[The relationship between insulin resistance and abnormalities of cellular calcium metabolism and cell membrane abnormalities in patients with essential hypertension].

OBJECTIVE

To investigate the relationship between the insulin resistance (IR) and the abnormalities of cellular calcium metabolism and cell membrane in patients with essential hypertension.

METHODS

Plasma insulin and glucose before and during OGTT, membrane ATPase activity, cholesterol (C) and phospholipid (P), lipid peroxides (MDA), intracellular total calcium concentration [(Ca2+)i] and calcium binding capacity of inner surface of membranes were determined in 26 normotensive (NT) subjects, 17 hypertensives (HT), and 16 hypertensives associated with IR (HT + IR).

RESULTS

The HT + IR group had higher levels of plasma glucose and insulin than that in the NT group and HT group with significant differences. The HT + IR group consistently demonstrated depressed activity of each Na(+)-K(+)-ATPase and Ca(2+)-ATPase studied with significant differences when compared with the NT group, but no difference was found if compared with the HT group. There was a higher [(Ca2+)i] in the HT + IR group than those in the NT group and even in the HT group with significant differences, respectively. Insulin sensitivity in the HT + IR group was significantly lower than that in both groups of HT and NT, respectively. The membrane C/P molar ratio and MDA content in the HT + IR group and HT group were significantly higher than those in the NT group, respectively.

CONCLUSIONS

It is likely that there is a causal relation between IR and abnormalities of cellular calcium metabolism and membrane lipids in patients with essential hypertension.