Title:Circulating Aminopeptidase Activities in Men and Women with Essential Hypertension
Volume: 20
Issue: 38
Author(s): R. Sánchez-Agesta Ortega, J. M. Arias de Saavedra-Alías, A. Liébana-Cañada, B. Sánchez-Muñoz, J. M. Martínez-Martos and M. J. Ramírez-Expósito
Affiliation:
Keywords:
Hypertension, gender differences, renin-angiotensin system, aminopeptidases, sexual hormones, thyroid hormones.
Abstract: Essential hypertension is one of the major contributors to premature morbidity and mortality due to the incresased
risk for coronary heart disease, stroke, renal disease, peripheral vascular disease and vascular dementia for both men
and women. However, its basic causes remain unknown. In the present work we studied the activity of several proteolytic
regulatory enzymes related to renin-angiotensin-system (RAS) (aminopeptidase A, APA; aminopeptidase N, APN; aminopeptidase
B, APB; and insulin-regulated aminopeptidase, IRAP); with oxytocin regulation (oxytocinase); with the metabolism
of GnRH and TRH (pyrrolidone carboxypeptidase, Pcp); and with enkephalins metabolism (enkephalindegrading
activity, EDA), to elucidate their role in the mechanisms responsible of essential hypertension and to discuss
the possible gender differences. Serum samples of 53 individuals with essential hypertension and 60 healthy volunteers
were collected and used to assay enzyme activities, gonad hormones testosterone and estradiol, TSH and free thyroxin
(fT4). Differences were observed in APA, APN, Pcp and EDA specific activities, and in serum gonad hormone levels between
hypertensive and control groups. Only Pcp activity showed gender differences. Regarding the RAS, APA is reduced
while APN is increased, suggesting increased levels of angiotensin II and a facilitation of the conversion of angiotensin
III in angiotensin IV. Thus, the changes in several RAS-regulating specific activities and other enzyme activities
involved in the neuroendocrine modulation of gonad and stress-related functions are related to essential hypertension with
minor gender differences. Therefore, aminopeptidases constitute new elements for the knowledge of the causes of essential
hypertension and an alternative as therapeutic targets against the illness.
