The purpose of this study is: 1) To study the associations among hypertension, insulin resistance and the renal modulation status and their genetic determinants; 2) to determine the effect of Lisinopril (an ACE inhibitor) on insulin resistance, cardiovascular risk factors, and renal modulation; 3) to examine the hypothesis that the reponse to ACE inhibitors may be genetically determined in sibling pairs at risk for the development of NIDDM.