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In coronavirus disease-19 (COVID-19), four major factors have been correlated with worse prognosis: aging, hypertension, obesity, and exposure to androgen hormones. Angiotensin-converting enzyme-2 (ACE2) receptor, regulation of the renin-angiotensin-aldosterone system (RAAS), and transmembrane serine protease 2 (TMPRSS2) action are critical for the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) cell entry and infectivity. ACE2 expression and RAAS are abnormal in hypertension and obesity, while TMPRSS2 is overexpressed when exposed to androgens, which may justify why these factors are overrepresented in COVID-19. Among therapeutic targets for SARS-CoV-2, we hypothesized that spironolactone, a long used and safe mineralocorticoid and androgen receptors antagonist, with effective anti-hypertensive, cardioprotective, nephroprotective, and anti-androgenic properties may offer pleiotropic actions in different sites to protect from COVID-19. Current data shows that spironolactone may concurrently mitigate abnormal ACE2 expression, correct the balances membrane-attached and free circulating ACE2 and between angiotensin II and Angiotensin-(1-7) (Ang-(1-7)), suppress androgen-mediated TMPRSS2 activity, and inhibit obesity-related RAAS dysfunctions, with consequent decrease of viral priming. Hence, spironolactone may provide protection from SARS-CoV-2, and has sufficient plausibility to be clinically tested, particularly in the early stages of COVID-19.

Introduction: Primary aldosteronism (PA) accounts for ∼10% of cases of hypertension in adults, however it’s a rare disease in children. We present a rare pediatric case with PA as the initial presentation of adrenocortical multiple hormone producing tumor. Case: A 7-year-old Japanese girl, who had right-sided hypoplastic leg and foot syndactyly, presented to our hospital due to abnormal ECG of ST depression at V6 on school health check-up. She showed normal growth, no signs of virilization nor Cushingoid appearance. She had elevated blood pressure (164/98 mmHg), low potassium (2.6–3.0 mEq/L) and low cardiac ejection fraction (30–40%). Her plasma aldosterone concentration (PAC) was 441 pg/mL and aldosterone/renin ratio (ARR) was 1470. Contrast-enhanced CT and MRI showed a right adrenal mass (34×22×30 mm) with high lipid content, which led to the diagnosis of primary aldosteronism by the right adrenal adenoma. Adrenal venous sampling failed to identify localization of aldosterone production. Since the possibility of bilateral production of aldosterone remained, the girl was treated with multiple anti-hypertensive medicine including spironolactone and potassium supplementation. Although the serum potassium levels were maintained within normal range, exercise-induced PVCs occurred 6 months after first visit. Abdominal US showed no changes in size of the tumor. Ten months later, she showed gradual weight gain without growth deceleration. Twelve months later, abdominal US revealed apparent enlargement of the right adrenal mass, and MRI scan showed a 156% increase in size of the right adrenal mass (32×50×53 mm). She showed further weight gain with moon face, hirsutism and acne. Hormonal analysis revealed elevated serum and urine cortisol levels (30–40μg/dL and 269–337 μg/m2/day, respectively), and suppressed ACTH levels with no diurnal variation. Serum testosterone levels elevated to 1.00 ng/mL and serum DHEA-S to 273 μg/dL. Retrospective analysis of serum testosterone at the first visit was already mildly elevated to 0.47 ng/mL. Although no distant metastases were detected before surgery, direct liver invasion was found at right adrenal tumor rejection. Clinical Lessons: Primary aldosterone producing adenoma is extremely rare in childhood. In our case, initially the adrenal tumor produced aldosterone predominantly, and it revealed to produce glucocorticoid and androgen later on. Androgen producing adrenal tumor in children tends to have malignant nature. Although initial presentation was compatible with the primary aldosteronism, intense follow-up with detailed monitoring of various hormone levels and images, and early surgical intervention should be considered.

Sex hormones contribute to sex differences in blood pressure. Inappropriate activation of the renin-angiotensin system is involved in vascular dysfunction and hypertension. This study evaluated the role of androgens (testosterone) in angiotensin II (Ang II)-induced increase in blood pressure, vascular reactivity, and cardiac hypertrophy. Eight-week-old male Wistar rats underwent sham operation, castration, or castration with testosterone replacement. After 12 weeks of chronic changes in androgen status, Ang II (120 ng/kg per minute) or saline was infused for 28 days via subcutaneous miniosmotic pump, and changes in blood pressure was measured. Vascular reactivity and Ang II receptor levels were examined in mesenteric arteries. Heart weight, cardiac ANP mRNA levels, and fibrosis were also assessed. Ang II infusion increased arterial pressure in intact males. The Ang II-induced increase in hypertensive response was prevented in castrated males. Testosterone replacement in castrated males restored Ang II-induced hypertensive responses. Castration reduced vascular AT(1)R/AT(2)R ratio, an effect that was reversed by testosterone replacement. Ang II-induced hypertension was associated with increased contractile response of mesenteric arteries to Ang II and phenylephrine in intact and testosterone-replaced castrated males; these increases were prevented in castrated males. Ang II infusion induced increased left ventricle-to-body weight ratio and ANP mRNA expression, indicators of left ventricular hypertrophy, and fibrosis in intact and testosterone-replaced castrated males, and castration prevented the increase in these parameters caused by Ang II. This study demonstrates that testosterone plays a permissive role in development and maintenance of Ang II-induced vascular dysfunction, hypertension, and cardiac hypertrophy.

20-HETE is a potent inducer of endothelial ACE in vitro and administration of lisinopril or losartan attenuates blood pressure in models of 20-HETE-dependent hypertension. The present study was undertaken to further define the relationship between 20-HETE and the renin-angiotensin system in hypertension using an angiotensinogen-deficient mouse (Agt+/−). Treatment of male AGT+/− with 5α-dihydrotestosterone (DHT) increased systolic BP from 102±2 to 125±3 mmHg; in comparison, the same treatment raised BP in wild type (WT) from 110±2 to 138±2 mmHg. DHT increased vascular 20-HETE levels in AGT+/− and WT from 1.5±0.7 and 2.1±0.6 to 13.0±2.0 and 15.8±4.0 ng/mg, respectively. Concurrent treatment with the 20-HETE antagonist, 20-hydroxyeicosa-6(Z), 15(Z)-dienoic acid (20-HEDE) prevented the increases in BP in both AGT+/− and WT mice. Administration of 20-HEDE at the peak of the DHT-induced BP increase (12 days) reduced BP to basal levels after 48 hours. Interestingly, basal levels of renal microvascular EETs were higher in AGT+/− compared to WT (55.2±9.7 vs 20.0±4.1 ng/mg) and treatment of AGT+/− with DHT decreased the levels of EETs (28.4±5.1 ng/mg). DHT-mediated changes in vascular EET level were not observed in WT mice. Vascular Cyp4a12 and ACE protein levels were increased in both AGT+/− and WT by 30–40% and decreased with concomitant administration of 20-HEDE. Lisinopril was as effective as 20-HEDE in preventing DHT-mediated increases in BP in both AGT+/− and WT mice. This study substantiates our previous findings that the RAS plays an important role in 20-HETE-mediated hypertension. It also proposes a novel interaction between 20-HETE and EETs.

