Expression of a dominant-negative mutant human insulin receptor in the muscle of transgenic mice.

To examine the in vivo effects of a kinase-deficient mutant human insulin receptor, we used the muscle creatine kinase promoter to express a putative dominant-negative receptor: Ala1134-->Thr (Moller, D. E., Yokota, A., White, M. F., Pazianos, A. G., and Flier, J. S. (1990) J. Biol. Chem. 265, 14979-14985) in transgenic mice. Two lines were generated, where receptor expression was restricted to striated muscle and was increased by 5-12-fold in skeletal muscle. Transgenic gluteal muscle insulin receptor kinase activity was reduced by approximately 80% after maximal in vitro insulin stimulation. Glycogen content in this muscle was reduced by 45% in transgenic mice. Insulin levels were approximately 2-fold higher, and glucose concentrations were 12% higher in transgenics fed ad libitum. Transgenic mice exhibited reduced in vivo sensitivity to low dose (0.1 milliunits/g) intravenous insulin. In isolated soleus muscles from transgenics, where mutant receptors were expressed at lower levels, insulin-stimulated receptor kinase activity was reduced by 42%, but insulin-stimulated 2-deoxyglucose uptake was unaffected. These results indicate that (i) overexpression of a kinase-deficient human insulin receptor in muscle causes dominant-negative effects at the level of receptor kinase activation, (ii) impairment of insulin-stimulated muscle receptor tyrosine kinase activity can cause decreased insulin sensitivity in vivo, (iii) kinase-defective receptor mutants may be used to create novel animal models of tissue-specific insulin resistance.