To evaluate the age-related response of vasoactive factors during acute exercise,
young (n = 8, aged 23.6 ± 2 years) and old (n = 13, aged 77 ± 6 years) healthy volunteers
performed a stress test using a treadmill, and blood samples were taken before and
after exercise. There were neither basal (old people 77 ± 53 vs. young people 67.6
± 40 pg/ml) nor peak exercise-related (old people 77 ± 43 vs. young people 66.8 ±
34 pg/ml) differences in plasma adrenomedullin (AM) between both groups. AM did not
increase with exercise in either group. Regarding plasma cAMP, there were neither
basal nor exercise related differences, but this nucleotide increased with exercise
in both groups (old people p < 0.0001, young people p < 0.05). Plasma Atrial Natriuretic
Peptide (ANP) was higher in basal (116.3 ± 64 vs. 46.8 ± 21 pg/ml, p < 0.003) and
after exercise samples (150.2 ± 76.5 vs. 68.7 ± 29.5 pg/ml, p < 0.004) in old people
as compared with young people. Old people showed an increase in ANP with exercise
(p < 0.05), but in young people, though there was a trend to increase, it did not
reach statistical significance. There were neither basal nor exercise related differences
in plasma cGMP, but this nucleotide increased with exercise in both groups. Angiotensin
II (AT-II) levels were lower in basal and after exercise samples in old people as
compared with young people. AT-II levels did not increase with exercise in either
group. These data suggest that, with increasing age, the vascular tree develops resistance
to ANP and higher sensitivity to AT-II, while AM levels do not change. Exercise makes
ANP changes more evident, while AM and AT-II are not modified.
Key words
Adrenomedullin - Atrial Natriuretic Factor - Angiotensin II - cGMP - cAMP - Exercise
Test
