白首乌C21甾体苷诱导肝癌细胞凋亡的作用及其机制

研究白首乌C₂₁甾体苷对肝癌实体瘤细胞的凋亡作用及其机制。建立肝癌实体型(Heps)小鼠移植性肿瘤模型，随机分为模型组和C₂₁甾体苷各用药组，连续灌胃，10 d后脱颈椎处死小鼠，进行抑瘤率计算，对肿瘤组织进行电镜下观察，采用免疫荧光(AO/EB)测定肿瘤细胞凋亡，免疫组化染色检测bcl-2基因的表达。C₂₁甾体苷(10，20和40 mg·kg^-1)对小鼠移植性肝癌Heps有抑制作用，3个剂量组的抑瘤率分别为34.79%，47.08%和50.23%。C₂₁甾体苷(10，20和40 mg·kg^-1)可增加肿瘤细胞的凋亡，电镜下可见凋亡的形态学改变，并出现凋亡小体；免疫组化结果显示，bcl-2基因的表达与模型组比较明显降低(p<0.01)，但不同于凋亡结果的是高剂量组的阳性面积表达比中剂量略高。降低高表达的bcl-2基因从而促进肝癌细胞的凋亡，可能是C₂₁甾体苷抗肝癌的机制之一。     

乌骨藤中C21甾体苷诱导SACC-83和SACC-LM细胞凋亡的作用及其机制研究

目的 研究乌骨藤提取物C₂₁甾体苷对唾液腺腺样囊性癌（salivary adenoid cystic carcinomacv,SACC）低侵袭细胞株（salivary adenoid cystic carcinoma-83,SACC-83）和肺高转移细胞株（SACC-LM）增殖抑制和诱导凋亡的作用及其机制。方法 用不同浓度（5,10,20,40,60,80,100 μmol·L^-1） C₂₁甾体苷处理SACC-83和SACC-LM细胞48 h后,MTT法检测细胞活力,并计算药物的IC₂₀和IC₅₀;细胞克隆形成实验检测细胞增殖能力;流式细胞术检测SACC-83及SACC-LM细胞凋亡情况;实时荧光定量PCR和Western blot检测SACC-83和SACC-LM细胞Bcl-2、Bax、caspase 3的mRNA和蛋白的表达。结果 不同浓度的C₂₁甾体苷降低SACC-83和SACC-LM细胞活力,抑制细胞增殖,并且作用于SACC-83细胞C₂₁甾体苷的IC₂₀浓度为7.49 μmol·L^-1,IC₅₀浓度为38.34 μmol·L^-1;作用于SACC-LM细胞的C₂₁甾体苷IC₂₀浓度为9.30 μmol·L^-1,IC₅₀浓度为46.04 μmol·L^-1;细胞克隆集落形成明显减少。C₂₁甾体苷IC₂₀浓度分别促进SACC-83及SACC-LM细胞凋亡,且随着给药时间延长,凋亡率增加,具有显著性差异（P<0.05,P<0.01）。经7.49,9.30 μmol·L^-1 C₂₁甾体苷分别处理SACC-83及SACC-LM细胞后,Bcl-2的mRNA及蛋白水平显著降低（P<0.01）,而Bax、Caspase 3的mRNA和蛋白水平显著升高（P<0.05）。结论 乌骨藤C₂₁甾体苷抑制SACC-83及SACC-LM细胞增殖、促进凋亡,其作用机制可能与调控Bcl-2、Bax和Caspase 3表达有关。     

RP-HPLC法测定重楼中甾体皂甙的含量

为寻找和合理利用植物资源及控制生药质量,用RP-HPLC法分离并测定了重楼中9种甾体皂甙,其中4种为偏诺皂甙元的糖甙,5种为薯芋皂甙元的糖甙。分析柱为C₈(4.6mm×250mm),乙腈—水(42∶58)为流动相,检测波长203nm,9种甾体皂甙峰与其相邻峰能达基线分离,且线性良好,γ=0.9996～0.9999,回收率97.1%～100.2%。本法简便、快速、灵敏。用此法对不同产地重楼中9种甾体皂甙类化合物进行了分析,结果提示不同产地重楼中各成分含量差异较大。     

