Study The Relationship Between Salt Sensitivity And Renin-Angiotensin-Aldosterone Change In Type 2 Diabetes Mellitus With Hypertension

Objective To obtain the ratio of salt sensitivity and investigate the relationship between salt sensitivity and renin-angiotensin-aldosterone change in type 2 diabetes mellitus (T2DM) and T2DM with hypertension, the inpatients were given acute oral normal saline test and the activity of renin, the concentration of angiotensin and aldosterone were measured before and after the saline trial.Methods Thirty-three healthy people were elected as normal control. Sixty-six inpatients were divided into the group of T2DM, the group of T2DM with hypertension. The two groups were further separated into the group of the salt-sensitiveness and the group of the non salt-sensitiveness by acute oral normal saline test. The blood pressures were taken, the blood samples were taken, the activity of rennin was counted, and the blood concentration of angiotensin and aldosterone were measured, before and after the acute oral normal saline test in each group.Results (1) 15 inpatients were sensitive to salt in the group of T2DM (n=30), salt-sensitiveness percentage is 50%; 20 inpatients were sensitive to salt in the group of T2DM with hypertension (n=36) salt-sensitiveness 55.6%. (2) Whether T2DM or T2DM with hyperten-sion, the mean arterial pressure (MAP) in the groups of the salt-sensitive-ness increased markedly after acute oral normal saline test, and decreased after furosemide was taken; The MAP in the groups of the non salt-sensitiveness had no obvious changes whether after acute oral normal saline test or furosemide taken. (3) Before drinking saline, the activity of renin and the blood concentration of aldosterone in the group of the salt-sensitiveness was lower than in the group of the non salt-sensitiveness, no matter whether they were T2DM or T2DM with hypertension; The activity of renin and the blood concentration of aldosterone in all of the diabetic inpatients were lower than normal control (P<0.05) no matter whether they were sensitive or non sensitive to salt. In the group of the salt-sensitiveness, the activity of renin and the blood concentration of aldosterone in the group of T2DM with hypertension were lower than in the group of T2DM. (4) After drinking saline, in the group of T2DM, the activity of rennin, the blood concentration of angiotensin I (37℃) and aldosterone of those sensitive to salt were increased, of those non sensitive to salt were decreased. In the group of T2DM with hypertension, the activity of rennin and the blood concentration of angiotensin I and aldosterone in the group of the salt-sensitiveness increased, and the activity of rennin and the blood concentration of aldosterone increased significantly (P<0.05), but all in the group of the non salt-sensitiveness decreased. (5) In sensitive to salt, the activity of renin and the blood concentration of aldosterone in the group of T2DM with hypertension were higher than in the group of T2DM after drinking saline.Conclusions About half of all in both groups of T2DM and T2DM with hypertension were sensitiveness of salt. In T2DM with hypertension, limiting the salt-intake and using diuretic may control the hypertension helpfully for those sensitive to salt. Among the two diabetic groups, the activity of renin and the blood concentration of aldosterone in those of sensitive to salt were lower than that in those of non sensitive to salt. After drinking saline, it increased in all groups of salt-sensitiveness, and decreased in all groups of non salt-sensitiveness. In the groups of the salt sensitiveness, the reactive of renin-angiotensin-aldosterone system in T2DM with hypertension increased markedly than in T2DM after drinking saline.