猕猴前列腺增生动物模型的建立

利用猕猴（Macaca mulatta）建立前列腺增生动物模型,并探讨丙酸睾酮（TP）诱导猕猴前列腺增生模型的最佳剂量及给药时间。雄性猕猴12只,随机分为3个剂量的实验组和对照组共4组,每组3只。去势8周后,皮下注射给药。实验组按低、中、高剂量分别给予丙酸睾酮（TP）0.8、2.5、7.5 mg/(kg?d),对照组给予等体积溶剂,连续8周。B型超声探测去势前、去势后8周及TP干预4周、8周时猕猴前列腺体积,并采集分离各个实验阶段的血清备用。给药8周后处死动物,取前列腺,称量湿重,测量体积,计算前列腺重量指数及体积指数,H.E染色切片观察前列腺增生情况,并进一步测量腺腔面积及腺上皮细胞高度。同时,采用ELISA方法测定血清及前列腺组织中二氢睾酮（DHT）水平。B型超声结果显示,去势8周时,各组猕猴前列腺体积均明显小于去势前（P < 0.05）。TP干预4周及8周时,各剂量组猕猴前列腺体积均显著大于对照组（P < 0.05）,且在干预4周TP中剂量组达到最佳效果（P < 0.01）。而TP干预4周与8周相比,各组间并无显著性差异（P > 0.05）。解剖结果显示,各实验组猕猴前列腺湿重、体积及脏器指数均明显大于对照组（P < 0.05）,且在中剂量组达到最大值。而显微图像分析结果显示,实验组猕猴前列腺上皮细胞增生,与对照组比较,各剂量组猕猴前列腺腺腔面积明显增加（P < 0.01）,腺上皮细胞高度明显增高（P < 0.01）。二氢睾酮（DHT）水平检测结果显示,与对照组相比,药物干预后各实验组猕猴血清中DHT含量明显增高（P < 0.01）,且在中剂量组达到最大值。TP干预4周与8周相比,各组间并无显著性差异（P > 0.05）。同时,各实验组前列腺组织中DHT含量相较于对照组也明显增高,但剂量-效应关系不显著,中剂量组优于高、低剂量组。TP药物干预去势猕猴可成功建立猕猴前列腺增生模型,初步判定较为适宜的造模条件为丙酸睾酮给药剂量2.5 mg/(kg?d),给药时间4周。     

中国大鲵肌肉蛋白肽对BPA诱导小鼠精子发生障碍的治疗作用及其机制研究

摘要 目的：研究中国大鲵肌肉蛋白肽（The protein and peptide extracts from muscles of Chinese giant salamanders,SP）对双酚A（bisphenol A,BPA）诱导的小鼠生精障碍的保护作用,并初步探讨其作用机制。方法：40只C57BL/6 雄性小鼠分为四组,分别为Control组、BPA组、BPA+CS（Compound Substance）组、BPA+SP组。BPA组使用50 mg/kg/d的BPA腹腔注射,BPA溶解于玉米油;Control组只腹腔注射玉米油。BPA+CS组灌胃其他有利于生精壮阳的复合物用作对照,复合物溶解于生理盐水中;BPA+SP组灌胃上述复合物联合大鲵肌肉蛋白肽,以上灌胃剂量均4 g/kg/d。连续造模28天,期间每周测定小鼠体重,造模结束后测定睾丸体积、睾体比,取附睾精子使用CASA计算机辅助分析系统测定精子数目、精子活力,ELISA法测定血清睾酮含量,HE染色、TUNEL染色分析睾丸组织病理学,最后采用免疫荧光染色及Western blotting分析转移相关基因2（MTA2）的表达情况、油红O染色观察支持细胞体内、体外吞噬作用。结果：与对照组比较,BPA组睾丸体积（P<0.05）、睾丸重量（P<0.05）、睾体比（P<0.05）、精子数目（P<0.05）、精子活力（P<0.05）、睾酮含量（P<0.01）均显著降低,睾丸组织形态受损（P<0.05）、生精细胞凋亡增多（P<0.01）、MTA2表达量降低（P<0.01）、支持细胞吞噬功能减弱（P<0.01）;BPA+CS组较BPA组无明显变化,BPA+SP组以上变化显著改善（P<0.05）。结论：大鲵肌肉蛋白肽对BPA诱导的小鼠生精功能障碍有明显的保护作用,作用机制可能与干预MTA2表达进而增强支持细胞的吞噬作用相关。     

