Impaired arterial but not venous responsiveness to nitroglycerin in non-insulin-dependent diabetes mellitus.

In earlier studies, the response of the arterioles to nitroglycerin (NTG) was found to be impaired in non-insulin-dependent diabetes mellitus (NIDDM) patients. NTG has major therapeutic effects in reducing cardiac after- and preload. Thus, the vasorelaxing efficacy of a therapeutic dose of 0-4 mg of NTG sublingually (s.l.) was evaluated in the conduit femoral artery and large veins of normotensive, normoalbuminuric NIDDM patients. After NTG, the increase in the femoral artery diameter was significantly lower in the NIDDM patients than in control subjects: 0.49 (0.29-0.79) vs. 0.75 (0.47-1.00) mm respectively (median, interquartile ranges). NTG resulted in an increase of pulse wave transit time in the aorta in control subjects but not in the NIDDM patients: from 64 (60-73) to 70 (63-80) ms, P < 0.02; and from 62 (53-69) to 66 (51-72) ms, P = NS, respectively. The reduction in the venous tone of the forearm to NTG was similar in both groups. These results suggest that the response to NTG is impaired in the arterial system but not in the venous system in well-regulated NIDDM patients without diabetic complications.