Læknablaðið : fylgirit - 01.06.1982, Blaðsíða 31

19
GHANGES IN INTRAEEYTHROCYTE CONCENTRATION AND TRANSMEMBRANE IN
FLUX AND EFFLUX OF SODIUM DURING SALT LOADING IN SUBJECTS WITH
AND WITHOUT HEREDITY FOR HYFERTENSION.
Ottar Gudmimdsson, Hans Herlitz, Olof Jonsson,and Göran Berg-
lund. Dept. of Medicine I, Surgery I and Urology, Unárversity
pf Göteborg, S.ahlgren's Hospital, Göteborg, Sweden.
An inherited abnormal handling of intracellular sodium has been
postulated in essential hypertensives. We investigated 17 young
normotensive men with heredity for hypertension (h) in two gen-
erations (father and grandfather) and 16 age matched control
subjects (c) with respect to intraerythrocyte sodium (ieNa),
sodium influx, and rate of sodium efflux. The determinations
were done during ordinary salt intahe and after a four weeh' s
salt load (12 g/day extra)
Intraerythrocyte sodium content was determined by flame photo-
metry. The membrane Na influx (mmol/100 ml x min) and rate
constant for Na efflux (min_”l) were calculated from uptalce val-
ues for j_n vitro during steady state conditions by using
a modified Keyn.es formula.
The hereditary subjects had a significantly higher IeNa dturing
basal conditions (9.8 - 0.9 ('H), 8.4 - 0.3 (c) mmol/l red cellSj
p 0.01). No difference in erythrocy^e water content was ob-
served. After salt loading both groups decreased significantly
to 8.3 - 0.3 (h) and 7.8 - 0.3 (c). There was no significant
difference between H and C in Na influx either on normal or on
high salt intake but the influx tended to rise in both groups
after salt loading. The rate constant for Na efflux was signi-
ficantly lower on normal salt intahe in those with heredity
(0.0038 - 0.0003 vs. 0.0050 - 0.0004 min~1, p 0.01). High salt
intahe tended to increase the efflux rate more in subjects with
heredity for hypertension than in control subjects but the diff-
erence was not statistically significant (0.0048 - 0.0003 (h)vs.
0.0053 - 0.0004 (c) min-1 during high salt. intalce).
Conclusion: Our results suggest that young men with heredity
for hypertension have a higher intraerythrocyte Na-concentratior.
secondary to a lower rate of Na efflux. The Na influx did not
differ between the two groups probably indicating an.unchanged
permeability in subjects with hereditv for hypertension.