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Influence of salt and estrogen on inner medullary NOS expression in female spontaneously hypertensive rats (SHR)
Author(s) -
Brinson Krystal N.,
Sullivan Jennifer C.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.968.4
Subject(s) - endocrinology , medicine , western blot , chemistry , blood pressure , estrogen , reabsorption , nitric oxide , medullary cavity , renal medulla , excretion , nitric oxide synthase , kidney , biochemistry , gene
Estradiol has been suggested to protect against salt‐sensitive hypertension. The renal inner medulla, the final site for Na+ reabsorption regulation, has an important role in blood pressure (BP) control. Nitric oxide (NO) regulates medullary water and Na+ excretion, and estradiol is associated with increased NO production. Thus, the aim of this study was to determine the effect of ovariectomy (OVX, at 11‐weeks) on salt sensitivity and renal medullary NOS protein expression in spontaneously hypertensive rats (SHR.) 14‐week old intact and OVX female SHR were placed on a normal salt (NS; 0.1% salt; N=6) or high salt (HS; 4% salt; N=8) diet for 2 weeks. BP was measured by telemetry. Inner medullary NOS protein expression was determined by Western blot. HS diet did not change BP in intact females (change in BP from baseline: week 1, 0.4±1 mmHg; week 2, 0.3±1 mmHg). HS increased BP in OVX at week 1 (9±2 mmHg), yet this effect was lost by week 2 (2±2 mmHg). NOS1 expression was similar in intact and OVX on NS (relative densitometric units (rdu) 0.5±0.2 vs. 0.5±0.03), however HS tended to increase expression (intact: 0.9±0.08; OVX: 1.7±0.5 rdu). NOS3 expression was significantly decreased by OVX on NS (1.3±0.2 vs. 0.5±0.2 rdu, p=0.4) and this effect was lost with HS (intact: 1.8±0.5; OVX: 1.6±0.3 rdu). We conclude that in female SHR, inner medullary NOS expression is regulated by both estrogen status and salt.