Endogenous nitric oxide (NO) is an important functional mediator in several physiological systems, including the reproductive system. However, when generated in excessive amounts for long periods, mainly during immunological reactions, NO is cytotoxic and cytostatic for invading microbes, as well as for the cells generating it and the tissues present around it. Since infertility associated with urogenital tract infection in males and females is also accompanied by reduced sperm motility and viability, it is possible that reduced fertility in these patients is due to NO-induced sperm toxicity. We therefore evaluated the direct effects of NO, chemically derived from S-nitroso-A'-acetylpenicillamine (SNAP, 0.012-0.6 mM) and sodium nitroprusside (SNP, 0.25-2.5 mM), on the motility and viability of human spermatozoa. Furthermore, we tested whether inhibition of NO synthesis prevents sperm motility and viability by incubating washed total cells present in the semen (spermatozoa, round cells) with /V-nitro-Larginine-methyl-ester (L-NAME), a NO synthesis inhibitor. Treatment of purified spermatozoa with SNAP or SNP decreased forward progressive sperm motility and straight line velocity, and also increased the percentage of immotile spermatozoa in a concentration-dependent manner. Furthermore, the percentage of immotile spermatozoa positively correlated with the percentage of dead spermatozoa. In contrast to freshly prepared SNAP, SNAP preincubated for 48 h had no effect on the motility and viability of the spermatozoa. Furthermore, as compared to untreated controls, a significantly higher percentage of forward progressive sperm motility as well as viability (P < 0.05) was maintained in washed semen incubated with L-NAME (0.15 mM). Seminal plasma concentrations of nitrite-nitrate (stabile metabolites of NO)/10 6 spermatozoa correlated positively (P < 0.05) with the percentage of immotile spermatozoa. Our results suggest that NO can cause sperm toxicity as well as inhibit sperm motility. In conclusion, excessive NO synthesis in response to infection and inflammation could be an important factor contributing to functional change of the spermatozoa, leading to their dysfunction and to infertility.

Postmenopausal women (PMW) have an increased risk of cardiovascular disease that is attenuated by hormone replacement therapy (HRT). Inasmuch as hypertension and atherosclerosis are associated with diminished endothelium-derived nitric oxide (NO), we investigated whether HRT augments NO release in PMW. We determined serum levels of nitrite/nitrate (NO2 + NO3) at baseline and during the 6th, 12th, and 24th months of the study in two groups of PMW. One group (HRT-PMW, n = 13) received continuous transdermal administration of 17 beta-estradiol (Estraderm-TTS-50) supplemented with oral norethisterone acetate (NETA) on days 1 through 12 of each month, and the other group (control PMW, n = 13) did not receive HRT. Blood samples in the HRT-PMW group were collected without regard to whether subjects were taking NETA at the time of blood sampling. Serum NO2 + NO3 levels increased in HRT-PMW for the duration of the study, whereas serum NO2 + NO3 levels remained unchanged in control PMW. When all samples regardless of timing of collection with respect to NETA treatment were included in the statistical analysis, the change in NO2 + NO3 levels in HRT-PMW was significantly greater compared with the change in control PMW (P = .037). Likewise, when only those samples collected when estradiol-treated subjects were not taking oral NETA were included in the statistical analysis, the change in NO2 + NO3 levels in the HRT-PMW group remained significant (P = .047) compared with control PMW.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract-Postmenopausal women (PMW) have increased incidence of cardiovascular disease, and estrogen substitution therapy has been shown to have cardloprotectlve effects. Since abnormal growth of cardiac fibroblasts (CFs) 1s associated with hypertension and myocardlal mfarctlon and estrogen mhlblts vascular smooth muscle cell (SMC) Key Words: estrogen(s) n phytoestrogens n 17P-estradloi n cardiac fibroblast n postmenopausal women n hormone replacement therapy n cardiovascular &sease n prohferatlon n hypertrophy S everal lines of evidence suggest that estrogens are cardloprotective First, women m the reproductive age group are protected against cardiovascular disease m comparison with men ' Second, onset of menopause m women 1s accompamed with ovanan dysfunction, decrease m clrculatmg estrogen levels, and increased incidence of cardiovascular disease.' Third, estrogen replacement therapy markedly reduces the nsk of cardiovascular &sease m postmenopausal women '8'Although the cardloprotectlve effects of estrogen m postmenopausal women (PMW) are well estabhshed, the mechanisms by