NaCl sensitivity of essential hypertensive patients is related to insulin resistance.
OBJECTIVE
To evaluate insulin sensitivity of essential hypertensive patients with different salt sensitivities of blood pressure in the absence of confounding factors such as obesity, glucose intolerance and the inclusion both of normotensive and of hypertensive subjects that have affected most previous studies.


METHODS
Ninety-nine patients with untreated mild or moderate essential hypertension, World Health Organization class I-II, participated in the study.


METHODS
Salt sensitivity was estimated using the Weinberger protocol with minor modifications and the patients were classified into tertiles of salt sensitivity.


RESULTS
Patients with high NaCl sensitivities were slightly older and had somewhat higher blood pressures than did subjects with low salt sensitivities. Plasma renin activity significantly decreased with increasing salt sensitivity. There were no differences among the three groups in terms of body mass index, fasting blood glucose and insulin plasma levels. There were no differences among the groups in the integrated glucose and insulin response to a standard oral-glucose tolerance test However, there was a significant difference in insulin sensitivity between two subgroups of the upper and lower tertile of salt sensitivity, the salt-sensitive hypertensives having a markedly lower utilization of glucose than did the salt-resistant ones, with a minor overlap (5.4 +/- 0.6 versus 7.4 +/- 0.3 mg/kg per min, P < 0.01).


CONCLUSIONS
This study showed that essential hypertensive patients with high NaCl sensitivities were relatively insulin resistant compared with those with low NaCl sensitivities, independently of confounding factors such as age, obesity and glucose intolerance. Insulin resistance was not associated with overt hyperinsulinaemia among these patients.
Galletti
F
F
Department of Clinical and Experimental Medicine, Medical School, Federico II University of Naples, Italy.
Strazzullo
P
P
Ferrara
I
I
Annuzzi
G
G
Rivellese
A A
AA
Gatto
S
S
Mancini
M
M
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D004351:Drug Resistance; D005260:Female; D015309:Glucose Clamp Technique; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000503:physiopathology*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012083:Renin / Q000097:blood; D012965:Sodium Chloride / Q000494:pharmacology*
D012965:Sodium Chloride; D012083:Renin