INSULIN-RESISTANCE IN ESSENTIAL HYPERTENSIVE PATIENTS WITH IMPAIRED GLUCOSE-TOLERANCE

This study evaluated insulin secretion and insulin sensitivity in 17 n on-obese hypertensive patients (aged 45.6 +/- 2.2 years, body mass ind ex 24.0 +/- 0.5 kg/m(2), mean +/- S.E.M.) with (n = 8) and without glu cose intolerance (n = 9) and compared the results with those of 16 age -matched non-obese normotensive subjects with (n = 7) and without gluc ose intolerance (n = 9), The hypertensive patients without glucose int olerance showed a significantly lower insulin-mediated glucose disposa l and a compensating increase in second-phase insulin secretion compar ed with normotensives without glucose intolerance, In hypertensives wi th glucose intolerance, insulin-mediated glucose disposal was signific antly lower and second-phase insulin secretion was comparable to that in normotensives without glucose intolerance, After 3 months of angiot ensin-converting enzyme (ACE) inhibition with oral administration of d elapril, blood pressure was significantly reduced in the hypertensives with glucose intolerance (n = 9). The insulin-mediated glucose dispos al significantly (P < 0.01) recovered from 6.0 +/- 0.81 to 8.0 +/- 0.7 1 mg/kg per min. The second-phase insulin secretion tended to be lower (but not significantly) but insulin clearance increased from 15.4 +/- 0.85 to 19.1 +/- 1.42 ml/min (P < 0.05). These data show that in hype rtensive patients without glucose intolerance insulin resistance might compensatorily augment second-phase insulin secretion and lead to hyp erinsulinemia. In hypertensives with glucose intolerance, insulin resi stance might induce postprandial hyperglycemia, which leads to hyperin sulinemia because of second phase insulin secretion at a level similar to that of normotensives.