通光散藤茎的C21甾体成分

为了研究通光散藤茎中的C₂₁甾体类成分，采用不同的色谱方法对通光散藤茎乙醇提取物进行分离纯化，并用波谱学的方法鉴定化合物的结构。从氯仿部位共分离得到8个C₂₁甾体类化合物，其结构分别被鉴定为11α-O-tigloyl-17β-tenacigenin B (1)、 17β-tenacigenin B (2)、 tenacigenoside A (3)、 11α-O-2-methylbutyryl-12β-O-acetyl tenacigenin B (4)、 tenacissoside H (5)、 marsdenoside A (6)、 tenacissoside G (7)和tenacissoside I (8)。其中化合物1为新化合物。     

华北白前中的C21甾体类化合物

从华北白前(Cynanchum hancockianum)干燥根的乙醇提取物中分离鉴定了6个C₂₁甾体化合物,其中白前甙元C(glaucogenin C,Ⅰ),白薇甙A(cynatratoside A,Ⅱ),白前甙元A(glaucogenin A,Ⅲ),脱水何拉得甙元(anhydrohirundigenin,Ⅳ)为已知化合物;华北白前甙元B(hancogenin B,Ⅴ),华北白前甙A(hancoside A,Ⅵ)为新化合物。提出了变型C₂₁甾体甙元质谱的裂解规律。药理实验发现化合物Ⅱ具有一定的抗肿瘤活性,化合物Ⅵ具有一定的抗内毒素作用。     

“抗孕-53”构型的测定

“抗孕-53”是一种新型甾体口服避孕药,存在二差向异构体,对它们一些相关化合物进行了核磁共振测定,根据C₂不同构型炔基磁各向异性对19-CH₃产生不同的屏蔽效应,导致了19-CH₃的特殊位移。比较炔基氢化前后19-CH₃化学位移变化情况,同时研究了不同构型的C₂-OH对19-CH₃的不同吡啶溶剂效应,分别推断二个异构体的构型,确证“抗孕-53”的炔基为α-取向。     

HPLC-ESI-ITMSn法鉴定麻黄碱及其大鼠体内主要代谢产物

目的建立快速灵敏的LC-ESI-ITMSⁿ分析检测麻黄碱及其大鼠体内代谢物的方法。方法以麻黄碱对照品对LC-ESI-ITMS²色谱及质谱条件进行了优化，分析总结其电喷雾质谱的一级电离规律和多级质谱裂解规律，以此作为麻黄碱大鼠体内代谢物分析鉴定的依据。健康大鼠空腹灌胃麻黄碱10 mg·kg^-1，收集0~48 h的尿样，经C₁₈小柱固相萃取分离纯化后，直接采用LC-ESI-ITMSⁿ方法对尿样进行测定。结果根据生物体内药物代谢转化规律及母体药物的色谱-质谱行为规律，在尿样中鉴定出3个第I相代谢产物，未发现第II相代谢产物。结论本方法灵敏、快速、选择性高、专属性好，可用于麻黄碱的代谢产物研究。     

双稠吡咯啶生物碱的研究 Ⅱ.瓜叶菊的生物碱

从瓜叶菊中分离得两个新的双稠吡咯啶生物碱,暫称为瓜叶菊碱甲及乙.甲素熔点为218—220℃(分解),分子式为C₁₈H₂₅NO₅;乙素熔点为200—202℃(分解),分子式C₁₈H₂₅NO₆。甲素及乙素的部分結构,分别暫定为(Ⅰ)及(Ⅱ)式所示。     

HPLC-MSn法鉴定葫芦巴碱及其在大鼠体内的主要代谢产物

目的建立快速灵敏的LC-MSⁿ检测葫芦巴碱及其在大鼠体内代谢物的分析方法。方法以葫芦巴碱对LC-MS²色谱及质谱条件进行优化，分析其电喷雾质谱的一级电离规律和多级质谱裂解规律，以此作为葫芦巴碱大鼠体内代谢物分析鉴定的依据。健康大鼠尾静脉注射8 mg·kg^-1葫芦巴碱，收集0～48 h的尿样，经C₁₈小柱固相萃取分离纯化后，直接采用LC-MSⁿ方法对尿样进行测定。结果根据生物体内药物代谢转化规律及母体药物的色谱-质谱行为规律，在尿样中鉴定出母药及其N-去甲基、N-去甲基环氧化产物，以及母药及其N-去甲基环氧化物的甘氨酸轭合物。结论本方法灵敏、快速、选择性高、专属性好，可用于葫芦巴碱的代谢产物研究。     

中药赤芍化学成分的研究

由中药赤芍(Paconia lactiflora Pall.)乙醇抽提物中分离得六种单纯成分。其中四种经鉴定证明为蔗糖、苯甲酸、β-谷甾醇和棕榈酸;另二种暂命名为赤芍甲素(C₁₇H₂₄O₃,沸点80℃/5毫米)和赤芍乙素(熔点256℃),并对其化学反应和红外光谱进行了研究。     

Over-the-counter anabolic steroids 4-androsten-3,17-dione; 4-androsten-3beta,17beta-diol; and 19-nor-4-androsten-3,17-dione: excretion studies in men.

