Lymphocyte Na,K-ATPase is reduced in aged people.
Na,K-ATPase-dependent 86Rb uptake, maximum velocity (Vmax), Michaelis constant (Km) of the uptake, and [3H]-ouabain binding were investigated in the lymphocytes of 10 elderly subjects (age greater than 60 years), and in 10 middle-aged (41 to 60 years) and 10 young controls (age less than or equal to 40 years). 86Rb uptake was reduced in elderly versus both middle-aged and young subjects (20.14 +/- 3.30 v 35.60 +/- 2.67, P = .002, and v 36.53 +/- 4.49 nmol, P = .012), as was the number of [3H]-ouabain binding sites per cell (32,662 +/- 2,215 v 40,420 +/- 1,184, P = .011, and v 40,596 +/- 1,349, P = .014). Vmax was reduced in elderly v young subjects (1.20 +/- 0.10 v 1.64 +/- 0.13, P = .034), but not versus the middle-age group (1.20 +/- 0.10 v 1.54 +/- 0.12 nmol.min-1, NS). Km was no different among the three groups. No differences were found between middle-aged and young subjects. Significant correlations were observed between age and Na,K-ATPase-dependent 86Rb uptake (r = -.620, P = .00009), Vmax (r = -.439, P = .024), and [3H]-ouabain binding sites (r = -.648, P = .002). Moreover, the site number was positively correlated with both uptake (r = .635, P = .002) and Vmax (r = .554, P = .011). These differences were observed both in women and men. We conclude that there is an age-dependent reduction in lymphocyte Na,K-ATPase activity, which is fully manifested over 60 years, and that this alteration is probably due to the reduced number of functional units of Na,K-ATPase in advancing age.
Bozzo
C
C
Institute of Internal Medicine, University of Turin, Italy.
Goria
M
M
Marengo
C
C
Marena
S
S
Veglia
F
F
Pagano
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D001693:Biological Transport, Active; D001786:Blood Glucose / Q000378:metabolism; D004435:Eating; D005215:Fasting; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008214:Lymphocytes / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D010042:Ouabain / Q000378:metabolism; D011485:Protein Binding; D012016:Reference Values; D012413:Rubidium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood*
D001786:Blood Glucose; D007328:Insulin; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium