OBJECTIVE The present study was done to observe the insulin secretory response in healthy adult offspring of normotensive and hypertensive parents as the etiology of essential hypertension is largely treated as unknown. METHODS The insulin secretary response was observed in 20 healthy adult offspring of normotensive parents (Group I) and 25 healthy adult offspring of hypertensive parents (Group II). The mean serum insulin levels were assessed at fasting, 30, 60, 90 and 120 minutes after 75 grams of oral glucose load in both groups. RESULTS The mean serum insulin levels in fasting state was higher in group II (32.40 +/- 18.59) than group I (17.90 +/- 11.98) (p < 0.01). After 30 minutes mean serum insulin levels were higher in group II than group I (88.00 +/- 56.04, 40.5 +/- 15.15 respectively, p < 0.001). There was no statistically significant difference after 60, 90 and 120 minutes of oral glucose load (p > 0.05). CONCLUSIONS Our observations suggest that the insulin secretory response in fasting and 30 minutes after oral glucose load was earliest metabolic abnormality in subjects at high risk for developing hypertension i.e. offspring of hypertensive parents.