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TRANSLATIONAL PHYSIOLOGY

Brief exposure to exogenous testosterone increases death signaling and adversely affects myocardial function after ischemia

Departments of ¹Surgery, ²Cellular and Integrative Physiology, and the ³Center for Immunobiology, Indiana University School of Medicine, Indianapolis, Indiana

Submitted 29 November 2005 ; accepted in final form 17 January 2006

ABSTRACT

Chronic endogenous testosterone exposure adversely affects proinflammatory and proapoptotic signaling after ischemia/reperfusion; however, it remains unknown whether a single acute testosterone exposure is equally detrimental. We hypothesized that acute exogenous testosterone infusion before ischemia would worsen myocardial functional recovery, increase the activation of MAPKs and caspase-3, and increase myocardial proinflammatory cytokine production. To study this, isolated-perfused rat hearts (Langendorff) from adult females and castrated males were subjected to 25-min ischemia and 40-min reperfusion with and without acute testosterone infusion (17-hydroxy-4-androstenone, 10 ng·ml^–1·min^–1) before ischemia. Myocardial contractile function was continuously recorded. After ischemia/reperfusion, hearts were assessed for levels of testosterone (ELISA), expression of proinflammatory cytokines (ELISA), and activation of MAPKs and caspase-3 (Western blot analysis). Data were analyzed with two-way ANOVA or Student’s t-test; P < 0.05 was statistically significant. All indices of postischemic functional recovery were decreased with acute exogenous testosterone compared with the untreated groups. Acute testosterone infusion increased activation of MAPKs and caspase-3 following ischemia/reperfusion. However, there were no significant differences in the myocardial proinflammatory cytokine production after brief testosterone infusion. A single acute exposure to exogenous testosterone before ischemia worsens myocardial functional recovery and increases activation of MAPKs and caspase-3. These findings confirm the deleterious effects of testosterone on myocardium, elucidate the nongenomic mechanistic pathways of testosterone, and may have important clinical implications for patients who have acute exposure to exogenous testosterone.

myocardial infarction; sex hormones; inflammation

It is widely recognized that steroid hormones bind to intracellular receptors and modulate transcription and protein synthesis, triggering genomic events responsible for physiological effects (6). However, very rapid effects of steroids have also been revealed that are clearly incompatible with the genomic model (33, 47). Recent investigations suggest that testosterone can exert rapid, nongenomic effects (7, 29, 46). No study has focused on the nongenomic effects of acute testosterone exposure on myocardium after I/R. Because of these discrepancies between genomic and nongenomic effects of steroids and androgens, it is important to elucidate the mechanistic pathways of testosterone in myocardium subjected to I/R.

Therefore, on the basis of the negative effect of chronic endogenous testosterone, we hypothesized that exogenous acute testosterone infusion (ATI) before ischemia may directly exert deleterious effects on myocardium not exposed to chronic testosterone (females and castrated males). The purposes of this study were to investigate the effect of acute direct exogenous testosterone on postischemic: 1) myocardial function, 2) proinflammatory cytokine production and MAPK activation, and 3) pro- and antiapoptotic signaling.

MATERIALS AND METHODS

Animals. Normal female and male (280–300 g, 9–10 wk) Sprague-Dawley rats (Harlan, Indianapolis, IN) were fed a standard diet and acclimated in a quiet quarantine room for 2 wk before the experiments. The animal protocol was reviewed and approved by the Indiana Animal Care and Use Committee of Indiana University. All animals received humane care in compliance with the "Guide for the Care and Use of Laboratory Animals" (NIH publication No. 85-23, revised 1996).

Experimental groups. Rats were divided into four experimental groups: normal females (n = 9), females with acute testosterone infusion (ATI) before ischemia (n = 5), castrated males (n = 8), and castrated males with ATI before ischemia (n = 6). Acute testosterone infusion (17-hydroxy-4-androstenone) was administered at physiological levels, 10 ng·ml^–1·min^–1 x 5 min before ischemia. Male rats (100–125 g, 5–6 wk) received bilateral castration and were allowed at least 4 wk of recovery. That normal females were in the proestrus state was ensured by the performance of daily vaginal swabs. Isolated rat hearts in all groups were subjected to the same I/R protocol: 15-min equilibration period, 25 min of global ischemia (37°C), and 40 min of reperfusion.

