Effects of neonatal hypothyroidism on the expressions of growth cone proteins and axon guidance molecules related genes in the hippocampus

During critical periods of development, hypothyroidism causes abnormalities of the central nervous system such as incomplete maturation of neuronal an d glial cells. reduction in synaptic densities and myelin deficits. In this study expression of development regulated genes, ie transcription of beta -actin, sema 3F, CRMP I to 4. GAP-43, G alpha o1, G alpha o2 and translatio n of beta -actin, G alphao, G alpha o1, CRMP-2, CRMP-4 genes were examined in the hippocampus of neonatal methimazole induced hypothyroid rats at the age of day 16. All CRMPs mRNA levels were significantly higher in the hypot hyroid rats. Significant higher CRMP-2 protein but not CRMP-4 protein was f ound in the hypothyroid rats. The neonatal experimental hypothyroid states did not affect the protein levels of beta -actin but up-regulate its mRNA. Transcription of CRMP I to 4, GAP-43, Gaol but not Gao2 and sema 3F was alt ered by the neonatal treatment. The only sex difference in gene expression was found in the transcription of CRMP-2 gene. (C) 2001 Elsevier Science Ir eland Ltd. All rights reserved.