Figure 1.

Treatment with IR-ASO decreases liver IR protein levels in mice. (A) Protocol of ASO treatment in mice. Mice received i.p. injections of either IR-ASO or control-ASO on days 1 and 4 (7 and 3 days prior to the insulin clamp/insulin signaling studies, respectively). Catheters were inserted in the jugular vein 3 days prior to the clamp studies. (B) IR protein expression in livers of animals treated with IR-ASO or scrambled control-ASO (con-ASO). Livers from mice treated with a low dose (50 mg/kg body weight) of ASO (left panel) or with a high dose (100 mg/kg body weight) of ASO (right panel) were analyzed by Western blot with antiserum against IR. Membranes were stripped and reprobed with antiserum against β-actin for normalization purposes. Note protein dilutions of 1:4 and 1:10 of liver extracts from rats treated with scrambled ASO (last 2 samples on the right) were used for quantification purposes. IR protein is virtually undetectable in IR-ASO–treated mice, whereas a dilution of 1:10 in the control livers still shows a clearly detectable band. Thus, we estimate that the IR protein is downregulated by more than 95% in liver of IR-ASO rats. (C) IR expression in kidney and testis fat. We used the same dilution method as described for B. Samples were derived from the same animals in the same order as for the liver samples in Figure 1B, right panel. (D) Muscle and hypothalamus IR expression were not affected by treatment with IR-ASO.