Since the appearance of 4-androsten-3,17-dione (I) as a nutritional supplement in early 1997, we have frequently observed a characteristic deterioration of endogenous steroid profiles in athletes' urine in routine anabolic steroid testing in which concentrations of major endogenous urinary steroids and testosterone exceed normal. Human excretion studies are performed with I and newer, over-the-counter "supplements" 4-androsten-3beta,17beta-diol (II) and 19-nor-4-androsten-3,17-dione (III). Endogenous urinary steroids affected by I and II are androsterone, etiocholanolone, their hydroxylated derivatives 5alpha- and 5beta-androstan-3alpha,17beta-diols, testosterone, and epitestosterone. Their concentrations briefly increase by one to two orders of magnitude and return to normal 24 h after oral administration of I and II. The average male may test positive for testosterone because testosterone concentration rises faster than that of epitestosterone, causing the testosterone/epitestosterone (T/E) ratio to rise above the positive cutoff of 6:1. A remarkable distinction in excretion patterns was observed in eastern Asian men, for whom I and II did not affect urinary concentrations of testosterone and did not increase the T/E ratio. First-pass metabolism deactivates most of the orally administered drugs I and II, rapidly converting them into inactive androsterone and etiocholanolone. Drug II is a more effective testosterone booster because of its different metabolic pathway. After the use of III, a precursor of the potent anabolic nandrolone, high concentrations of norandrosterone and noretiocholanolone appear in urine, similar to nandrolone. These are detectable in urine for 7-10 days after a single oral dose of III (50 mg).     

Detection of nandrolone, testosterone, and their esters in rat and human hair samples.

Nandrolone and testosterone are anabolic androgenic steroids occasionally abused by athletes. A sensitive, specific, and reproducible gas chromatography-mass spectrometry method for the quantitative determination of nandrolone, testosterone, and their esters in hair has been developed. The limits of quantitation of this method, based on 20 mg of hair, were 50 pg/mg for nandrolone and testosterone, 100 pg/mg for testosterone acetate, and 200 pg/mg for nandrolone-decanoate. Nandrolone-d3 and testosterone-d3 were used as internal standards. This method has been applied to the analysis of these compounds incorporated into rat and human hair. Male Long-Evans rats were given nandrolone decanoate 60 mg/kg intraperitoneally (i.p.) once daily for 10 days over a time period of 14 days. Two of the three rats contained nandrolone in the pigmented hair collected at day 21 at a concentration of 63 and 76 pg/mg, respectively. No drug was found in the corresponding nonpigmented hair. The rat hair samples that tested positive for nandrolone contained also nandrolone decanoate in concentrations of 0.9 and 1.2 ng/mg, respectively. In a separate experiment rats were given testosterone acetate 10 mg/kg i.p. once daily for five days. No testosterone or testosterone acetate was detected in the rat hair samples. Hair specimens were also obtained from four self-reported steroid users. The hair of two subjects were determined to be positive for testosterone in concentrations of 54 and 81 pg/mg. These data demonstrate that it is possible to detect the steroids nandrolone, testosterone, and nandrolone decanoate in hair after systemic administration.     

Monitoring the endogenous steroid profile disruption in urine and blood upon nandrolone administration: An efficient and innovative strategy to screen for nandrolone abuse in entire male horses