Background Androgen deficiency produces heart failure, which can be ameliorated by testosterone supplementation. Cardiac fibrosis plays a critical role in the pathophysiology of heart failure. This study aimed to evaluate whether testosterone can attenuate cardiac fibroblast activity through modulating transforming growth factor (TGF)-β and angiotensin (Ang) II signaling. Methods Migration, proliferation, myofibroblast differentiation, collagen production, and transcription signaling were evaluated in adult male rat (weighing 300–350g) cardiac fibroblasts with and without incubation with testosterone (10nM) and co-administration of TGF-β1 (10ng/ml) or Ang II (100nM) by cell migration analysis, proliferation assay, soluble collagen measurement, zymographic analysis, immunofluorescence microscopy, real-time PCR and Western blot. Results Compared to those without testosterone, testosterone-treated fibroblasts exhibited less collagen production. Testosterone-treated fibroblasts also had less migration, proliferation, myofibroblast differentiation, and collagen production in the presence of TGF-β1, or had less collagen production with Ang II. Testosterone-treated fibroblasts had decreased phosphorylated Akt, mammalian target of rapamycin, and 4E binding protein-1 irrespective of TGF-β1 treatment and had increased matrix metalloproteinase (MMP)-2 in the presence of TGF-β1 treatment, and had decreased phosphorylated P38 and Smad 2/3 levels in the presence of Ang II. Cardiac fibroblasts with and without testosterone had similar mRNA and protein expressions of total Akt and total Smad 2/3 irrespective of TGF-β1 or Ang II treatment. Conclusion Physiological level of testosterone attenuated Akt and Smad 2/3 phosphorylation mediated by TGF-β1 and angiotensin II respectively, which can result in decreased cardiac fibroblast activation and potentially contribute to beneficial effects in heart failure.

Sexual dysfunction is a frequent adverse effect during antihypertensive therapy. However, the mechanisms responsible for these effects are not well understood. The renin-angiotensin system has been identified in testis where it may play a role in testicular function and be involved in the detrimental effects of antihypertensive drugs. Therefore, our objective was to compare the influence of captopril and propranolol on plasma testosterone levels and on hydrolyzing angiotensin's enzymes (angiotensinases) in the testis of spontaneously hypertensive rats (SHRs) and in control animals. Twenty-four adult male SHRs were used in this study; eight were treated with captopril in drinking water, 8 with propranolol, and 8 were controls. At the end of the 4 weeks treatment period, systolic blood pressure (SBP) was recorded, blood samples were collected, and the right testis was dissected after perfusion of the rat with saline. The soluble (Sol) and membrane-bound (MB) fractions were obtained after solubilization and ultracentrifugation. Fluorometric measurement of Sol and MB angiotensinase activities were performed using arylamide derivatives as substrates. Testosterone was measured by enzyme immunoassay. SBP decreased after captopril but did not change with propranolol treatment. Whereas captopril did not affect angiotensinase activities, highly significant reductions in Sol and MB angiotensinase activities, particularly glutamyl- and aspartyl-aminopeptidases, were observed after treatment with propranolol. Plasma testosterone decreased in captopril treated rats but propranolol had a greater effect. The present results support a general functional depression of the RAS cascade in the testis of propranolol-treated SHR, which may influence the sexual function of these animals.

Premenopausal women are protected to some extent from cardiovascular and kidney diseases. Because this protection weakens after menopause, sex hormones are believed to play an important role in the pathogenesis of cardiovascular and kidney diseases. The cardiovascular system and the kidneys are regulated by the renin-angiotensin-aldosterone system (RAAS), which in turn, appears to be regulated by sex hormones. In general, oestrogen increases angiotensinogen levels and decreases renin levels, angiotensin-converting enzyme (ACE) activity, AT(1) receptor density, and aldosterone production. Oestrogen also activates counterparts of the RAAS such as natriuretic peptides, AT(2) receptor density, and angiotensinogen (1-7). Progesterone competes with aldosterone for mineralocorticoid receptor. Less is known about androgens, but testosterone seems to increase renin levels and ACE activity. These effects of sex hormones on the RAAS can explain at least some of the gender differences in cardiovascular and kidney diseases.

Men exhibit a higher incidence of cardiovascular diseases than do women. The cardiovascular actions of sex steroids have been suggested as primary factors in mediating this sex difference. The mechanisms by which sex steroids, androgens and estrogens, mediate cardiovascular actions remain unclear. Excess aldosterone secretion has been associated with cardiovascular diseases. The hypothesis tested in this study was that at physiological concentrations, androgens stimulate and estradiol inhibits aldosterone secretion by human adrenal cells. In contrast to our hypothesis, physiological concentrations of sex steroids did not modify aldosterone secretion by H295R human adrenocortical cells. However, supraphysiological concentrations (300–1000 nM) of dihydrotestosterone (DHT) significantly stimulated basal and Angiotensin II-mediated aldosterone secretion. The stimulatory effect of DHT on aldosterone secretion was not blocked by the classical androgen receptor blocker flutamide. The stimulatory effect of DHT on aldosterone secretion was also independent of the intra-adrenal renin angiotensin system since it was neither modified by treatment with the Angiotensin II receptor type 1 blocker losartan or the Angiotensin Converting Enzyme inhibitor captopril. Inhibitors of the calmodulin/calmodulin-dependent protein kinase (CaMK) and protein kinase C intracellular signaling pathways abolished the DHT stimulatory effect on aldosterone secretion by H295R cells. In conclusion, physiological concentrations of sex steroids did not modify aldosterone secretion by human adrenal cells. However, supraphysiological concentrations of DHT stimulated aldosterone secretion by human adrenal cells by the calmodulin/CaMK and protein kinase C intracellular signaling pathways but independently of the classical androgen receptor. Supraphysiological doses of androgen may promote cardiovascular diseases via stimulation of aldosterone secretion.

Background: Disrupting the enzyme cytochrome P4a14 in mice leads to hypertension, which is more severe in male than in female mice and appears to be due to androgen excess. Androgens are known to increase expression of angiotensinogen,but the effect of androgens on proximal tubule transport is unknown. Objective: These studies aimed to determine the effect of androgens on proximal tubule transport. Methods: Proximal tubules from knockout (KKO) and wild-ttype (WWT) (SSV/1129) mice were perfused in vitro. Volume resorption (JJ v ) was measured using 3 H-methoxy inulin as a volume marker. In separate experiments, male Sprague-Dawley rats were given dihydrotestosterone (DDHT) injections IP for 10 days. Proximal tubule transport was measured in this model using in vivo microperfusion. The renal expression of angiotensinogen was measured by Northern analysis, and brush border membrane protein abundance of the sodium-hhydrogen exchanger isoform 3 (NNHE3) was measured by Western blotting in the control and DHT-ttreated rats. Results: Mean (SSE) Jv was significantly elevated in proximal tubules from KO mice compared with WT mice (11.11 [0.006] vs 0.77 [0.112] nL/mm . mm, respectively; P