Isolated heart preparation (Langendorff). Rats were anesthetized (pentobarbital sodium, 60 mg/kg ip) and heparinized (500 units ip), and then hearts were rapidly excised via median sternotomy and placed in 4°C Krebs-Henseleit (KH) solution. The aorta was cannulated, and the heart was retrograde perfused in the isolated, isovolumetric Langendorff mode (70 mmHg) with KH solution (in mM: 11 dextrose, 110 NaCl, 1.2 CaCl₂, 4.7 KCl, 20.8 NaHCO₃, 1.18 KHPO₄, 1.17 MgSO₄) at 37°C. The KH solution was bubbled with 95% O₂-5% CO₂ (Medipure) to achieve a PO₂ of 450–460 mmHg, PCO₂ 39–41 mmHg, and pH 7.39 to 7.41. Total ischemic time was less than 45 s. The perfusion buffer was continuously filtered through a 0.45-µm filter to remove particulates. A pulmonary arteriotomy and left atrial resection were performed before insertion of a water-filled latex balloon through the left atrium into the left ventricle. The preload volume (balloon volume) was held constant during the entire experiment to allow for continuous recording of the left ventricular developed pressure (LVDP). The balloon was adjusted to a mean left ventricular end-diastolic pressure (LVEDP) of 8 mmHg (range 6–10 mmHg) during the initial equilibration. Pacing wires were fixed to the right atrium and left ventricle, and hearts were paced at 6 Hz, 3 V, 2 ms (350 beats/min) throughout perfusion. A three-way stopcock above the aortic root was used to create global ischemia during which the heart was placed in a 37°C degassed organ bath. Coronary flow was measured by collecting pulmonary artery effluent. Data were continuously recorded using a PowerLab 8 preamplifier/digitizer (AD Instruments, Milford, MA) and an Apple G4 PowerPC computer (Apple Computer, Cupertino, CA). The maximal positive and negative value of the first derivative of pressure (+dP/dt and –dP/dt) were calculated using PowerLab software. After reperfusion, the heart was removed from the apparatus, immediately sectioned, and snap frozen in liquid nitrogen.

Myocardial proinflammatory cytokine expression, and testosterone expression. Heart tissue was homogenized in cold buffer containing (in mM) 20 Tris (pH 7.5), 150 NaCl, 1 EDTA, 1 EGTA, 2.5 sodium pyrophosphate, 1 -glycerophosphate, 1 Na₃VO₄, 1 PMSF, plus 1 µg/ml leupeptin and 1% Triton X-100, and centrifuged at 12,000 rpm for 5 min (Eppendorf Centrifuge 5417R, Westbury, NY). Myocardial TNF-, IL-1, IL-6, and testosterone in the cardiac tissue were determined by ELISA using a commercially available ELISA kit (R&D Systems, Minneapolis, MN). ELISA was performed according to the manufacturer’s instructions. All samples and standards were measured in duplicate.

Western blot analysis. Western blot analysis was performed to measure MAPK and apoptosis-related proteins. Heart tissue was homogenized in cold buffer containing (in mM) 20 Tris (pH 7.5), 150 NaCl, 1 EDTA, 1 EGTA, 2.5 sodium pyrophosphate, 1 -glycerophosphate, 1 Na₃VO₄, 1 PMSF, plus 1 µg/ml leupeptin and 1% Triton X-100, and centrifuged at 12,000 rpm for 5 min (Eppendorf Centrifuge 5417R). The protein extracts (30 µg/lane) were subjected to electrophoresis on a 12% Tris·HCl gel (Bio-Rad, Hercules, CA) and transferred to a nitrocellulose membrane that was stained by Naphthol Blue-Black to confirm equal protein loading. The membranes were incubated in 5% dry milk for 1 h and then incubated with the following primary antibodies: p38 MAPK antibody, phosphor-p38 MAPK (Thr180/Tyr182) antibody, SAPK/JNK antibody, phosphor-SAPK/JNK (Thr183/Tyr185) antibody, p44/42 MAPK antibody, phosphor-p44/42 MAPK (Thr202/Tyr204) antibody (Cell Signaling Technology, Beverly, MA), caspase-3 (H-277) antibody (Santa Cruz Biotechnology, Santa Cruz, CA), Bcl-2 (Ab-4) antibody, and GAPDH antibody (Oncogene Research Products, San Diego, CA). Subsequently, the membranes were incubated with horseradish peroxidase-conjugated goat anti-rabbit or anti-mouse IgG secondary antibody. Detection was performed using supersignal west pico stable peroxide solution (Pierce, Rockford, IL). Films were scanned using an Epson Perfection 3200 Scanner (Epson America, Long Beach, CA), and band density was analyzed using ImageJ software (National Institutes of Health). Spots of dirty background were digitally erased.

