Effects of age, hypertension and HRT on serum aminopeptidase A activity.
OBJECTIVE
It is conceivable that aminopeptidase A (APA)/angiotensinase is involved in the pathogenesis of hypertension. The aim of this study was to evaluate the influences of age, hypertension and hormone replacement therapy (HRT) on serum APA activity in middle-aged and elderly women.


METHODS
Blood samples were collected from 117 women aged 40-69, 48 normotensive healthy women not receiving HRT, 57 normotensive women receiving HRT, and 12 hypertensive women (blood pressure >140/90 mmHg) with no medication. Serum APA activity was measured using alpha-glutamyl-p-nitroanilide as substrate spectrophotometrically.


RESULTS
Serum APA activity increased along with age between 40 and 69 in healthy women not taking HRT (r=0.351, P<0.05). Hypertensive women had higher serum APA activity than age-matched normotensive women (25.4+/-4.2 versus 22.4+/-3.4 microM/min; P<0.05) Compared with non-users of HRT, APA activity was elevated in women receiving HRT (23.9+/-3.8 versus 20.4+/-3.2 microM/min; P<0.05).


CONCLUSIONS
APA activity had a positive correlation with age in healthy women. Furthermore, hypertension and HRT up-regulated the serum APA activity significantly. The measurements of serum APA would be of value to elucidate the physiological and clinical roles of APA, although further studies are required.
Ijima
Mari
M
Department of Obstetrics and Gynecology, Nagoya University School of Medicine, 466-8550, Nagoya, Japan.
Nomura
Seiji
S
Okada
Mayumi
M
Ikoma
Yoko
Y
Ito
Tomomi
T
Mitsui
Takashi
T
Maeda
Osamu
O
Mizutani
Shigehiko
S
D000328:Adult; D000368:Aged; D000375:Aging; D000626:Aminopeptidases / Q000097:blood*; D016022:Case-Control Studies; D015914:Estrogen Replacement Therapy; D005260:Female; D043384:Glutamyl Aminopeptidase; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008875:Middle Aged
D000626:Aminopeptidases; D043384:Glutamyl Aminopeptidase