Our laboratory uses a model of intrauterine growth restriction (IUGR) induced by placental insufficiency in the rat to examine the developmental origins of adult disease. In this model only male IUGR offspring remain hypertensive in adulthood, revealing sex-specific differences. The purpose of this study was to determine whether testosterone with participation of the renin-angiotensin system (RAS) contributes to hypertension in adult male IUGR offspring. At 16 wk of age a significant increase in testosterone (346 ± 34 vs. 189 ± 12 ng/dl, P < 0.05) was associated with a significant increase in mean arterial pressure (MAP) measured by telemetry in IUGR offspring (147 ± 1 vs. 125 ± 1 mmHg, P < 0.05, IUGR vs. control, respectively). Gonadectomy (CTX) at 10 wk of age significantly reduced MAP by 16 wk of age in IUGR offspring (124 ± 2 mmHg, P < 0.05 vs. intact IUGR) but had no effect in control (125 ± 2 mmHg). A significant decrease in MAP in intact IUGR (111 ± 3 mmHg, P < 0.05 vs. untreated intact IUGR) and castrated IUGR (110 ± 4 mmHg, P < 0.05 vs. untreated CTX IUGR) after treatment with enalapril for 2 wk suggests a role for RAS involvement. However, the decrease in blood pressure in response to enalapril was greater in intact IUGR (Δ36 ± 1 mmHg, P < 0.05) compared with CTX IUGR (Δ15 ± 2 mmHg), indicating an enhanced response to RAS blockade in the presence of testosterone. Thus these results suggest that testosterone plays a role in modulating hypertension in adult male IUGR offspring with participation of the RAS.

The proximal tubule contains an autonomous renin-angiotensin system that regulates transport independently of circulating angiotensin II. Androgens are known to increase expression of angiotensinogen, but the effect of androgens on proximal tubule transport is unknown. In this in vivo microperfusion study, we examined the effect of androgens on proximal tubule transport. The volume reabsorptive rate in Sprague-Dawley rats given dihydrotestosterone (DHT) injections was significantly higher than in control rats given vehicle injections (4.57 ± 0.31 vs. 3.31 ± 0.23 nl·min−1·mm−1, P < 0.01). Luminally perfusing with either enalaprilat (10−4M) to inhibit production of angiotensin II or losartan (10−8M) to block the angiotensin receptor decreased the proximal tubule volume reabsorptive rate in DHT-treated rats to a significantly greater degree than in control vehicle-injected rats. The renal expression of angiotensinogen was shown to be higher in the DHT-treated animals, using Northern blot analysis. The expression of angiotensin receptors, determined by specific binding of angiotensin II, was not different in the two groups of animals. Brush-border membrane protein abundance of the Na/H exchanger, a membrane transport protein under angiotensin II regulation, was also higher in DHT-treated rats vs. control rats. Rats that received DHT had higher blood pressures than the control rats but had no change in their glomerular filtration rate. In addition, serum angiotensin II levels were lower in DHT-treated vs. control rats. These results suggest that androgens may directly upregulate the proximal tubule renin-angiotensin system, increase the volume reabsorptive rate, and thereby increase extracellular volume and blood pressure and secondarily decrease serum angiotensin II levels.

A dipeptidyl carboxypeptidase activity in the Dunning rat prostate tumor was characterized. This enzyme demonstrated the most prominent properties of angiotensin converting enzyme (ACE): that is, it was stimulated by NaCl and Co(2+) and was potently inhibited by captopril. The enzyme solubilized by Triton X-100 had a molecular mass of 110 kDa as determined by gel filtration chromatography. The specific activity of ACE did not change with castration, indicating that ACE activities are not controlled by androgen. The role of ACE in the prostate and its tumors is not understood, but the ability of this enzyme to hydrolyze a number of bioactive peptides suggests that it may function in controlling the molecular forms or activity of regulatory peptides.

Chronic heart failure represents a leading cause of mortality and health care expenditure in developed countries. In the last 20 years, medical therapy of heart failure has dramatically changed thanks to the introduction of agents able to significantly reduce the neurohormonal hyperactivation that underpins the syndrome, and to the growing opportunities of electrical therapies. Although major advances in terms of improved survival and quality of life have been achieved, the reduction in the burden of heart failure is still the primary goal of cardiovascular societies. In the last decades, other research lines have also grown to complement the neurohormonal paradigm. It is increasingly evident that several hormonal systems are down-regulated or impaired in patients with heart failure, including growth and thyroid hormones, androgens and insulin. These abnormalities could be considered interrelated and linked, in turn, to the neurohormonal and cytokine hyperactivation. Since most of these alterations provide prognostic information, these new lines of evidence support the extension of the classical neurohormonal scheme to a more comprehensive pathophysiological model that includes multiple hormonal and metabolic deficiencies. This chapter examines the evidence in support of this concept. Preliminary experience concerning targeted hormonal supplementation or metabolic modulation is also briefly reviewed in this article.

Chronic heart failure represents a leading cause of mortality and health care expenditure in developed countries. In the last 20 years, medical therapy of heart failure has dramatically changed thanks to the introduction of agents able to significantly reduce the neurohormonal hyperactivation that underpins the syndrome, and to the growing opportunities of electrical therapies. Although major advances in terms of improved survival and quality of life have been achieved, the reduction in the burden of heart failure is still the primary goal of cardiovascular societies. In the last decades, other research lines have also grown to complement the neurohormonal paradigm. It is increasingly evident that several hormonal systems are down-regulated or impaired in patients with heart failure, including growth and thyroid hormones, androgens and insulin. These abnormalities could be considered interrelated and linked, in turn, to the neurohormonal and cytokine hyperactivation. Since most of these alterations provide prognostic information, these new lines of evidence support the extension of the classical neurohormonal scheme to a more comprehensive pathophysiological model that includes multiple hormonal and metabolic deficiencies. This chapter examines the evidence in support of this concept. Preliminary experience concerning targeted hormonal supplementation or metabolic modulation is also briefly reviewed in this article.

Nitrites and nitrates are consumed nonchalantly in diet. Organic nitrates are also used as vasodilators in angina pectoris, but the therapy is associated with tolerance whose mechanism remains elusive. Previously, we found inorganic nitrate inhibited steroidogenesis in vitro. Because adrenocorticoids regulate water and electrolyte metabolism, tolerance may ensue from steroid deficiency. We have studied the effects of nitrite and nitrate on in vitro synthesis and in vivo blood levels of steroid hormones. In vitro, nitrite was more potent than nitrate in inhibiting human chorionic gonadotropin (hCG)-stimulated androgen synthesis by Mouse Leydig Tumor cells. At concentrations above 42 mM, nitrite completely inhibited androgen synthesis, and, unlike nitrate, the inhibition was irreversible by increasing hCG concentration. The cAMP production remained intact but reduced with both ions. The nitric oxide (NO) scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide (c-PTIO) significantly increased hCG- or cAMP-stimulated androgen synthesis in all buffers, suggesting that NO is a chemical species directly involved in the nitrite/nitrate-induced inhibition. This is further supported by c-PTIO countering the inhibitory action of methylene blue on androgen synthesis. Rats given distilled water containing 50 mg/L NaNO(2) or NaNO(3) for 4 weeks drank significantly less daily. At the end, their blood corticosterone and testosterone levels were significantly decreased. The adrenocortical histology showed bigger lipid droplets, which are pathogonomic of impaired steroidogenesis. Nitrite and nitrate are metabolized to NO, which binds heme in cytochrome P450 enzymes, thereby inhibiting steroidogenesis. Therapeutic nitrates likewise may decrease adrenal (and gonadal) steroidogenesis. Cortisol deficiency would impair water excretion causing volume expansion, and aldosterone deficiency would cause sodium loss and raised renin. Paradoxically, volume expansion without sodium retention and raised renin has all been reported in tolerance.