Presentation of data and statistical analysis. All reported values are means ± SE (n = 5–9/group). Data were compared using two-way ANOVA with the post hoc Bonferroni test or Student’s t-test (female control vs. female with ATI and castrated male control vs. castrated male with ATI). A two-tailed P < 0.05 was considered statistically significant. Representative gels are shown with all lanes/samples from the same gel for each respective figure.

RESULTS

Testosterone levels following I/R. Testosterone levels following I/R assessed via ELISA were significantly greater in females (170.9 ± 21.2 pg/mg) and castrated males (118.6 ± 9.7 pg/mg) with ATI compared with females and castrated males without ATI (38.3 ± 9.7 and 54.2 ± 16.9 pg/mg), respectively (Fig. 1). There were no significant differences between females with ATI and castrated males with ATI.

View larger version (11K): [in this window] [in a new window]   Fig. 1. Myocardial testosterone levels after ischemia-reperfusion (I/R). Females (F) with acute testosterone infusion (ATI; F I/R + ATI) and castrated males (CM) with ATI (CM I/R + ATI) had significantly higher testosterone levels than females (F I/R) and castrated males (CM I/R) without ATI. There were no significant differences between females with ATI and castrated males with ATI. Results are means ± SE, *P < 0.05 females with ATI vs. females, P < 0.05 castrated males with ATI vs. castrated males.

View larger version (25K): [in this window] [in a new window]   Fig. 2. Changes in myocardial function following I/R in normal females, females with ATI, castrated males, and castrated males with ATI. A: left ventricular developed pressure (LVD; %equilibration). End reperfusion LVDP %equilibration was significantly higher in females and castrated males than in females and castrated males with ATI, respectively. B: left ventricular end diastolic pressure. C: first derivative of pressure (+dP/dt) maximum; D: –dP/dt. Results are means ± SE, *P < 0.05 females with ATI vs. normal females, P < 0.05 castrated males with ATI vs. castrated males at the corresponding time points.

Maximum positive and negative dP/dt were impaired at the start of reperfusion. Female hearts and castrated male hearts exposed to ATI demonstrated more depression of +dP/dt and elevation of –dP/dt compared with castrated males and normal females (Fig. 2, C and D).

Myocardial MAPK signaling pathway following I/R. The myocardial activation of phosphorylated p38 (active), nonphosphorylated p38 (total) MAPK, phosphorylated SAPK/JNK, nonphosphorylated SAPK/JNK, phosphorylated p44/42 MAPK, and nonphosphorylated p44/42 MAPK were assessed by Western blot analysis (Fig. 3). The phosphorylated forms of p38 MAPK and JNK were increased in females and castrated males with ATI compared with females and castrated males without intervention. Total p38 MAPK, total JNK, active p44/42 MAPK, and total p44/42 MAPK were equivalent in females, females with ATI, castrated males, and castrated males with ATI following I/R.

View larger version (60K): [in this window] [in a new window]   Fig. 3. I/R induced myocardial phosphorylation of p38 MAPK, JNK, and p44/42 (ERK). The expression of activated p38 MAPK and JNK signaling after I/R injury in female (F I/R + ATI) and castrated male hearts (CM I/R + ATI) with ATI was greater than females (F I/R) and castrated males (CM I/R) without ATI. No significant difference in expression among experimental groups was observed in total p38 MAPK, total JNK, and both activated and total p44/42. Shown are representative immunoblots. Row 1: phosphorylated (activated) p38 MAPK. Row 2: total p38 MAPK. Row 3: phosphorylated JNK. Row 4: total JNK. Row 5: phosphorylated p44/42 MAPK. Row 6: total p44/42 MAPK. All samples were on the same membrane.

