Finally, the resistance to IGF-1 in CKDis also caused by the defect in intracellular sig-nal transduction as both: the autophosphorylationof the IGF-1 receptor tyrosine kinase and sus-ceptibility of the IGF-1R tyrosine kinase to theexogenous insulin receptor substrate-1 (IRS-1) are diminished in CKD [8, 9, 11, 12].