which estrogen induces its cardloprotectlve effects are not fully understood Since coronary artery disease 1s the most frequent cause of death among women,2 most research has focused on evaluatmg the effects of estrogen on vascular cells In this regard, several Important findings are the following (1) Functional receptors for estrogen exist on both vascular endothehal and smooth muscle cells (SMCS),~ (2) estrogen has direct effects on vascular cells,3 (3) estrogen improves endothehal function and prevents endothehal damage,4 and (4) estrogen mhlblts mltogen-induced prohferatlon of SMCs, nugratlon of SMCs from the media to the mtlma, and deposltlon of extracellular matnx proteins (ECM) such as collagen 3 5 Since endothehal damage/dysfunction and increased SMC prohferanon, nugratlon, and ECM synthesis contributes to the vasooccluslve disorders associated with coronary artery dlsease,h estrogen may induce its protective effects by mtibmng the vascular remodelmg process. Indeed, numerous m vlvo studies m vanous female animal models have now shown that neomtlma formation m atherosclerosis and after balloon catheterinduced inJury 1s increased m the absence of estrogen and inhibited m the presence of estrogen.3'78Like SMCs urlthm the vasculature, abnormal growths of cardiac fibroblasts (CFs) also are lmportandy mvolved m the pathophyslology of cardiovascular diseases mcludmg cardiac remodeling induced by hypertension, myocardlal mfarctlon, and myocardal reperfuslon injury followmg lscherma 9 CFs that comprise 60% of the total heart cells contribute to pathologcal structural changes m the heart by undergoing prohferatlon, deposmng ECM proteins, and replacing myocytes with fibrotic scar tissue 9 Thus, CF-induced cardiac

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Abstract-Some estrogenic compounds modify vascular smooth muscle cell (SMC) biology; however, whether such effects are mediated in part by estrogen receptors is unknown. The purpose of this study was to evaluate whether the actions of clinically used estrogens on human aortic SMC biology are mediated by estrogen receptors. We examined the effects of various clinically used estrogens in the presence and absence of ICI 182,780, an estrogen receptor antagonist, on cultured human aortic SMC DNA synthesis ([ 3 H]thymidine incorporation), cellular proliferation (cell counting), cell migration (modified Boyden chamber), collagen synthesis ([ 3 H]proline incorporation), and mitogen-activated protein kinase activity. FCS-induced DNA synthesis, cell proliferation, collagen synthesis, platelet-derived growth factorinduced SMC migration, and mitogen-activated protein kinase activity were significantly inhibited by physiological (10 Ϫ9 mol/L) concentrations of 17␤-estradiol and low concentrations (10 Ϫ8 to 10 Ϫ7 mol/L) of 17␤-estradiol, estradiol valerate, estradiol cypionate, and estradiol benzoate but not by estrone, estriol, 17␣-estradiol, or estrone sulfate. The inhibitory effects of 17␤-estradiol and other inhibitory estrogens were completely reversed by 100 mol/L ICI 182,780, and the rank-order potency of various estrogens to inhibit SMC biology matched their rank-order affinity for estrogen receptors. The inhibitory effects of estrogens on SMC biology are in part receptor-mediated. Because the cardioprotective effects of hormone replacement therapy are most likely mediated by modification of SMC biology, whether hormone replacement therapy protects a given postmenopausal woman against cardiovascular disease will depend partially on the affinity of the estrogen for estrogen receptors in vascular SMCs. S ome epidemiological studies provide strong evidence that hormone replacement therapy (HRT) affords cardioprotection in postmenopausal women, 1 whereas other epidemiological studies and a recent clinical trial do not support this notion. 2,3 Although the reasons for these discordant findings are unknown, the inconsistent results reported to date may be due to heterogeneity in the responses of postmenopausal women to HRT. Indeed, in a given cohort of postmenopausal women, HRT has been shown to provide cardioprotective effects in only 50% to 60%. 4 To correctly interpret the results of completed clinical studies and to better design new clinical trials, it is critical to elucidate the independent variables that govern the cardioprotective effects of HRT.Our working hypothesis is that the degree of cardioprotection afforded by HRT is strongly influenced by the binding affinity of the specific estrogen to estrogen receptors in vascular cells and to the level of expression of estrogen receptors in vascular cells in an individual postmenopausal woman. The rationale for this hypothesis is 2-fold. First, several different types of estrogens are used clinically, 5 and estrogens differ greatly in their chemical characteristics, bi...