View larger version (18K): [in this window] [in a new window]   Fig. 4. Effect of acute testosterone on myocardial TNF-, IL-1, and IL-6 production (in pg/mg) after I/R. Cardiac TNF- (A), IL-6 (B) and IL-1 (C) production was not significantly different between females (F I/R + ATI) and castrated males (CM I/R + ATI) with ATI compared with those (F I/R, CM I/R) without ATI. Results are means ± SE.

View larger version (50K): [in this window] [in a new window]   Fig. 5. Myocardial expression of proapoptotic and antiapoptotic enzymes in females (F I/R), females with ATI (F I/R + ATI), castrated males (CM I/R), and castrated males with ATI (CM I/R + ATI) after I/R. Shown are representative immunoblots. A: active caspase-3 levels were increased in female hearts with ATI compared with normal females. Castrated males with and without ATI had no significant difference. All samples were on the same membrane. B: Bcl-2 expression on immunoblot was decreased in castrated males with ATI compared with castrated males without intervention. No difference in Bcl-2 expression was observed in females with and without ATI. All samples were on the same membrane.

The results of this study clearly demonstrate that after I/R, in hearts devoid of chronic testosterone exposure, a single dose of exogenous testosterone 1) depresses myocardial functional recovery, 2) increases activation of p38 MAPK and JNK, 3) increases expression of apoptotic protein caspase 3, and 4) decreases expression of antiapoptotic protein Bcl-2.

Testosterone may play an important role in the contractile dysfunction induced by I/R injury for several reasons. Functional androgen receptors are present in isolated cardiac myocytes (24, 25), and the heart can accumulate testosterone at higher concentrations than other androgen target organs (21). Acute exogenous testosterone produces a hypertrophic response in the heart by acting directly on androgen receptors in cardiac muscle cells (24, 34). This cardiac hypertrophy may result in an increase in ventricular stiffness (42), which reduces myocardial contractility. Indeed, the results of this study confirm the acute deleterious effects of testosterone on myocardial functional recovery after I/R; ATI caused statistically significant depression of %recovery –dP/dt (a measure of compliance) in both females and castrated males. However, it remains unclear through which mechanisms testosterone exerts its myocardial depression following I/R.

Although testosterone traditionally mediates its effects via nuclear transcription, recent investigations indicate that testosterone can also exert rapid effects (12, 14, 46). In particular, recent investigations have elucidated that the androgen receptor is able to activate the MAPK family through a mechanism independent of their transcriptional activity (20, 31). Two members of the MAPK family, p38 MAPK and JNK, have been identified as signaling enzymes of myocardial inflammation (8, 15). I/R injury results in activation of myocardial p38 MAPK and JNK (11, 23, 39), whereas p38 MAPK and JNK inhibition leads to improved myocardial function following I/R (22, 36). Gender differences exist in the activation of p38 MAPK (3). This study demonstrates that exogenous ATI in females and castrated males decreased myocardial contractility and increased both activated p38 MAPK and activated JNK following I/R. Therefore, it is possible that acute exogenous testosterone adversely affects myocardial function via androgen receptor activation of nontranscriptional mechanistic pathways, such as MAPK inflammatory signaling.

Ultimately, depression of myocardial function following I/R and loss of cardiomyocytes result from myocardial apoptosis. Apoptosis may be mediated by either the extrinsic death receptor signaling pathway or the intrinsic mitochondrial control pathway (19). Caspases play a crucial role in each of these pathways. The activation of caspase-3 has been observed in response to hypoxia or ischemia (35). Gender differences exist in the caspase cascades leading to apoptosis. Clinically, myocyte apoptosis in heart failure is increased in men compared with women (13). In isolated rat hearts, increased activation of proapoptotic caspase-3 after I/R was associated with chronic endogenous testosterone exposure (45). In vitro studies also found increased apoptosis in rat myocytes exposed to acute testosterone (48, 52). Similarly, in this study, we observed increased activation of caspase-3 in females with ATI compared with females without ATI following I/R. In addition, we also found a significant decrease in activation of Bcl-2, an antiapoptotic signaling enzyme, in castrated males with ATI compared with castrated males without ATI. Whether these effects are mediated by nongenomic or genomic effects remains uncertain. Nevertheless, elevated caspase-3 levels and decreased Bcl-2 levels in hearts subjected to endogenous and exogenous testosterone imply that the detrimental effect of testosterone on myocardium may be induced by activation of proapoptotic signaling caspases and the downregulation of antiapoptotic signaling enzymes.