夹竹桃麻素对双酚a诱导的成年雄性小鼠精子损伤作用的实验研究

目的:研究NADPH氧化酶抑制剂夹竹桃麻素(Apocynin)对双酚a(Bisphenol a,BPA)诱导的成年雄性小鼠精子损伤过程中的作用。方法:成年雄性小鼠给以BPA刺激,给以Apocynin(1 mg/kg/day和10 mg/kg/day,分别处理7 day)进行治疗,观察其对BPA诱导的成年雄性小鼠精子损伤的作用。结果:BPA处理组小鼠附睾精子数目和活力明显降低,血清中睾酮和黄体生成素水平明显减少;Apocynin治疗明显增加BPA处理组小鼠附睾中精子数目和活力,但是对血清中睾酮和黄体生成素水平没有明显影响。另外,BPA处理组小鼠睾丸中丙二醛(Malonaldehyde,MDA)水平明显增加;Apocynin治疗明显抑制了BPA处理组小鼠睾丸中MDA水平。结论:NADPH氧化酶抑制剂Apocynin减轻BPA诱导的成年雄性小鼠精子损伤。     

长期酒精摄入对雄性大鼠生殖系统的损伤

摘要目的：研究长期酒精摄入对雄性大鼠生殖系统的损伤机制。方法：选用8 周龄的SD 大鼠,进行随机分组：对照组（5％蔗糖, 口服）;酒精组（4g/kg,口服）。连续12周后,分别取附睾考察精子数目、活力;取血清检测睾酮和促黄体生产素（LH）含量;计算睾 丸- 体重比,并检测睾丸中丙二醛（MDA）、谷胱甘肽（GSH）含量以及谷胱甘肽过氧化物酶（GPx）和超氧化物歧化酶（SOD）的活 性;同时检测凋亡相关蛋白bax,bcl-2 以及caspase-3 前体和剪切体的蛋白表达。结果：酒精组12 周后,大鼠的睾丸- 体重比明显 降低（P<0.05）,精子数目减少（P<0.01）,精子活力下降（P<0.01）;血清中睾酮含量下降（P<0.05）,LH 含量增加（P<0.05）;睾丸中 MDA 含量增加（P<0.01）,GSH 含量降低（P<0.05）,GPx 和SOD活性下降（P<0.01）;凋亡相关蛋白bax 表达增加（P<0.05）,caspase -3 剪切体与前体的比值增加（P<0.01）。结论：长期摄入酒精引起的大鼠睾丸内氧化应激水平的增加是其导致其生殖系统损伤的重 要因素之一。     

长期酒精摄入对雄性大鼠生殖系统的损伤

目的：研究长期酒精摄入对雄性大鼠生殖系统的损伤机制。方法：选用8周龄的SD大鼠,进行随机分组：对照组（5％蔗糖,口服）;酒精组（4g／kg,口服）。连续12周后,分别取附睾考察精子数目、活力;取血清检测睾酮和促黄体生产素（LH）含量;计算睾丸一体重比,并检测睾丸中丙二醛（MDA）、谷胱甘肽（GSH）含量以及谷胱甘肽过氧化物酶（GPx）和超氧化物歧化酶（SOD）的活性;同时检测凋亡相关蛋白bax,bcl-2以及caspase．3前体和剪切体的蛋白表达。结果：酒精组12周后,大鼠的睾丸．体重比明显降低（P〈0．05）,精子数目减少（P〈0．01）,精子活力下降（P〈0．01）;血清中睾酮含量下降（P〈0．05）,LH含量增加（P〈0．05）;睾丸中MDA含量增加（P〈0．01）,GSH含量降低（P〈0．05）,GPX和SOD活性下降（P〈0,01）;凋亡相关蛋白bax表达增加（P〈0．05）,caspase-3剪切体与前体的比值增加（P〈O．01）。结论：长期摄入酒精引起的大鼠睾丸内氧化应激水平的增加是其导致其生殖系统损伤的重要因素之一。     