Adipose tissue is an important source of angiotensinogen (ATG), and hypertension is commonly associated with android obesity. Therefore, we tested the hypothesis that androgens may control ATG gene expression and secretion in rat fat cells. In intact male rats, ATG mRNA expression (Northern blot and co-reverse transcription-polymerase chain reaction analysis) and protein secretion were significantly higher in deep intra-abdominal (perirenal and epididymal) than in subcutaneous adipocytes. After castration, ATG mRNA was reduced almost 50% in the three fat deposits, with parallel changes in ATG protein secretion. Conversely, testosterone treatment fully restored the ATG mRNA decrease after castration, whatever the anatomical origin of the adipocytes. Finally, a 24-h in vitro exposure of perirenal fat cells or differentiated preadipocytes from castrated rats to testosterone or dihydrotestosterone (10 nM free hormone concentration) increased ATG mRNA expression by 50–100%, an effect that was prevented by the anti-androgen cyproterone acetate. These data, demonstrating both in vivo and in vitro androgen induction of ATG mRNA expression in rat adipocytes, add further weight to the hypothesis of a link between adipose tissue ATG production, androgens, and android obesity-related hypertension.

Background: The presence of extrarenal or local renin-angiotensin system (RAS) has been noted in several tissues, although its functions have not yet been clarified. Renin from the coagulating gland (CG) is the most recently discovered local RAS and is a significant subject for investigation because large amounts of both mRNA and proteins are detected in this organ. Recently, it has been reported that testosterone influences renin synthesis in several extrarenal tissues, although it has no effect on intrarenal renin. Therefore, it is possible that CG renin is also regulated by testosterone. Methods: Forty-four male C57BL/6 mice, aged 3 wk to 6 mo, were used in studies on the ontogeny and androgen regulation of the RAS in the CG. The tissues were fixed with Bouin's solution and paraffin sections were stained with immunohistochemical methods using antirenin antiserum. In each immunostained section, the relative number of renin-containing cells in terminal portions of the CG were counted. Results: Immunoreactivity for renin was first detected at 6 wk after birth. After that time, the number of renin-containing cells gradually increased throughout the experiment. In adults, several patterns of renin immunoreactivity were demonstrated in almost all epithelial cells of CGs, specifically; (1) basolateral granular reaction, (2) diffuse immunoreactivity throughout the cytoplasm, and (3) restricted nuclear reaction. Excretory products of some terminal lumina were also found to be positive for renin. At 10 days after castration, renin-containing cells in ductal termini were decreased and remained at low levels until at 4 wk after castration. After testosterone injection, numerical values of renin-containing cells were high at 1 wk and then decreased at 2–3 wk. Conclusion: It is suggested that CG renin of the mouse is expressed together with sexual maturation during development and that it depends on the testis, possibly the male sex hormone. © 1995 Wiley-Liss, Inc.

Androgen plays an important role in blood pressure regulation. Epidemiological studies have shown that men have a higher prevalence for developing hypertension than aged-matched, premenopausal women. Interestingly, postmenopausal women and women with polycystic ovary syndrome, both of which have increased endogenous androgen production, have elevated risks for hypertension suggesting that androgen may contribute to its development. Studies from our laboratory and others have provided substantial evidence that 20-hydroxyeicosatetraenoic acid (20-HETE) mediates the hypertension seen in rodents treated with androgen. 20-HETE is the cytochrome P450 (CYP)-derived ω-hydroxylated metabolite of arachidonic acid. 20-HETE plays a complex role in blood pressure regulation. In the kidney tubules, 20-HETE decreases blood pressure by promoting natriuresis, while in the microvasculature it has a pressor effect. In the microcirculation, 20-HETE participates in the regulation of vascular tone by sensitizing the smooth muscle cells to constrictor stimuli and contributes to myogenic, mitogenic and angiogenic responses. In addition, 20-HETE acts on the endothelium to promote endothelial dysfunction and endothelial activation. Recently, we have demonstrated that 20-HETE induces endothelial ACE thus setting forth a potential feed forward mechanism through activation of the renin-angiotensin-aldosterone system. In this review, we will discuss the pro-hypertensive effects of 20-HETE and its role in androgen-induced vascular dysfunction and hypertension.

Introduction The objective of this study is to investigate the effects of androgen on renal sodium excretion and renal functional in sodium-loaded rats. Methods Sixty male Wistar rats aged 8 weeks were used, of which 48 underwent orchiectomy and the other 12 underwent a sham procedure. The 48 orchiectomized rats were randomly divided into 4 groups (12/group): castrated rats (Cas), testosterone-supplemented castrated rats (TC), flutamide (androgen receptor blocker)-treated castrated rats (FC) and flutamide-treated testosterone-supplemented castrated rats (FTC). The 12 sham-operated rats served as controls. All 60 rats were fed with 8% NaCl chow for 8 weeks. Systemic blood pressure (BP) was recorded at 0, 4 and 8 weeks. Sodium excretion, microalbuminuria and creatinine clearance were calculated before and at the end of the experiment. Circulating levels of testosterone and angiotensin II and plasma renin activity were measured by radioimmunological method at the end of the experiment. Results BP of controls and TC was higher at 8 weeks than at baseline; BP of Cas, FC or FTC was lower than that of controls. Plasma renin activity and angiotensin concentrations were lower in Cas, FC and FTC (groups with testosterone absent or blocked) than in controls and TC (groups with testosterone intact). Cas, FC and FTC displayed less microalbuminuria, higher sodium excretion and higher creatinine clearance than control and TC. Conclusions In salt-loaded rats, testosterone seems to activate the renin-angiotensin system, resulting in sodium retention, higher BP and renal injury.

Local or tissue renin angiotensin systems are thought to participate in cardiovascular regulation. However, little information is available on the mechanisms by which renin and angiotensinogen synthesis and secretion are regulated in these tissues. In view of the importance of steroid hormones in the regulation of hepatic angiotensinogen, we have examined the effects of dexamethasone, ethinyl estradiol, or dihydrotestosterone on angiotensinogen gene expression in peripheral or cerebral tissues of Wistar Kyoto (WKY) or spontaneously hypertensive rats (SHR). Following a single injection of dexamethasone (7 mg/kg) the concentrations of angiotensinogen mRNA increased in nearly all organs examined. The differences to controls were higher in SHR than in WKY. Dexamethasone in low doses (10 micrograms/kg/day) given for 10 days did not alter angiotensinogen mRNA or blood pressure in control animals, but increased both parameters in the hypertensive strain. The response to a single dose of ethinyl estradiol (3 mg/kg) was not as uniform as that to dexamethasone, and a tendency for a higher sensitivity was found in SHR. High stimulation rates were found in liver and kidneys of both strains. A single dose of dihydrotestosterone (10 mg/kg) did not significantly affect angiotensinogen mRNA in any organ. Only when a high dose of 50 mg/kg was given daily for 20 days, was angiotensinogen mRNA increased in some tissues. These data indicate that glucocorticoids and estrogens participate in the regulation of angiotensinogen gene expression in several extrahepatic tissues. The higher sensitivity to glucocorticoids in SHR may be relevant for the development of hypertension in this strain.

