, functional and biochemical abnormalities of cretinism are associated with widespread reductions in energy metabolism throughout the brain.