Sodium transport activity in cheek epithelial cells from adolescents at increased risk of hypertension.
Sodium transport including amiloride-sensitive Na+/H+ antiporter activity was measured in cheek epithelial cells of adolescents displaying either high or low BP tracking characteristics and in a subgroup of high BP tracking adolescents exhibiting a positive family history of hypertension. From the BP tracking behaviour of over 500 adolescents measured over a period of three years, 24 low BP tracking and 29 high BP tracking adolescents were recruited for the study. Cheek cells were collected from these subjects and proton-dependent, amiloride-sensitive Na+/H+ antiporter activity and the response of this antiporter to a proton gradient were measured. Cheek cell Na+/H+ antiporter activity was 50% lower (P = 0.0004) in the high BP tracking group (1.02 +/- 0.15 nmol Na+/mg protein/5 min (mean +/- SEM) compared with the activity in the low BP tracking group (2.05 +/- 0.24). A significantly lower Na+/H+ antiporter activity (69%; P < 0.01) was also apparent in the high BP tracking adolescents with family history of hypertension (n = 7) compared with the low BP tracking group. The graded response of cheek cell Na+/H+ antiporter activity to the proton gradient was 58% lower (P = 0.0039) for adolescents in the high BP tracking group compared with the low BP tracking group. Passive Na+ influx was also significantly lower in the cheek cells of the high BP tracking group. Our results therefore show that the activity of the Na+/H+ antiporter in cheek cells and the passive Na+ transport activity are lower in those adolescents considered at greatest risk of future development of essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
McMurchie
E J
EJ
CSIRO (Australia) Division of Human Nutrition, Glenthorne Laboratory.
Burnard
S L
SL
Patten
G S
GS
Smith
R M
RM
Head
R J
RJ
Howe
P R
PR
D000293:Adolescent; D000584:Amiloride / Q000494:pharmacology; D001692:Biological Transport; D002610:Cheek; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000235:genetics; D008297:Male; D009061:Mouth Mucosa / Q000166:cytology / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011522:Protons; D012307:Risk Factors; D012727:Sex Characteristics; D012964:Sodium / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism
D011522:Protons; D017923:Sodium-Hydrogen Exchangers; D010042:Ouabain; D000584:Amiloride; D012964:Sodium