Background: There is a poorly understood association between obesity and hypertension. We demonstrated abnormalities of adrenal androgen and cortisol metabolites in four hypertensive obese children. Patients: Four males (aged 10 to 15 years) were evaluated for systolic blood pressures consistently above the 99.6 th percentile. All were overweight with BMI ranging from 27-35. Clinical examinations, renal ultrasound and DMSA scans were normal. Plasma electrolytes, renin, aldosterone, cortisol, testosterone, ACTH and TSH were normal. 24-Hour urinary steroid profiles showed a generalised excess of adrenal androgen and cortisol metabolites in all cases. Relevant recognised disorders of adrenal androgen and cortisol metabolism were excluded. Conclusion: There is no clinical condition explaining these abnormal urinary steroid profiles. These results support previous findings and provide new data on abnormal urinary adrenal androgen excretion in obese hypertensive patients. Further studies may determine the relationship between obesity, hypertension and the observed abnormalities of urinary steroid excretion.

The regulation of angiotensinogen gene expression by steroid hormones in the rat liver has been examined. In the intact animal, dexamethasone (7 mg/kg ip) and estradiol (7 mg/kg sc) caused an increase in plasma angiotensinogen, which became first apparent after 5 or 9 h, respectively, and resulted in plasma concentrations 4.6- and 1.9-fold higher than in controls at 24 h. These changes were preceded by comparable increases in hepatic angiotensinogen messenger RNA (mRNA). In contrast, dihydrotestosterone (10 mg/kg sc) failed to alter plasma angiotensinogen, although hepatic angiotensinogen mRNA and total RNA were slightly elevated. In isolated hepatocytes exposed to either dexamethasone or estradiol (10 microM each) angiotensinogen mRNA started to increase within less than 1 or 3 h, respectively, followed, with a further time lag of about 2 h, by an increase in secretion rate of angiotensinogen. Dihydrotestosterone (10 and 100 microM) induced a rapid increase in total hepatocyte RNA (1.3-fold) and angiotensinogen mRNA (2-fold) with a peak at 2 h. Surprisingly, angiotensinogen secretion remained either unaltered (10 microM dihydrotestosterone) or even decreased (100 microM dihydrotestosterone). In a hepatoma cell line (FT02B) and a subclone (Fe 33) stably transfected with the human estrogen receptor, dexamethasone and estradiol induced an increase in angiotensinogen mRNA and secretion with the same characteristics as in hepatocytes. In conclusion, in this study a direct effect of estradiol on angiotensinogen mRNA and secretion in hepatocytes could be established, which differs from that of dexamethasone by a delayed onset of action. The observation, both in vivo and in vitro, that dihydrotestosterone induced an increase in total RNA and angiotensinogen mRNA, which is not accompanied by an increased angiotensinogen secretion, cannot be explained at present. This study also demonstrates the usefulness of a hepatoma cell line stably transfected with the estrogen receptor gene for the investigation of estrogen-dependent effects in vitro.

Prostate cancer is highly prevalent in Western society, and its early stages can be controlled by androgen ablation therapy. However, the cancer eventually regresses to an androgen-independent state for which there is no effective treatment. The renin-angiotensin system (RAS), in particular the octapeptide angiotensin II, is now recognised to have important effects on growth factor signalling and cell growth in addition to its well known actions on blood pressure, fluid homeostasis and electrolyte balance. All components of the RAS have been recently identified in the prostate, consistent with the expression of a local RAS system in this tissue. This review focuses on the role of the RAS in the prostate, and the possibility that this pathway may be a potential therapeutic target for the treatment of prostate cancer and other prostatic diseases.

Testosterone, a steroid hormone which increases blood pressure by hitherto unknown mechanisms, is known to induce renin synthesis in the submandibular gland (SMG) of mice. Since renin as well as all other components of the renin-angiotensin system are present in organs important for cardiovascular control, e.g. the kidney, heart, adrenal gland and brain, it is of interest to study the effect of testosterone on renin gene expression in these organs. Renin messenger (m) RNA concentrations were measured by a solution hybridization assay using a 32P-labeled mouse SMG renin complementary (c) RNA as a radioactive probe (detection limit: 1 pg renin mRNA). Measurements were performed after 2 h and after 2, 7, 14 and 21 days of dihydrotestosterone (DHT) treatment in female NMRI mice. Renin mRNA concentration (values are expressed as pg renin mRNA/ micrograms total RNA) in the SMG was significantly increased after 7 days (108 +/- 22 in controls versus 630 +/- 101 in DHT-treated mice), after 14 days (83 +/- 15 in controls versus 743 +/- 83 in DHT-treated mice) and after 21 days (107 +/- 30 in controls versus 579 +/- 76 in DHT-treated mice), but did not reach levels found in untreated male NMRI mice (1021 +/- 84). In the kidney, a decrease was observed within 21 days, from 43 +/- 4 and 40 +/- 4 to 29 +/- 2 and 22 +/- 1.7 pg/micrograms in controls and DHT-treated groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The aim of this review is to explore the dysregulation of adrenocortical secretions as a major contributor in the development of obesity and insulin resistance. Disturbance of adipose tissue physiology is one of the primary events in the development of pathologies associated with the metabolic syndrome, such as obesity and type 2 diabetes. Several studies indicate that alterations in metabolism of glucocorticoids (GC) and androgens, as well as aldosterone in excess, are involved in the emergence of metabolic syndrome. Cross talk among adipose tissue, the hypothalamo-pituitary complex, and adrenal gland activity plays a major role in the control of food intake, glucose metabolism, lipid storage, and energy balance. Perturbation of this cross talk induces alterations in the regulatory mechanisms of adrenocortical steroid synthesis, secretion, degradation, and/or recycling, at the level of the zonae glomerulosa (aldosterone), fasciculata (GC and GC metabolites), and reticularis (androgens and androgen precursors DHEA and DHEAS). As a whole, these adrenocortical perturbations contribute to the development of metabolic syndrome at both the paracrine and systemic level by favoring the physiological dysregulation of organs responsive to aldosterone, GC, and/or androgens, including adipose tissue.

Men are at greater risk of cardiovascular and renal diseases than women. Several hypertensive rat models also exhibit gender differences in blood pressure. Although the mechanisms responsible for these gender differences are not clear, androgens have been shown to promote hypertension. Testosterone is produced by Leydig cells under the regulation of catecholamines acting through both alpha- and beta-adrenoceptors. Some investigators have postulated a putative role of angiotensin II (Ang II) in modulating the action of gonadotropin in Leydig cells, inhibiting testosterone production. In the present work, we analysed the potential mechanism by which the testicular renin-angiotensin system (RAS) decreases the serum circulating levels of testosterone after the in vivo administration of the long-acting selective alpha(1)-adrenergic receptor antagonist doxazosin. RAS was analysed through assessment of the activity of its proteolytic regulatory enzymes. We can conclude that the testicular testosterone production, at least in rat, is regulated by catecholamines through a mechanism involving alpha(1)-adrenergic receptors and RAS, with a putative role for Ang III. Because doxazosin is usually used as a pharmacological therapy in the treatment of hypertension and benign prostatic hyperplasia, our results could also indicate that its benefits are due, at least in part, to decreased serum circulating levels of testosterone.

