Basal insulin-level oscillations in normotensive individuals with genetic predisposition to essential hypertension exhibit an irregular pattern.
BACKGROUND
Insulin is secreted in regular pulses at intervals of 12-14 min in normal fasting subjects. An abnormal pattern has been found in subjects with non-insulin-dependent diabetes mellitus (NIDDM) and in young individuals predisposed to NIDDM. It has been suggested that there might be a causal relationship between insulin-secretion abnormalities and insulin resistance.


OBJECTIVE
To examine whether insulin-secretion abnormalities are also present in offspring of patients with essential hypertension.


METHODS
Eleven young (aged 18-35 years) normotensive individuals each of whom had two parents with essential hypertension were compared with 10 age- and sex-matched controls each of whom had two normotensive parents. We verified that diabetes and morbid obesity were absent among the subjects and their parents. We studied basal insulin-secretion patterns during a 60 min period, glucose tolerance by administering an oral glucose-tolerance test, insulin resistance by using an isoglycaemic hyperinsulinaemic clamp and basal plasma catecholamine levels.


RESULTS
Autocorrelation analysis of insulin concentrations showed that the hypertension-prone subjects had a significantly reduced or irregular oscillatory pattern compared with the regular insulin-level oscillations with a period of 12-14 min in control subjects. The hypertension-prone subjects had significantly higher systolic blood pressures and tended to be insulin-resistant.


CONCLUSIONS
This is the first evidence of early insulin-secretion abnormalities in young normotensive individuals with a genetic predisposition to essential hypertension, but with a normal glucose tolerance and without a genetic predisposition to NIDDM. Early insulin-secretion abnormalities may be the very first step towards the development of insulin resistance and an important factor initiating the hypertension in hypertension-prone individuals.
Andersen
U B
UB
Department of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, Denmark.
Dige-Petersen
H
H
Frandsen
E K
EK
Ibsen
H
H
Vølund
A
A
D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D015992:Body Mass Index; D002395:Catecholamines / Q000097:blood; D005260:Female; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000235:genetics* / Q000503:physiopathology; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male
D002395:Catecholamines; D007328:Insulin