姜黄素对急性游泳训练小鼠骨骼肌损伤的保护作用

目的：探讨姜黄素对急性游泳训练小鼠骨骼肌损伤的保护作用。方法：成年雄性BALB/C小鼠随机分为安静对照组、运动对照组、运动+姜黄素组［100 mg/（kg·d）］和安静+姜黄素组［100 mg/（kg·d）］。干预期为4w,干预期最后1w同时进行游泳运动训练,每天训练90min,采用以上运动方式连续运动7d,末次运动完成后即刻处死小鼠。测定血清肌酸激酶（CK）含量及骨骼肌超氧化物歧化酶（SOD）、谷胱甘肽（GSH）、活性氧（ROS）和丙二醛（MDA）水平,并观察骨骼肌普通及超微病理学改变。结果：与运动对照组相比,姜黄素干预明显抑制了游泳运动导致的小鼠血清CK水平的上升（P<0.01）,减轻了运动导致的骨骼肌普通及超微病理结构异常。姜黄素干预显著抑制了运动导致的小鼠骨骼肌GSH水平的下降（P<0.05）,同时拮抗了ROS和MDA含量水平的上升（P<0.01）。结论：姜黄素对小鼠急性游泳训练导致的骨骼肌损伤具有明显的抗氧化保护作用。     

贯叶连翘提取物对小鼠抗应激反应及运动力竭小鼠抗氧化活性的影响

目的：研究贯叶连翘提取物（HPLE）对小鼠抗应激反应及运动力竭小鼠抗氧化活性的影响。方法：ICR小鼠,雌雄各半,随机均分为生理盐水（NS）对照组及高、中、低剂量HPLE组。分别采用负重游泳、常压耐缺氧和耐低温实验,观察小鼠抗急性应激反应能力,HPLE组分别按1.5 g/kg、0.75 g/kg和0.38 g/kg,ig,Bid,连续给药7 d;NS组等体积生理盐水ig。另取ICR小鼠40只,雌雄各半。随机均分为NS对照组及HPLE高、中、低剂量组。分别按ig HPLE 1.5 g/kg、0.75 g/kg和0.38 g/kg,q.d;对照组：ig等量NS,qd。连续用药2周后,开始每天进行游泳训练0.5 h,到第21天后,游泳力竭后休息20 min,断头取血,制备血清,检测小鼠血清中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）活性和丙二醛（MDA）的含量变化。结果：HPLE可延长小鼠负重游泳时间,缺氧存活时间及提高耐低温能力,并能升高运动力竭小鼠血清中SOD和GSH-Px活性,降低MDA的含量。结论：HPLE可提高小鼠应激反应能力,并具有抗氧化活性。     

n-6/n-3 多不饱和脂肪酸营养失衡对小鼠精子发生的影响

目的:探讨n-6/n-3多不饱和脂肪酸营养失衡对小鼠精子发生的影响。方法:健康的30只C57/B6雄鼠随机分为对照组(CON)、高脂组(HF)、花生四烯酸组(HF+AA)。喂食16周,做合笼实验并记录致孕率,通过精子动力分析仪检测小鼠精子活力和数量的变化,用Elisa试剂盒测血清中睾酮和甘油三酯水平。通过病理组织染色观察小鼠睾丸组织的形态学变化。利用Realtime-PCR的方法检测小鼠睾丸中Dazl基因表达水平的变化。结果:高脂组、花生四烯酸组与对照组相比精子活力[(16±0.01;12.33±2.83 vs72.2±12.73)%,P0.001],精子数量[(7.5±1.13;6±0.14 vs 13.87±0.35)million/m L,P0.001],致孕率[(28.57;14.29 vs 78.57)%,P0.001]及血清睾酮含量[(0.35±0.14;0.27±0.07 vs 3.51±0.7)ng/m L,P0.001]均显著性降低。高脂组、花生四烯酸组与对照组相比,血清中甘油三酯的含量显著增高[(0.74±0.04;0.74±0.04 vs 0.45±0.04)mmol/L,P0.001]。病理组织染色观察到花生四烯酸组小鼠睾丸组织出现了明显异形,曲细精管内部的初级精母细胞明显缺失,管腔中从初级精母细胞到精子的发生过程出现了变异,精子的数量也显著性下降。参与精子生成过程中的减数分裂前的有丝分裂增殖期、精原细胞的发育等过程的Dazl基因在高脂组和花生四烯酸组小鼠睾丸中的表达量与对照组相比显著降低(0.87±0.05;0.65±0.03 vs 1.07±0.04,P0.05)。结论:膳食中n-3/n-6多不饱和脂肪酸失衡会导致雄鼠精子发生发育的障碍     

