Changes of Blood Pressure and its Relation with Plasma Glucose and Insulin Concentration During Oral Glucose Tolerance Test in Patients with Essential Hypertension

The blood pressure (BP), heart rate (HR), plasma glucose (G) and insulin (I) concentration and their relation with each other during oral glucose tolerance test (OGTT) were studied in 54 patients aged 32-79 (mean 56.4±10) with essential hypertension and in 21 normal subjects aged 31-70 (mean 51.7±12.6). After a 2-week washout period without therapy, BP and HR were recorded in supine position. Blood samples were taken for G and I concentration. THen OGTT lasting 4 hours was performed with 75 g glucose. Blood samples for I were taken at first and third hour of OGTT and for G at every hour. BP and HR were recorded at every 30 minutes. Systolic (SBP) and diastolic blood pressures (DBP) during OGTT significantly declined in hypertensive patients. There was no significant change in HR. BP and HR did not change significantly in normal subjects. The patients were evaluated in five age groups between ages 30 to 80, comprising 4,12,14,18 and 6 patients, respectively. The blood pressure decreased slightly in all groups during oral GTT. But the significant reduction in SBP was seen only in sixth and seventh decades while the DBP declined in the fifth, sixth and seventh decades. In these groups there was no significant difference between I and G concentrations during OGTT. It is concluded that the reduction of BP in hypertensive patients after OGTT might be related to some factors associated with plasma glucose concentration.