We found no significant difference in the myocardial production of TNF-, IL-1, and IL-6 in hearts with exogenous ATI compared with hearts without intervention. Other investigators have found divergent cytokine release when myocardia were exposed to estrogen and testosterone (1, 2, 10, 40, 49, 51). Previously, we found that endogenous testosterone exposure increased myocardial cytokine production and decreased postischemic cardiac function, suggesting that endogenous testosterone exerts a deleterious effect on myocardium via increased myocardial inflammation (45). The discrepancy in myocardial cytokine production between chronic endogenous testosterone and acute exogenous testosterone exposure may reflect the innate difference between transcriptional effects (chronic testosterone) and acute nongenomic effects (acute testosterone). In this study, a single brief exposure to testosterone was administered immediately before ischemia; previously, rats were testosterone depleted (castrated) or testosterone was blocked for 4 wk before I/R (45). Perhaps the lack of time for adaptation or nuclear transcription in acute exogenous testosterone infusion precluded myocardial cytokine production. This discrepancy in cytokine production between chronic and acute testosterone exposure intimates that testosterone may exert its deleterious effects on myocardium via different genomic and nongenomic pathways depending on the temporal application.

There still remains a great deal of controversy over the role of gender and injury. This study confirms the deleterious effects of testosterone on myocardium after acute injury. This investigation also lends insight into the complex mechanistic genomic and nongenomic pathways of testosterone action. These findings may have important clinical implications for patients who have acute exposure to exogenous testosterone. This may also help explain the variation in clinical outcomes between males and females after myocardial infarction. Perhaps modification of testosterone-dependent mechanisms associated with I/R will alter the myocardial response to ischemia. Additional investigations into testosterone-dependent mechanisms and the resultant detrimental effects must be performed to gain a more complete understanding of gender and injury.

ACKNOWLEDGMENTS

This work was supported in part by National Institute of General Medical Science Grant R01-GM-070628 (to D. R. Meldrum), an American Heart Association Postdoctoral Fellowship (to M. Wang), the Clarian Values Fund (to D. R. Meldrum), the Showalter Trust (to D. R. Meldrum), and the Cryptic Masons Medical Research Foundation (to D. R. Meldrum and M. Wang).

FOOTNOTES

Address for reprint requests and other correspondence: D. R. Meldrum, 545 Barnhill Dr., Emerson Hall 215, Indianapolis, IN 46202 (e-mail: dmeldrum{at}iupui.edu)

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

^* P. R. Crisostomo and M. Wang contributed equally to this work.