Nandrolone (17β‐hydroxy‐4‐estren‐3‐one) is amongst the most misused endogenous steroid hormones in entire male horses. The detection of such a substance is challenging with regard to its endogenous presence. The current international threshold level for nandrolone misuse is based on the urinary concentration ratio of 5α‐estrane‐3β,17α‐diol (EAD) to 5(10)‐estrene‐3β,17α‐diol (EED). This ratio, however, can be influenced by a number of factors due to existing intra‐ and inter‐variability standing, respectively, for the variation occurring in endogenous steroids concentration levels in a single subject and the variation in those same concentration levels observed between different subjects. Targeting an efficient detection of nandrolone misuse in entire male horses, an analytical strategy was set up in order to profile a group of endogenous steroids in nandrolone‐treated and non‐treated equines. Experiment plasma and urine samples were steadily collected over more than three months from a stallion administered with nandrolone laurate (1 mg/kg). Control plasma and urine samples were collected monthly from seven non‐treated stallions over a one‐year period. A large panel of steroids of interest (n = 23) were extracted from equine urine and plasma samples using a C₁₈ cartridge. Following a methanolysis step, liquid‐liquid and solid‐phase extractions purifications were performed before derivatization and analysis on gas chromatography‐tandem mass spectrometry (GC‐MS/MS) for quantification. Statistical processing of the collected data permitted to establish statistical models capable of discriminating control samples from those collected during the three months following administration. Furthermore, these statistical models succeeded in predicting the compliance status of additional samples collected from racing horses. Copyright © 2013 John Wiley & Sons, Ltd.     

Testosterone and nandrolone sensitization of brain anteroventral area of third ventricle to hypertonic NaCl-induced sympathetic response

Androgenic steroids increase atherogenesis, thrombogenicity and endothelial dysfunction when administered in high doses, however their effects on NaCl sensitivity of the brain anteroventral area of the third ventricle (DeltaV3V) have not been explored. Sprague-Dawley male rats were anesthetized with sodium pentobarbital (40 mg/kg) and the femoral intra-arterial blood pressure and heart rate monitored through a strain-gauge blood pressure transducer and tachograph. DeltaV3V microinjections of (2 microl) 1.5 mol/l NaCl solution were done according to brain coordinates: AP = 7.0 mm, L = 1.0 mm, D = 7.5 mm through a 0.2-mm diameter stainless steel needle. The injection site was verified with 1.0 microl neutral red solution. Basal systolic blood pressure increased 37.6 and 39.6 mm Hg after testosterone (1 mg/kg/day for 20 days) and nandrolone (1 mg/kg/day for 20 days) treatment respectively; diastolic blood pressure also increased upon testosterone and nandrolone treatment in 36.4 and 53.1 mm Hg, respectively; basal heart rate did not change. Vasopressor response to 1.5 mol/l NaCl DeltaV3V microinjection was higher in testosterone-treated rats; systolic blood pressure increased 56.0 vs. 28.3 control mm Hg; diastolic blood pressure increased 54.0 vs. 25 control mm Hg. This hypertensive response was 29% longer lasting in testosterone compared to vehicle-treated rats. The same pattern of DeltaV3V sensitization to hypertonic NaCl was observed in nandrolone-treated rats. Blood lipid profile changed to a proatherogenic fashion upon testosterone and nandrolone long-term treatment; the plasma-free testosterone concentration increased from 4.9 +/- 0.9 to 36.0 +/-7.1 pg/ml with the same testosterone treatment schedule. In conclusion, long-term androgenic steroid treatment sensitizes the brain DeltaV3V region to hypertonic NaCl which in turn conducts into a sympathetic vasopressor and heart rate-stimulating action.     

Quantification and profiling of 19-norandrosterone and 19-noretiocholanolone in human urine after consumption of a nutritional supplement and norsteroids

Nandrolone is one of the synthetic anabolic steroids banned in sports and has been a popular substance abused by athletes in recent years. One of its major metabolites, 19-norandrosterone (19-NA), has been used as a determinant for drug violations in sports. Current reports regarding nandrolone-positive cases have been related to intake of some nandrolone-free nutritional supplements. The aim of this study was to learn whether if a nutritional supplement sold by over-the-counter (OTC) nutritional stores could yield the same metabolic products as that of nandrolone. If so, what is (are) the substance(s) that contributed to the nandrolone metabolites? To determine the content of an OTC nutritional supplement, a tablet was dissolved in methanol, followed by N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA)-trimethyliodosilane (TMIS) derivatization prior to gas chromatography-mass spectrometry (GC-MS) analysis. The collected urine samples underwent extraction, enzymatic hydrolysis, and derivatization before the analyses of GC-MS. The results showed that seven anabolic steroids were found as contaminants in the nutritional supplement, in addition to six that were listed in the ingredients by the manufacturer. We confirmed previous reports that administration of the OTC supplement could produce a positive urine test for nandrolone metabolites. Furthermore, the results from excretion studies showed that 19-NA and 19-noretiocholanolone (19-NE) were present in urine after consuming the nutritional supplement, nandrolone, 19-nor-4-androsten-3,17-dione, 19-nor-4-androsten-3beta,17beta-diol, and 19-nor-5-androsten-3beta,17beta-diol. The 19-NA concentrations in urine were generally higher than that of 19-NE (19-NA/19-NE ratio > 1.0) especially during the early stage of excretion, that is, before 6 h post-administration. After this period of time, the concentrations of 19-NA and 19-NE fluctuated and might even have reversed (19-NA/19-NE ratio < 1.0) in their ratio, that is, higher yield in 19-NE than that in 19-NA. On the basis of this study, we postulate that some doping violations of nandrolone could be attributed by indiscriminate administration of the OTC nutritional supplements that contained 19-norsteroids.     