Female gender is associated with better renal function and resistance to renal injury, suggesting that an oestrogen-based effect or increased androgenic effects are responsible. Studies in rodents have confirmed a biological basis for this, based on the differential effects of androgens and oestrogens on the normal and diseased kidney. Many researchers in the field believe that the pre-menopausal levels of oestrogen are key to the protection observed in females. The key pressor effects of the renin-angiotensin (RA) system are due to both direct vasoconstrictory properties and alterations in renal control of extracellular fluid volume. Additionally, the RA has been shown to promote diverse aspects of renal injury. RA activity is positively modulated by androgens and antagonized by oestrogens. Nitric oxide (NO) is a potent vasorelaxant with a key role in renal control of extracellular fluid homeostasis. NO can variously have both protective and deleterious effects on renal injury. Endogenous oestrogen has an anti-hypertensive effect as well as protective effects against cell and organ damage, many of which are mediated via increases in NO generation. We examine how the RA- and NO-generating systems may underpin key aspects of gender differences in normal renal function and renal disease.

All forms of hypertension studied to date are caused by a defect in the handling of sodium and water by the kidney. There is a shift to the right in the pressure-natriuresis relationship (higher blood pressure) in which a hypertensive individual must increase blood pressure in order to excrete a normal sodium load. There are sex differences in blood pressure control in humans and animals, with males having higher blood pressure than females. However, blood pressure increases in some women after menopause. The mechanisms that play a role in hypertension, and have been studied extensively, include the renin-angiotensin-aldosterone system, endothelin, oxidative stress, the sympathetic nervous system, androgen/estrogen ratio, and obesity.

Objective The aim of the study was to compare the effect of spironolactone (antagonist of mineralocorticoid and androgen receptors) versus spironolactone plus licorice (agonist of mineralocorticoid receptors and mild inhibitor of androgen synthesis) on plasma renin activity, aldosterone and androgen levels in women with polycystic ovary syndrome (PCOS). Study design Thirty-two women with PCOS were divided into two groups: 16 received 100 mg spironolactone and 16 spironolactone plus 3.5 g of licorice a day. Blood pressure, body mass index, serum electrolytes, plasma renin activity, plasma aldosterone and cortisol, serum testosterone, and urinary tetrahydrocortisol/tetrahydrocortisone ratio were measured before and during treatment. Results Mean blood pressure was significantly reduced during spironolactone treatment, while it was unchanged in women receiving spironolactone plus licorice. Twenty percent of women treated with spironolactone and none treated with the addition of licorice complained of symptoms related to volume depletion. Consistently, the activation of the renin–aldosterone system was significantly lower during spironolactone plus licorice than with spironolactone alone. The prevalence of metrorrhagia was lower in the combined therapy. Conclusions In patients with PCOS the mineralocorticoid properties of licorice can reduce the prevalence of side effects related to the diuretic activity of spironolactone.

Background. There are conflicting reports about the importance of the renin–angiotensin system (RAS) on erythropoietin (Epo) sensitivity in haemodialysis patients, but the role of gender has not been studied specifically. The hypothesis underlying this study is that Epo resistance associated with RAS blockade (RASB) is specific to men and related to drug-induced lowering of circulating testosterone. Methods. Men and women undergoing chronic haemodialysis were divided into groups according to whether or not they were receiving RASB. Serum was collected pre-dialysis for determination of free testosterone levels by enzyme immunoassay. Routine laboratory data and Epo doses were collated and analysed for the 3 month period prior to the measurement of the hormone level. Results. Control women required more Epo than control men (P ¼ 0.002), but the Epo doses between men and women with RASB were similar. Men with RASB required more Epo than control men (P ¼ 0.002), but RASB had no effect on Epo requirements in women. There was a significant relationship between age and testosterone levels in control men (P ¼ 0.01) that was not present in men taking RASB. RASB was associated with lower levels of serum testosterone in men

The purpose of this study was to evaluate the physiological significance of a tissue renin-angiotensin system in the proximal tubule of the kidney. To accomplish this, we produced mice that express human renin (hREN) under the control of the kidney androgen-regulated promoter (KAP), which is androgen responsive. One of the lines expressed the hREN transgene primarily in the kidney. Renal expression of the transgene was undetectable in females but could be induced by testosterone treatment. Because the renin-angiotensin system is species specific, we bred KAP2-hREN mice with the mice expressing human angiotensinogen under the same promoter (KAP-hAGT) to produce offspring that expressed both transgenes. We measured mean arterial blood pressure (MAP) in the carotid artery of double-transgenic and control mice using radiotelemetry. Double-transgenic female mice had a normal baseline MAP (116 ± 4 mmHg, n = 8), which increased by 15 mmHg after 2 wk of testosterone treatment, and returned to baseline after elimination of the testosterone pellet. The change in arterial pressure paralleled the change in plasma testosterone. There was no MAP change in testosterone-treated control littermates. We conclude that dual production of renin and angiotensinogen in the renal proximal tubule can result in a systemic increase in arterial pressure. These data support a role for a tissue-specific renin-angiotensin system in the renal proximal tubule that contributes to the regulation of systemic blood pressure.

A sexual dimorphism in hypertension has been observed in both human and laboratory animal studies. The mechanisms by which male sex hormones regulate cardiovascular homeostasis are still not yet fully understood and represent the subject of this study. The possible involvement of androgen receptors in the development of hypertension and end-organ damage in transgenic rats harboring the mouse Ren-2 renin gene [TGR(mREN2)27] was studied. Male TGR(mREN2)27 rats were treated with the androgen receptor antagonist Flutamide starting at 4 wk of age. Also, an androgen receptor mutation (testicular feminization mutation [tfm]) was introduced in these rats by crossbreeding male TGR(mREN2)27 rats with tfm rats. The resulting offspring male rats that contain the tfm mutation are insensitive to androgens. Flutamide treatment or tfm mutation produced a significant attenuation of the development of hypertension. Besides a reduction in cardiac hypertrophy, urinary albumin excretion was blunted and no histologic characteristics of end-organ damage were observed in the kidney after Flutamide treatment. Testosterone levels increased 15-fold after Flutamide treatment and 2.7-fold by the tfm mutation. Also, plasma estrogens and luteinizing and follicle-stimulating hormones were significantly increased. Plasma renin concentrations and activity but not plasma angiotensinogen were reduced. Our results indicate that androgens contribute not only to the development of hypertension, but even more importantly to end-organ damage in TGR(mREN2)27 rats.

Gender differences have been described in the response of the cardiovascular system to a number of stimuli, including ventricular remodeling in response to pressure overload, but the molecular basis for these differences remains unclear. Because gender differences in the cardiac expression of angiotensin-converting enzyme (ACE) could contribute to differences in myocardial remodeling, we examined myocardial ACE expression in age-matched male and female mice. Ventricular ACE was more abundant in male than female mice at both mRNA and protein levels. These differences became apparent once the mice reached sexual maturity and became more pronounced with increasing age. The influence of mouse gonadal status on ventricular ACE expression was also examined. Oophorectomy slightly increased ACE levels in female mice, whereas ventricular ACE levels were substantially decreased in androgen-deprived males. The antithetical changes in ventricular ACE abundance seen in agonadal male and female mice suggest that testosterone as well as estrogen may play a role in regulating ACE expression in the heart.