REFERENCES

1. Angele MK, Ayala A, Monfils BA, Cioffi WG, Bland KI, and Chaudry IH. Testosterone and/or low estradiol: normally required but harmful immunologically for males after trauma-hemorrhage. J Trauma 44: 78–85, 1998.[ISI][Medline]
2. Angele MK, Knoferl MW, Schwacha MG, Ayala A, Cioffi WG, Bland KI, and Chaudry IH. Sex steroids regulate pro- and anti-inflammatory cytokine release by macrophages after trauma-hemorrhage. Am J Physiol Cell Physiol 277: C35–C42, 1999.[Abstract/Free Full Text]
3. Angele MK, Nitsch S, Knoferl MW, Ayala A, Angele P, Schildberg FW, Jauch KW, and Chaudry IH. Sex-specific p38 MAP kinase activation following trauma-hemorrhage: involvement of testosterone and estradiol. Am J Physiol Endocrinol Metab 285: E189–E196, 2003.[Abstract/Free Full Text]
4. Angele MK, Schwacha MG, Ayala A, and Chaudry IH. Effect of gender and sex hormones on immune responses following shock. Shock 14: 81–90, 2000.[ISI][Medline]
5. Baker L, Meldrum KK, Wang M, Sankula R, Vanam R, Raiesdana A, Tsai BM, Hile K, Brown JW, and Meldrum DR. The role of estrogen in cardiovascular disease. J Surg Res 115: 325–344, 2003.[CrossRef][ISI][Medline]
6. Beato M and Klug J. Steroid hormone receptors: an update. Hum Reprod Update 6: 225–236, 2000.[Abstract/Free Full Text]
7. Ceballos G, Figueroa L, Rubio I, Gallo G, Garcia A, Martinez A, Yanez R, Perez J, Morato T, and Chamorro G. Acute and nongenomic effects of testosterone on isolated and perfused rat heart. J Cardiovasc Pharmacol 33: 691–697, 1999.[CrossRef][ISI][Medline]
8. Cobb MH. MAP kinase pathways. Prog Biophys Mol Biol 71: 479–500, 1999.[CrossRef][ISI][Medline]
9. Culig Z, Hobisch A, Cronauer MV, Hittmair A, Radmayr C, Bartsch G, and Klocker H. Activation of the androgen receptor by polypeptide growth factors and cellular regulators. World J Urol 13: 285–289, 1995.[ISI][Medline]
10. Dienstknecht T, Schwacha MG, Kang SC, Rue LW, Bland KI, and Chaudry IH. Sex steroid-mediated regulation of macrophage/monocyte function in a two-hit model of trauma-hemorrhage and sepsis. Cytokine 25: 110–118, 2004.[CrossRef][ISI][Medline]
11. Dougherty CJ, Kubasiak LA, Prentice H, Andreka P, Bishopric NH, and Webster KA. Activation of c-Jun N-terminal kinase promotes survival of cardiac myocytes after oxidative stress. Biochem J 362: 561–571, 2002.[CrossRef][ISI][Medline]
12. Falkenstein E, Tillmann HC, Christ M, Feuring M, and Wehling M. Multiple actions of steroid hormones—a focus on rapid, nongenomic effects. Pharmacol Rev 52: 513–556, 2000.[Abstract/Free Full Text]
13. Guerra S, Leri A, Wang X, Finato N, Di Loreto C, Beltrami CA, Kajstura J, and Anversa P. Myocyte death in the failing human heart is gender dependent. Circ Res 85: 856–866, 1999.[Abstract/Free Full Text]
14. Heinlein CA and Chang C. The roles of androgen receptors and androgen-binding proteins in nongenomic androgen actions. Mol Endocrinol 16: 2181–2187, 2002.[Abstract/Free Full Text]
15. Khan TA, Bianchi C, Ruel M, Voisine P, and Sellke FW. Mitogen-activated protein kinase pathways and cardiac surgery. J Thorac Cardiovasc Surg 127: 806–811, 2004.[Abstract/Free Full Text]
16. Kher A, Meldrum KK, Wang M, Tsai BM, Pitcher JM, and Meldrum DR. Cellular and molecular mechanisms of sex differences in renal ischemia-reperfusion injury. Cardiovasc Res 67: 594–603, 2005.[Abstract/Free Full Text]
17. Kher A, Wang M, Tsai BM, Pitcher JM, Greenbaum ES, Nagy RD, Patel KM, Wairiuko GM, Markel TA, and Meldrum DR. Sex differences in the myocardial inflammatory response to acute injury. Shock 23: 1–10, 2005.[ISI][Medline]
18. Knoferl MW, Angele MK, Schwacha MG, Anantha Samy TS, Bland KI, and Chaudry IH. Immunoprotection in proestrus females following trauma-hemorrhage: the pivotal role of estrogen receptors. Cell Immunol 222: 27–34, 2003.[CrossRef][ISI][Medline]