Detrimental effects of anabolic steroids on human endothelial cells

The aim of this study is to investigate the effects in vitro induced by androgenic anabolic steroids (AAS) (testosterone, nandrolone, androstenedione, norandrostenedione, and norandrostenediol) used illicitly in sport competitions, on the proliferation ability, apoptosis and the intracellular calcium concentration ([Ca2+]i) in human umbilical vein endothelial cells (HUVECs), selected as a prototype of a biological target system whose structure and function can be affected by steroids. For this purpose, we evaluated the proliferation inhibition by cytotoxic assay expressed as the concentration of drug inducing a 50% decrease in growth (IC50). The IC50 was reached for testosterone at 100 microM, androstenedione at 375 microM, nandrolone at 9 microM, norandrostenedione at 500 microM. The IC50 value for norandrostenediol was not reached until a concentration of 6000 microM. The apoptotic effect was evaluated by flow cytometry at IC50 for each drug. We observed that testosterone induced 31% of apoptotic cells, norandrostenedione 25%, androstenedione 15% and nandrolone 18%. We have analyzed the effects of these drugs on [Ca2+]i both in the immediate and long-term continuous presence of each compound. Our data show a statistically significant increase of [Ca2+]i in the acute condition and in long-term treated cultures, suggesting that androgen steroids modulate intracellular levels of calcium independent of incubation time or compound identity. As a whole, this study demonstrates that AAS might alter endothelial homeostasis, predisposing to the early endothelial cell activation that is responsible for vascular complications observed frequently in AAS users.     

Determination of anabolic steroids in human urine by automated in-tube solid-phase microextraction coupled with liquid chromatography–mass spectrometry

A simple, rapid and sensitive method was developed for determining the presence of seven anabolic steroids (boldenone, nandrolone, testosterone, methyltestosterone, epiandrosterone, androsterone, and atnozolol) in human urine. Glucuronide-conjugates of these compounds were hydrolyzed with β-glucuronidase. The anabolic steroids were analyzed by on-line in-tube solid-phase microextraction (SPME) coupled with liquid chromatography–mass spectrometry (LC–MS). The steroids were separated within 14 min by high performance liquid chromatography using a Chromolith RP-18e column and 5 mM ammonium formate/methanol (35/65, v/v) as a mobile phase at a flow rate of 1.0 mL/min. Electrospray ionization conditions in the positive ion mode were optimized for the MS detection of these compounds. The optimum in-tube SPME conditions were 20 draw/eject cycles with a sample size of 40 μL using a Supel-Q PLOT capillary column for the extraction. The extracted compounds could be desorbed readily from the capillary column by flow of the mobile phase, and no carryover was observed. Using the in-tube SPME LC–MS with SIM mode detection, good linearity of the calibration curve (r > 0.995) was obtained in the concentration range of 0.5–20 ng/mL, except for stanozolol. The detection limits (S/N = 3) of anabolic steroids were in the range 9–182 pg/mL and the proposed method showed 20–33-fold higher sensitivity than the direct injection method. The within-day and between-day precisions were below 4.0% and 7.3% (n = 5), respectively. This method was applied successfully to the analysis of urine samples without the interference peaks. The recovery rates of anabolic steroids spiked into urine samples were above 85%. This method is useful to analyze the urinary levels of these compounds in anti-doping tests.     

