We investigated whether specific lipoprotein abnormalities are present in non-insulin-dependent diabetes mellitus (NIDDM) patients with hypertension and/or microalbuminuria. Fifteen normotensive normoalbuminuric (H-M-), 32 hypertensive normoalbuminuric (H+M-), and 22 hypertensive microalbuminuric (H+M+) NIDDM patients and 20 sex-, age-, and weight-matched nondiabetic control subjects were studied. Lipoprotein size was measured by nondenaturing polyacrylamide gradient gel electrophoresis; insulin sensitivity was assessed by using a euglycemic hyperinsulinemic clamp and [6,6(2)H]glucose tracer infusion for simultaneous measurement of hepatic glucose output and whole-body glucose utilization. Total plasma and very-low-density lipoprotein cholesterol were higher in H+M+ than in control subjects (5.84 +/- 0.98 versus 4.97 +/- 0.98 and 0.57 +/- 0.54 versus 0.26 +/- 0.21 mmol/L, mean +/- SD, P < .05). Plasma triglycerides were higher in H+M+ than in either control or H-M- subjects (2.17 +/- 1.32 versus 1.18 +/- 0.67 and 1.30 +/- 0.59 mmol/L, respectively; P < .05). The mean low-density lipoprotein diameter was 27.2 +/- 0.8 in control, 26.7 +/- 0.8 in H-M-, 26.5 +/- 0.8 nm in H+M- (P < .05 versus control subjects), and 26.0 +/- 0.8 nm in H+M+ subjects (P < .05 versus control subjects). The mean cholesterol level of the large high-density lipoprotein particles was lower in H+M- and H+M+ (0.37 +/- 0.14 and 0.36 +/- 0.16 mmol/L) than in control and H-M- (0.54 +/- 0.41 and 0.54 +/- 0.27 mmol/L, P < .05) subjects.(ABSTRACT TRUNCATED AT 250 WORDS)