19. Konopleva M, Zhao S, Xie Z, Segall H, Younes A, Claxton DF, Estrov Z, Kornblau SM, and Andreeff Apoptosis M. Molecules and mechanisms. Adv Exp Med Biol 457: 217–236, 1999.[ISI][Medline]
20. Kousteni S, Bellido T, Plotkin LI, O’Brien CA, Bodenner DL, Han L, Han K, DiGregorio GB, Katzenellenbogen JA, Katzenellenbogen BS, Roberson PK, Weinstein RS, Jilka RL, and Manolagas SC. Nongenotropic, sex-nonspecific signaling through the estrogen or androgen receptors: dissociation from transcriptional activity. Cell 104: 719–730, 2001.[ISI][Medline]
21. Krieg M, Smith K, and Bartsch W. Demonstration of a specific androgen receptor in rat heart muscle: relationship between binding, metabolism, and tissue levels of androgens. Endocrinology 103: 1686–1694, 1978.[ISI][Medline]
22. Li D, Williams V, Liu L, Chen H, Sawamura T, Antakli T, and Mehta JL. LOX-1 inhibition in myocardial ischemia-reperfusion injury: modulation of MMP-1 and inflammation. Am J Physiol Heart Circ Physiol 283: H1795–H1801, 2002.[Abstract/Free Full Text]
23. Liao P, Wang SQ, Wang S, Zheng M, Zhang SJ, Cheng H, Wang Y, and Xiao RP. p38 Mitogen-activated protein kinase mediates a negative inotropic effect in cardiac myocytes. Circ Res 90: 190–196, 2002.[Abstract/Free Full Text]
24. Marsh JD, Lehmann MH, Ritchie RH, Gwathmey JK, Green GE, and Schiebinger RJ. Androgen receptors mediate hypertrophy in cardiac myocytes. Circulation 98: 256–261, 1998.[Abstract/Free Full Text]
25. McGill HC Jr, Anselmo VC, Buchanan JM, and Sheridan PJ. The heart is a target organ for androgen. Science 207: 775–777, 1980.[Abstract/Free Full Text]
26. Melchert RB and Welder AA. Cardiovascular effects of androgenic-anabolic steroids. Med Sci Sports Exerc 27: 1252–1262, 1995.
27. Meldrum DR. Tumor necrosis factor in the heart. Am J Physiol Regul Integr Comp Physiol 274: R577–R595, 1998.[Abstract/Free Full Text]
28. Meldrum DR, Wang M, Tsai BM, Kher A, Pitcher JM, Brown JW, and Meldrum KK. Intracellular signaling mechanisms of sex hormones in acute myocardial inflammation and injury. Front Biosci 10: 1835–1867, 2005.[ISI][Medline]
29. Mendelsohn ME and Karas RH. Molecular and cellular basis of cardiovascular gender differences. Science 308: 1583–1587, 2005.[Abstract/Free Full Text]
30. Mendelsohn ME and Karas RH. The protective effects of estrogen on the cardiovascular system. N Engl J Med 340: 1801–1811, 1999.[Free Full Text]
31. Migliaccio A, Castoria G, Di Domenico M, de Falco A, Bilancio A, Lombardi M, Barone MV, Ametrano D, Zannini MS, Abbondanza C, and Auricchio F. Steroid-induced androgen receptor-oestradiol receptor beta-Src complex triggers prostate cancer cell proliferation. EMBO J 19: 5406–5417, 2000.[CrossRef][ISI][Medline]
32. Mizushima Y, Wang P, Jarrar D, Cioffi WG, Bland KI, and Chaudry IH. Estradiol administration after trauma-hemorrhage improves cardiovascular and hepatocellular functions in male animals. Ann Surg 232: 673–679, 2000.[CrossRef][ISI][Medline]
33. Morley P, Whitfield JF, Vanderhyden BC, Tsang BK, and Schwartz JL. A new, nongenomic estrogen action: the rapid release of intracellular calcium. Endocrinology 131: 1305–1312, 1992.[Abstract]
34. Nahrendorf M, Frantz S, Hu K, von zur Muhlen C, Tomaszewski M, Scheuermann H, Kaiser R, Jazbutyte V, Beer S, Bauer W, Neubauer S, Ertl G, Allolio B, and Callies F. Effect of testosterone on postmyocardial infarction remodeling and function. Cardiovasc Res 57: 370–378, 2003.[Abstract/Free Full Text]
35. O’Mahoney ME, Logue S, Szegezdi E, Stenson-Cox C, Fitzgerald U, and Samali A. Hypoxia and ischemia induce nuclear condensation and caspase activation in cardiomyocytes. Ann NY Acad Sci 1010: 728–732, 2003.[Free Full Text]
36. Pantos C, Malliopoulou V, Paizis I, Moraitis P, Mourouzis I, Tzeis S, Karamanoli E, Cokkinos DD, Carageorgiou H, Varonos D, and Cokkinos DV. Thyroid hormone and cardioprotection: study of p38 MAPK and JNKs during ischaemia and at reperfusion in isolated rat heart. Mol Cell Biochem 242: 173–180, 2003.[CrossRef][ISI][Medline]