Analysis of methyloxime derivatives of intact esters of testosterone and boldenone in equine plasma using ultra high performance liquid chromatography tandem mass spectrometry

Analysis of equine plasma samples to detect the abuse of anabolic steroids can be complicated when the parent steroid is endogenous to the animal. Anabolic steroids are usually administered intramuscularly as synthetic esters and therefore detection of the exogenous esters provides unequivocal proof of illegal administration. An ultra high performance liquid chromatography tandem mass spectrometric (UPLC‐MSMS) method for the analysis of esters of testosterone (propionate, phenylpropionate, isocaproate, and decanoate) and boldenone (undecylenate) in equine plasma has been developed. Esters were extracted from equine plasma using a mixture of hexane and ethyl acetate and treated with methoxyamine hydrochloride to form methyloxime derivatives. Metenolone enanthate was used as an internal standard. After chromatographic separation, the derivatized steroid esters were quantified using selected reaction monitoring (SRM). The limit of detection for all of the steroid esters, based on a signal to noise ratio (S/N) of 3:1, was 1–3 pg/mL. The lower limit of quantification (LLOQ) for the all of the steroid esters was 5 pg/mL when 2 mL of plasma was extracted. Recovery of the steroid esters was 85–97% for all esters except for testosterone decanoate which was recovered at 62%. The intra‐day coefficient of variation (CV) for the analysis of plasma quality control (QC) samples was less than 9.2% at 40 pg/mL and less than 6.0% at 400 pg/mL. The developed assay was used to successfully confirm the presence of intact testosterone esters in equine plasma samples following intramuscular injection of Durateston® (mixed testosterone esters). Copyright © 2011 John Wiley & Sons, Ltd.     

5α-reductase inhibitors: Evaluation of their potential confounding effect on GC-C-IRMS doping analysis

5α-reductase inhibitors (5-ARIs) are considered by the World Anti-doping Agency as potential confounding factors in evaluating the athlete steroid profile, since they may interfere with the urinary excretion of several diagnostic compounds. We herein investigated 5α-reductase inhibitors from a different perspective, by verifying their influence on the carbon isotopic composition of 5α- and 5β-reduced testosterone and nandrolone metabolites. The GC-C-IRMS analysis was performed on a set of urine samples collected from three male Caucasian volunteers after the acute and chronic administration of finasteride in combination with the intake of 19-norandrostenedione, a nandrolone precursor. The excretion and the isotopic profile of androsterone (A), etiocholanolone (Etio) 5α-androstane-3α,17β-diol (5αAdiol), and 5β-androstane-3α,17β-diol (5βAdiol) were determined as well as those of 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE). Pregnanediol (PD) and pregnanetriol (PT) were also measured as endogenous reference compounds to define the individual endogenous isotopic profile. Our results confirmed the impact of finasteride, especially if chronically administered, on the enzymatic pathway of testosterone and nandrolone, and pointed out the influence of 5-ARIs on δ¹³C values of the selected target compounds determined in the IRMS confirmation analysis.     

Nandrolone potentiates arrhythmogenic effects of cardiac ischemia in the rat.

Anabolic steroid abuse has been associated with thrombosis and arteriosclerosis, both of which predispose to myocardial ischemia and infarction. However, there are reports of sudden cardiac death in the absence of thrombus and atheroma following anabolic steroid use. Although treatment with the commonly abused steroid, nandrolone, has been shown to decrease recovery of systolic function following ischemia in isolated rat hearts, it is unknown whether anabolic steroids can increase the incidence of fatal arrhythmia associated with cardiac ischemia. Anesthetized male Sprague-Dawley rats were administered vehicle or nandrolone (10-160 microg/kg/min iv) 10 min prior to 15-min occlusion of the left anterior descending coronary artery followed by 10-min reperfusion. Nandrolone, in this dose range, did not significantly change heart rate, blood pressure, or cardiac rhythm in the absence of ischemia. However, the fraction of rats surviving ischemia was significantly (p < 0.05) decreased by nandrolone at both 40 and 160 microg/kg/min, while survival time during ischemia was decreased significantly (p < 0.001) by nandrolone 160 microg/kg/min. An increase (p < 0.05) in the duration of ventricular fibrillation was noted at the highest compared to the lowest dose of nandrolone, corresponding to a significant increase in the fraction of rats experiencing ventricular fibrillation (p < 0.01). Nandrolone had no effect on the frequency or duration of ventricular fibrillation or survival time during reperfusion. Although the mechanisms underlying these effects are currently unclear, they indicate that exposure to anabolic steroids in combination with transient reductions in coronary blood flow may explain some reports of sudden cardiac death in anabolic steroid users.