Abstract —Men are at greater risk for cardiovascular and renal disease than are age-matched, premenopausal women. Recent studies using the technique of 24-hour ambulatory blood pressure monitoring have shown that blood pressure is higher in men than in women at similar ages. After menopause, however, blood pressure increases in women to levels even higher than in men. Hormone replacement therapy in most cases does not significantly reduce blood pressure in postmenopausal women, suggesting that the loss of estrogens may not be the only component involved in the higher blood pressure in women after menopause. In contrast, androgens may decrease only slightly, if at all, in postmenopausal women. In this review the possible mechanisms by which androgens may increase blood pressure are discussed. Findings in animal studies show that there is a blunting of the pressure-natriuresis relationship in male spontaneously hypertensive rats and in ovariectomized female spontaneously hypertensive rats treated chronically with testosterone. The key factor in controlling the pressure-natriuresis relationship is the renin-angiotensin system (RAS). The possibility that androgens increase blood pressure via the RAS is explored, and the possibility that the RAS also promotes oxidative stress leading to production of vasoconstrictor substances and reduction in nitric oxide availability is proposed.

We previously reported a novel transgenic model expressing human angiotensinogen from the kidney androgen-regulated protein promoter, and demonstrated sexually dimorphic expression. Herein, we investigated the hormonal regulation of this transgene. Testosterone increased transgene expression in female mice in a dose- and time-dependent manner and was not detectable 3-days after treatment was halted. High doses of estrogen were required to induce the transgene. Expression of transgene mRNA decreased after castration of male transgenic mice. As in females, however, transgene expression could be induced after administration of testosterone. Flutamide, an androgen receptor antagonist, dose dependently blocked transgene expression in males and blunted the induction caused by testosterone in females. Neither testosterone nor estrogen altered the proximal tubule cell-specific expression of the transgene. The data suggest that the level of transgene expression in this model can be controlled temporally and in magnitude by manipulating the levels of androgen. The fortuitous androgen regulation of this transgene can be used as a molecular “on-off” switch to control transgene expression and potentially manipulate blood pressure levels in this model.

Objectives To evaluate whether renin and angiotensinogen gene expression in females from two strains of rats that share the same autosomes and X chromosomes differs. Female SHR/y rats have the parental Wistar-Kyoto rat autosomes and X chromosomes and have no chromosomes of spontaneously hypertensive rat origin; thus they are genetically equivalent to female Wistar-Kyoto rats. Design and methods Because these genes are regulated by steroid hormones, we investigated the effects of removal of estrogen (ovariectomy) and addition of androgen (testosterone implants) on three groups of female SHR/y rats and the parental rat strain Wistar-Kyoto rat with groups of intact (control) rats, rats subjected to ovariectomy at age 3 weeks, and rats subjected to ovariectomy with a testosterone implant at age 3 weeks. Results The combination of removing estrogen early in development and supplementing the ovariectomized females with testosterone revealed strain differences in response of blood pressure. Renin and angiotensinogen messenger RNA levels appear to be regulated coordinately within each strain, although actual levels of messenger RNA differ between the strains. Conclusions Similar patterns of responses of renin and angiotensinogen genes to ovariectomy and ovariectomy plus testosterone suggest that regulation of the genes is likely to be similar or coordinate. Differences in regulation of renin-angiotensin system genes between strains may result from epigenetic mechanisms such as genome imprinting of these genes or of another gene that functions as a common regulator of renin and angiotensinogen.

The renin-angiotensin system, a complex biological system which is well known in the regulation of blood pressure has indeed multiple interaction with other regulatory system. Recently, several findings have also pointed to a possible involvement of this system in male reproductive function. High amounts of angiotensin converting enzyme (ACE), the main regulatory enzyme of this system, do not only occure within the human lung and kidney, but also in the male genital tract. In man, ACE occurs in two structurally dissimilar isoenzymes, a testicular and a serum form. Testicular ACE represents the C-terminal half of the lung enzyme with a molecular mass of 80 kDa and 701 amino acid residues. Testicular ACE is the product of a testis specific in RNA and is hormonally regulated depending on androgen. While ACE has been completely Characterized biochemically, its biological role is still unknown. In the rat, the highest ACE activities are found in the restis and epididymis. Increasing concentrations are observed from the caput to the cauda epidymis. However, differences seem to exist among various species, with highest ACE level in the mous testis and epididymis, lowest level in buffallo and rabbit. The observed gradient of ACE concentrations within the epididymis indicates that ACE may play a certain role in sperm maturation. Testicular ACE seems to be associated with membranes of spermatocytes. Studies of cattle semen demonstrtated that ACE is released from spermatozoa during incubation in capacitation medium.

A unique aspect of the circulating renin-angiotensin system and the many independent tissue renin-angiotensin systems is their interactions at multiple levels with reproduction. These interactions, which have received relatively little attention, include effects of estrogens and possibly androgens on hepatic and renal angiotensinogen mRNA; effects of androgens on the Ren-2 gene and salivary renin in mice; the prorenin surge that occurs with but outlasts the LH surge during the menstrual cycle; the inhibitory effects of estrogens on thirst and water intake; the tissue renin-angiotensin systems in the brain, the anterior pituitary, and the ovaries and testes, that is, in all the components of the hypothalamo-pituitary-gonadal axis; the presence of some components of the renin-angiotensin system in the uterus and the fetoplacental unit; and the possible relation of renin and angiotensin to ovulation and fetal well-being. These interactions are described and their significance considered in this short review.

Scientific concern in studies on male reproduction has been mostly centered on understanding the complex regulation of androgen production, spermatogenesis and the maturation of sperm. Each of these areas has been extensively reviewed by Huhtaniemi and Toppari, Weinbauer and Nieschlag, Jegou and Pinau and by Cooper elsewhere in this volume. In these processes, the cardinal role played by the hypophyseal gonadotropins remains indisputable. At the same time, however, the importance of various locally active autocrine and/or paracrine regulatory factors can not be overlooked. While the list of such factors keeps on growing forever, tissue prorenin-renin-angiotensin system (PRAS) has received considerable attention in this respect during the recent years. In the search for a role of PRAS in reproduction, most of the scientific attention so far has been focused on its role in the regulation of ovarian function. This becomes obvious from the number of major reviews that have been published so far in this area and the most recent ones include those by Pepperell et al. (1993) and Nielsen et al. (elsewhere in this volume). Supported by a large number of scientific contributions from several laboratories worldwide, ovarian PRAS has become established as an important component of intraovarian regulatory mechanisms. The involvement of PRAS in the regulation of follicular atresia (Mukhopadhyay et al., 1991) and the process of ovulation (Andrade-Gordon et al., 1991) appears to be certain although mechanistic aspects remain to be clarified (Mukhopadhyay, 1994). In contrast, the role of PRAS in male reproduction has attracted relatively less attention, although the presence of renin was demonstrated in the testis long before it was shown in the ovary (see below).

