Imapired Expression of the Uncoupling Protein-3 Gene in Skeletal Muscle During Lactation Fibrates and Trolitazone Reverse Lactation-Induced Downregulation of the Uncoupling Protein-3 Gene

摘要

The expression of uncoupling protein (UCP)-3-mRNA in skeletal muscle is dramatically reduced during lacta- tion in mice. The reduction in UCP-3 mRNA levels low- ers the amount of the Ucp-3 protein in skeletal muscle mitochondria during lactation. Spontaneous or abrupt weaning reverses the downregualtion of the UCP-3 mRNA but not the reduction in UCP-3 protein levels. In lactating and virgin mice, however, fasting increases UCP-3 mRNA levels. Changes in UCP-3 mRNA occur in parallel with modifications in the levels of free fatty acids, which are reduced in lactation and are upregulated due to weaning or fasting.