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Author: Admin | 2025-04-28
Induction of menopause with elective hysterectomy and oophorectomy increased SSBP in middle age women.33 Concomitantly, others report that transdermal estrogen replacement therapy decreases salt sensitivity in postmenopausal women34 suggesting that estrogens exert protective effects against SSBP despite the counterintuitive female heightened salt sensitivity. In rat models of SSBP, notably the Dahl Salt-Sensitive (DSS) and the Spontaneously hypertensive rat, multiple groups have investigated the mitigating role of estradiol on SSBP. Ovary-intact and actively cycling female DSS rats demonstrate only a mild SSBP phenotype compared to the males of these models who depict greater increases in SSBP,35-37 which contrasts with clinical data suggesting that reproductive-aged women are more prone to SSBP. However, these models have been utilized to demonstrate the crucial role of female sex hormones in the development of SSBP. Ovariectomy ablates the sex difference in SSBP between male and female DSS rats.36,37 A caveat to this observation is that ovariectomy increases BP in the absence of high-salt diet in rat models.35,37,38 In addition, high-salt diet has no additive effect on ovariectomy-mediated elevations in BP in DSS rats, and reduction in salt intake is unable to restore BP in ovariectomy DSS female rats,38 which muddles conclusions of sex hormone contribution specifically in salt-sensitive increases in BP in female DSS. Moreover, ovariectomy appears to have no effects on salt sensitivity in previously hypertensive female rats (spontaneously hypertensive rats).35,37 Therefore, although female sex hormones incontestably exert protective effects on BP, the study of the contribution of female sex steroids to SSBP is confounded either by preexisting hypertension or salt-independent effects of ovariectomy on BP.Although menopause is associated with reduced estrogen and progesterone levels, it also involves an increase in the testosterone to estrogen ratio. Testosterone supplementation increases BP in young ovariectomy female spontaneously hypertensive rats on high salt diet39 and, seemingly congruently, suppression of endogenous androgen production by orchidectomy reduces BP in male rat models, including DSS, Sabra, and Sprague Dawley, which is restored to normal levels following testosterone supplementation.40-42 However, as observed with ovariectomy in the absence of high salt diet, testosterone supplementation in ovariectomy female rats and orchidectomy in male rats
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