Summary OBJECTIVES We have reported that 19-hydroxyandrostenedione (19-OH-A-dione) functions as an amplifier of the sodium-retaining and hypertensive action of aldosterone. We therefore measured 19-hydroxyandrostenedione in hypertensive patients. PATIENTS AND MEASUREMENTS We studied 53 normal male control subjects and 63 male patients with essential hypertension (48 patients with normal renin essential hypertension and 15 patients with high renin essential hypertension). Plasma 19-OH-A-dione levels were measured by RIA. RESULTS Plasma 19-OH-A-dione concentrations in control subjects and patients with normal and high renin essential hypertension were 115 ± 46 (meaniSD), 112 ± 49 and 201 ± 79 pmoI/I, respectively. Patients with high renin essential hypertension showed significantly higher 19-OH-A-dione concentrations than did control subjects. The evaluation of the correlation between plasma 19-OH-A-dione concentrations and plasma renin activity revealed that plasma 19-OH-A-dione concentrations in hypertensive subjects rose gradually with an increase in plasma renin activity. Therefore, a significant correlation was found between plasma renin activity and plasma 19-OH-A-dione (r= 0 586, P < 0001). In contrast, in control subjects, no significant correlation was found between plasma renin activity and plasma 19-OH-A-dione (r=0 059, P

Gonadectomy induced a significant retardation of systolic blood pressure (BP) in male and female spontaneously hypertensive rats (SHR). Captopril (5 mg/kg, i.p.), an angiotensin converting enzyme (ACE) inhibitor, significantly decreased BP in all groups, except that the antihypertensive action was significantly inhibited by gonadectomy in both sexes. The plasma ACE activity was increased in orchiectomized males, but this effect did not appear in females. Neither plasma renin activity nor its concentration were changed by gonadectomy in either sex. Aorta ACE activity was not changed by gonadectomy in either sex, while the renin activity was increased only in gonadectomized females. Diencephalon ACE activity was not changed by gonadectomy in either sex, but the renin activity was decreased in these groups. These results suggested that the decrease of BP by gonadectomy in both sexes SHR was closely related to the decrease of renin activity in diencephalon by androgen deprivation with gonadectomy.

Basal activity of submaxillary gland (SMG) renin is high in female mice that carry the Rnrs allele and is induced to higher levels by treatment with dihydrotestosterone (DHT). To determine whether the difference in basal activity between high (Rnrs/Rnrs) and low (Rnrb/Rnrb) strains is due to enhanced sensitivity of Rnrs/Rnrs strains to endogenous androgen, we first studied the effect of several types of endocrine ablation on SMG renin in young female mice, and second, we removed normal androgen receptor protein by introducing the X-linked Tfm gene. Adrenalectomy with or without castration had no effect on basal SMG renin; hypophysectomy decreased basal renin activity 400-fold but did not abolish responsiveness to DHT. Loss of androgen receptor did not affect basal renin activity but did prevent enhancement by DHT. Basal and induced renin activities in L.AKR(Alll)/Cy, a congenic strain homozygous for Rnrs introduced from AKR/J into the background of C57L/J, an Rnrb/Rnrb type strain, are intermediate between levels observed in the original strains. We conclude that (1) the basal level of SMG renin is regulated directly or indirectly by some pituitary hormone(s) but not by androgen, (2) androgen induction of renin activity requires a normal androgen receptor, and (3) major gene(s) that regulate basal as well as induced SMG renin are in a circumscribed region of chromosome 1.

In mature outbred Swiss male mice, submandibular gland renin enzyme activity is 4- and 10-fold higher than in glands of prepubescent males and mature females, respectively. Levels of translatable renin mRNA have been studied in mouse submandibular gland during postnatal development and following administration of testosterone. The [35S]methionine-labeled cell-free translation products directed by male glandular mRNA contain a 47 +/- 2kd renin precursor that is not detected in products coded by prepubescent male or female gland mRNA. This cell-free synthesized precursor is detected immunochemically only in the translation products of gland mRNA from males of 33 days or older and from females receiving testosterone administration, a pattern consistent with the measurements of renin enzyme activity. This increase in biologically active renin mRNA is a selective one, since unfractionated male and female mRNAs have similar overall nucleotide sequence complexity corresponding to 1% of mouse single copy DNA. The cDNA transcribed from male gland mRNA reacts 5- and 10-fold faster with the template mRNA than with female or prepubescent male gland mRNA, respectively, which indicates that the male gland contains abundant nucleotide sequences that exist at low concentration in the female or prepubescent male. Selective hybrid arrested translation confirms that the levels of renin mRNA are lower in the glands of prepubescent males than in those of the mature males. These data indicate that the regulation of renin enzymatic activity by androgens is mediated by an increase in the levels of translatable renin mRNA both during postnatal development and after testosterone administration.

1. The plasma concentration of inactive renin was two-to three-fold higher in male than in female mice independently of whether mice of strains with low (BALB/c) or high (Theiller) content of active renin in the submandibular salivary glands were studied. 2. Removal of the submandibular glands did not affect the high plasma concentration of inactive renin in male mice. 3. Inactive plasma renin decreased over several days after castration of normal and sialoadenectomized male mice to the same levels as those found in normal female mice. 4. Treatment of these castrated male mice with testosterone increased and normalized inactive plasma renin independently of whether the submandibular glands had been previously removed or not. 5. Testosterone treatment of sialoadenectomized female mice increased inactive renin to the same levels as those found in normal male mice. 6. Our findings suggest that the sex difference in inactive plasma renin in mice may be explained by an increased secretion of inactive renin in male mice stimulated by androgens. 7. Since we have recently found that inactive plasma renin in male mice is mainly of renal origin, this increased secretion is most likely located to the kidneys.

Renin activity (EC 3.4.99.19) was measured in submaxillary gland extracts from four sets of recombinant inbred mouse strains. Recombination between Rnr, a gene that mediates the susceptibility of submaxillary gland renin to induction by androgen, and Dip-1, a chromosome 1 marker, was found in only 1 of 51 recombinant inbred strains, indicating that the two genes are closely linked on chromosome 1. Renin activity in androgen-treated female mice of all recombinant inbred strains resembled that of one or the other progenitor strains, as expected if a single gene is responsible. Documentation that a single gene can have major effects on renin in the submaxillary gland of the mouse implies that single gene differences might explain known variations in renin in other species.

Renal angiotensinogen (ang-n) mRNA concentration in the male WKY rat increases significantly during puberty. Furthermore, renal angiotensinogen mRNA level in the adult female WKY rat is considerably lower than in the male. The present study investigates the role of androgen in differential renal ang-n mRNA expression. Northern and slot blot analyses with alpha-32P labeled ang-n cDNA (pRang 3) demonstrated that castration lowered ang-n mRNA levels in the male kidney by greater than or equal to 60% compared with control, suggesting that androgen may be involved with renal ang-n gene regulation. Moreover, male WKY rats castrated as weanlings and normal adult female WKY rats each implanted with testosterone displayed significant (P less than 0.05) increases in renal ang-n mRNA levels. Our observations, taken together with previous reports that androgen influences proximal tubule morphology and the tubular expression of transport proteins (e.g., Na+/H+ antiporter), may have important physiological implications for understanding the relationship between androgen and angiotensin in the regulation of tubular function.