Plasma glucose and insulin responses to oral glucose loading in nonobese Nigerian subjects with essential hypertension.

In assessing the relationship between insulin levels and blood pressure, we analyzed glucose and insulin data after standard 75 g oral glucose tolerance tests in 16 nonobese male Nigerian subjects with essential hypertension and compared their results with those obtained from 16 age- and sex-matched healthy normotensive subjects. The fasting plasma glucose and insulin as well as 2-hour postload insulin values were similar in both groups. The hypertensive subjects had significantly greater 2-hour glucose levels, larger incremental areas under the glucose/time curves, and smaller ratios of incremental insulin to incremental glucose areas (P < .05). These parameters suggest some impairment of glucose tolerance in the hypertensive subjects related to an inadequate insulin response to the oral glucose load. Model analysis of the glucose and insulin data confirmed these observations in that the estimated rate of glucose uptake into peripheral tissues (M value) was lower in the hypertensive subjects (P = .02). There was no correlation at any time point between insulin values and blood pressure in either group of subjects. These results suggest that essential hypertension in Nigerian diabetic subjects is associated with a reduced insulin response to glucose loading, which is at variance with reports in whites, and deserve further investigation.