Increased uncoupling protein-2 and -3 gene expressions in skeletal muscle of STZ-induced diabetic rats

(STZ)-induced diabetic animals are vulnerable to cold stress, Uncoupling pr oteins (UCPs) play an important role in regulating thermogenesis, We invest igated the gene expressions of UCPs in brown adipose tissue (BAT), white ad ipose tissue (WAT), liver and gastrocnemius muscle of STZ-diabetic rats usi ng Northern blot, UCP-1, -2 and -3 mRNA expressions in BAT sere all remarka bly lower in STZ-diabetic rats than those in control rats. Both UCP-2 and - 3 gene expressions in gastrocnemius muscle were substantially elevated in S TZ-diabetic rats and insulin treatment restored UCP gene expressions to nor mal levels. These results suggest that in STZ-diabetic rats, the overexpres sion of UCP-2 and UCP-3 in skeletal muscle provides a defense against hypot hermogenesis caused by decreased UCPs in BAT. (C) 1998 Federation of Europe an Biochemical Societies.