37. Remmers DE, Cioffi WG, Bland KI, Wang P, Angele MK, and Chaudry IH. Testosterone: the crucial hormone responsible for depressing myocardial function in males after trauma-hemorrhage. Ann Surg 227: 790–799, 1998.[CrossRef][ISI][Medline]
38. Remmers DE, Wang P, Cioffi WG, Bland KI, and Chaudry IH. Testosterone receptor blockade after trauma-hemorrhage improves cardiac and hepatic functions in males. Am J Physiol Heart Circ Physiol 273: H2919–H2925, 1997.[Abstract/Free Full Text]
39. Salituro FG, Germann UA, Wilson KP, Bemis GW, Fox T, and Su MS. Inhibitors of p38 MAP kinase: therapeutic intervention in cytokine-mediated diseases. Curr Med Chem 6: 807–823, 1999.[ISI][Medline]
40. Schneider CP, Schwacha MG, Samy TS, Bland KI, and Chaudry IH. Androgen-mediated modulation of macrophage function after trauma-hemorrhage: central role of 5-dihydrotestosterone. J Appl Physiol 95: 104–112, 2003.[Abstract/Free Full Text]
41. Szalay L, Shimizu T, Suzuki T, Yu HP, Choudhry MA, Schwacha MG, Rue Iii LW, Bland KI, and Chaudry IH. Estradiol improves cardiac and hepatic function following trauma-hemorrhage: role of enhanced heat shock protein expression. Am J Physiol Regul Integr Comp Physiol 290: R812–R818, 2006.[Abstract/Free Full Text]
42. Trifunovic B, Norton GR, Duffield MJ, Avraam P, and Woodiwiss AJ. An androgenic steroid decreases left ventricular compliance in rats. Am J Physiol Heart Circ Physiol 268: H1096–H1105, 1995.[Abstract/Free Full Text]
43. Wang M, Baker L, Tsai BM, Meldrum KK, and Meldrum DR. Sex differences in the myocardial inflammatory response to ischemia/reperfusion injury. Am J Physiol Endocrinol Metab 288: E321–E326, 2005.[Abstract/Free Full Text]
44. Wang M, Tsai BM, Brown JW, and Meldrum DR. Gender differences in myocardial apoptotic signaling and recovery following acute injury (Abstract). Shock 21, Suppl 2: 23, 2004.
45. Wang M, Tsai BM, Kher A, Baker LB, Wairiuko GM, and Meldrum DR. Role of endogenous testosterone in myocardial proinflammatory and proapoptotic signaling after acute ischemia-reperfusion. Am J Physiol Heart Circ Physiol 288: H221–H226, 2005.[Abstract/Free Full Text]
46. Wehling M. Specific, nongenomic actions of steroid hormones. Annu Rev Physiol 59: 365–393, 1997.[CrossRef][ISI][Medline]
47. Wehling M, Bauer MM, Ulsenheimer A, Schneider M, Neylon CB, and Christ M. Nongenomic effects of aldosterone on intracellular pH in vascular smooth muscle cells. Biochem Biophys Res Commun 223: 181–186, 1996.[CrossRef][ISI][Medline]
48. Welder AA, Robertson JW, Fugate RD, and Melchert RB. Anabolic-androgenic steroid-induced toxicity in primary neonatal rat myocardial cell cultures. Toxicol Appl Pharmacol 133: 328–342, 1995.[CrossRef][ISI][Medline]
49. Wichmann MW, Ayala A, and Chaudry IH. Male sex steroids are responsible for depressing macrophage immune function after trauma-hemorrhage. Am J Physiol Cell Physiol 273: C1335–C1340, 1997.[Abstract/Free Full Text]
50. Wu FC and von Eckardstein A. Androgens and coronary artery disease. Endocr Rev 24: 183–217, 2003.[Abstract/Free Full Text]
51. Yang S, Zheng R, Hu S, Ma Y, Choudhry MA, Messina JL, Rue LW, 3rd Bland KI, and Chaudry IH. Mechanism of cardiac depression after trauma-hemorrhage: increased cardiomyocyte IL-6 and effect of sex steroids on IL-6 regulation and cardiac function. Am J Physiol Heart Circ Physiol 287: H2183–H2191, 2004.[Abstract/Free Full Text]
52. Zaugg M, Jamali NZ, Lucchinetti E, Xu W, Alam M, Shafiq SA, and Siddiqui MA. Anabolic-androgenic steroids induce apoptotic cell death in adult rat ventricular myocytes. J Cell Physiol 187: 90–95, 2001.[CrossRef][ISI][Medline]

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