Sex Difference in Vascular Response to Atrial Natiuretic Peptide in SHR

ARRANZ C; ROMERO M; BOUCHET G; SAVIGNANO L; CANIFFI C.; ELESGARAY R.; COSTA A.

Jackson

Congreso; Physiology of Cardiovascular Disease: Gender Disparities; 2011

American Physiological Society

The aim was to investigate vascular effects of chronic infusion with atrial natriuretic peptide(ANP) in spontaneously hypertensive rats(SHR), look for sex differences. Methods: 10 weeks-old male (M) and female (F) SHR were infused(14 days, osmotic pumps) with ANP(100 ng/hr.rat) or saline (S).Systolic blood pressure(SBP,mmHg)  and nitrites and nitrates excretion(NOx,nmol/min.100g) were determined.  Morphological studies were performed in thoracic aorta sections stained with haematoxylin-eosin (media/lumen ratio,AML,mm/mm) and fibrosis signs with Sirius Red(SRA, score). Aortic NOS activity 14C L-arginine, pmol/g.tissue.min) was determined. Cardiac ventricle and kidney sections were stained with Sirius Red, to evaluate perivascular collagen in coronary(CA) and renal arteries(RA,µm/mm lumen). Results:   NOx  NOS AML   M S 2.4±0.2 264±8 74.1±2.3 M ANP 3.6±0.3* 353±6* 65.7±1.9* F S 3.2±0.2* 301±4* 65.6±2.5* F ANP 4.3±0.4# 410±3# 62.9±3.6 *p< 0,01 vs M S; #p<0,01 vs F S. Two-way ANOVA, Bonferroni´s post-hoc test. Vascular early fibrosis was higher in M than F SHR rats. ANP chronic treatment induced an increase in NO system activity and modified aorta remodeling only in males rats, probably improving aortic wall properties. Also, a reduction of early fibrosis in aorta and coronary and renal arteries was induced in both sexes. Funding source: CONICET-UBA, Argentina