Close relationship between microalbuminuria and insulin resistance in essential hypertension and non-insulin dependent diabetes mellitus

Abstract

The aim of this study was to investigate the relationships among insulin resistance and albumin excretion rate in 25 nondiabetic patients with essential hypertension and in 28 patients with non-insulin dependent diabetes mellitus (NIDDM). Two groups of healthy subjects matched for age, sex, and weight served as controls. Patients with essential hypertension were divided into two subgroups: without (H1) and with (H2) microalbuminuria. Diabetic patients were divided into four subgroups: those with normoalbuminuria without (NIDDM1) and with (NIDDM2) hypertension and those with microalbuminuria without (NIDDM3) and with (NIDDM4) hypertension. Wholebody glucose utilization during euglycemic hyperinsulinemic clamp (40 mU/m2/min insulin infusion) was calculated by tracer dilution techniques (6,6 2H2 glucose tracer continuous infusion) and was significantly lower in hypertensives with microalbuminuria than in those without (H2 versus H1 versus controls: 3.41 ± 0.51 versus 6.52 ± 0.62 versus 7.03 ± 0.48 mg/kg/ min; mean ± SE). Whole-body glucose utilization in NIDDM patients - NIDDM4 versus NIDDM3 versus NIDDM2 versus NIDDM1 versus controls - was: 1.86 ± 0.31 versus 2.21 ± 0.39 versus 2.01 ± 0.40 versus 5.98 ± 0.77 versus 5.52 ± 0.92 mg/kg/min (mean ± SE). Whereas the first three subgroups did not differ among themselves, they had significantly lower glucose utilization than did the normotensive NIDDM1 patients without microalbuminuria and nondiabetic controls (P < 0.01). Hypertensives with microalbuminuria had higher Vmax of sodium-lithium countertransport (Na/Li CTT) in red blood cells than did both hypertensives without microalbuminuria and controls. It was also observed that NIDDM patients with microalbuminuria had higher Vmax of Na/Li CTT than did NIDDM patients without microalbuminuria and controls. Both hypertensive and NIDDM patients with microalbuminuria had ultrasound organomegaly at cardiac and renal level and lipid abnormalities. In conclusion, insulin resistance and hypertension are not always associated; however, microalbuminuria is strongly related to insulin resistance and elevated Vmax of Na/Li CTT in essential hypertension as well as in NIDDM.