Effect of dietary sodium on platelet alpha 2-adrenoceptors in young normotensive men with or without a family history of hypertension.
OBJECTIVE
To study the effects of genetics on the response of platelet alpha 2-adrenoceptors to a change in salt intake.


METHODS
Biochemical measurements and radioligand binding assays in platelets were performed in 11 normotensive male university students with a family history of essential hypertension (FH+) and in 17 students without a family history of hypertension (FH-). The 28 students were fed a high-sodium diet for 7 days and a low-sodium diet for 7 days.


RESULTS
In FH+ subjects the number of alpha 2-adrenergic receptors on platelet membrane fractions increased significantly from the high-sodium diet to the low-sodium diet, even though plasma noradrenaline concentrations tended to increase with the low-sodium diet. There was no change in the number of alpha 2-adrenoceptors in the FH--group. In both groups the radioligand binding affinity was decreased during a low-sodium period compared with in a high-sodium period.


CONCLUSIONS
In the FH+ subjects the change in platelet alpha 2-adrenoceptors associated with altered sodium status was similar to that seen in patients with salt-sensitive hypertension, suggesting that there is a genetic susceptibility to sodium.
Umemura
S
S
Second Department of Internal Medicine, Yokohama City University, Japan.
Hirawa
N
N
Hayashi
S
S
Toya
Y
Y
Minamisawa
K
K
Iwamoto
T
T
Kihara
M
M
Ishii
M
M
D000328:Adult; D001792:Blood Platelets / Q000187:drug effects*; D016022:Case-Control Studies; D015870:Gene Expression; D006801:Humans; D006973:Hypertension / Q000235:genetics*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D011869:Radioligand Assay; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects* / Q000235:genetics; D012982:Sodium, Dietary / Q000008:administration & dosage / Q000494:pharmacology*
D011942:Receptors, Adrenergic, alpha; D012982:Sodium, Dietary; D009638:Norepinephrine