积雪草对早期糖尿病肾病大鼠TGF-β1表达及相关下游信号的影响

目的：通过研究积雪草（CA）对早期糖尿病肾病大鼠转化生长因子β₁（TGF-β₁）表达及相关下游信号的影响,阐明积雪草防治早期糖尿病肾病（DN）的分子机制。方法：60只雄性SD大鼠,按体重随机分为假手术组（n=10）和造模组（n=50）。造模组大鼠进行右肾切除术,1周后给以腹腔注射链脲佐菌素（STZ）30 mg/kg,连续给3 d;72 h后测血糖,以 ≥ 16.7 mmol/L,尿糖+++以上及尿量大于对照组的50%为DN模型成模标准。假手术组进行右肾被膜损伤,并注射相应量生理盐水。造模组通过灌胃给药,分为：DN模型组（模型组）、DN+福辛普利组（蒙组1.6 mg/kg·d）、DN+积雪草高剂量组（高剂量组16.8 mg/kg·d）、DN+积雪草中剂量组（中剂量组11.2 mg/kg·d）和DN+积雪草低剂量组（低剂量组5.6 mg/kg·d）（n=10）,连续给药16周,每日上午1次灌胃。利用实时荧光定量PCR和Western blot分别检测肾组织中TGF-β₁、TβR1、TβR2、Smad2/3、p-Smad2/3及Smad7 mRNA和蛋白的表达。结果：与假手术组相比,DN组TGF-β₁、TβR1、TβR2、Smad2/3 mRNA和蛋白表达及Smad2/3蛋白的磷酸化水平显著增加（P<0.05）、Smad7 mRNA和蛋白表达明显减少（P<0.05）,而福辛普利和高剂量积雪草能倒转DN引起的TGF-β₁、TβR1、TβR2、Smad2/3 mRNA和蛋白表达增加（P<0.05）及Smad7 mRNA和蛋白表达降低（P<0.05）。结论：积雪草可能通过调控TGF-β₁/Smad信号通路起到防治DN的作用。     

二氢杨梅素对2型糖尿病小鼠认知功能障碍的影响

目的：观察二氢杨梅素（DHM）对2型糖尿病（T2DM）小鼠认知功能障碍及海马中BDNF蛋白表达的影响。方法：将40只C57BL/6J小鼠首先随机分为两组：正常对照组（n=8）：普通饲料喂养;2型糖尿病模型组（n=32）：高糖高脂联合100 mg/kg的STZ处理（造模过程中死亡5只,不成功3只）。24只建模成功的小鼠随机分成3组：T2DM组、T2DM+L-DHM组和T2DM+H-DHM组,3组小鼠高糖高脂喂养,同时分别用等体积生理盐水、125 mg/（kg·d）的DHM和250 mg/（kg·d）的DHM （1次/天,灌胃）处理16周。正常对照小鼠继续普通饲料喂养,同时用等体积生理盐水（1次/天,灌胃）处理16周。16周后测定小鼠体重、空腹血糖、进行腹腔注射葡萄糖耐量实验和相关行为学实验。最后,Western blot检测各组小鼠海马中BDNF蛋白的表达。结果：高糖高脂联合100 mg/kg的STZ成功建立2型糖尿病小鼠模型。16周后,与正常对照组相比,T2DM组小鼠体重明显下降,空腹血糖显著升高,糖耐量显著异常;而T2DM+DHM组相比T2DM组小鼠体重却显著增加、空腹血糖降低,且H-DHM可显著改善T2DM小鼠糖耐量异常。行为学实验结果显示：与正常对照组相比,T2DM组小鼠学习记忆能力明显下降;与T2DM组相比,T2DM+DHM组小鼠学习记忆能力得到改善,且H-DHM组更为明显。Western blot结果显示：与对照组相比,T2DM组小鼠海马中BDNF蛋白表达显著下降,而DHM组相比T2DM组小鼠其BDNF蛋白的表达明显增加。结论：二氢杨梅素可改善2型糖尿病小鼠认知功能障碍,其机制可能通过降血糖作用,并激活海马中BDNF蛋白表达。     

形态学与形态计量学观察大豆异黄酮对前列腺增生大鼠的作用

目的探讨不同剂量大豆异黄酮(SI)对前列腺增生大鼠组织形态学和超微结构的影响。方法应用丙酸睾酮诱导雄性SD大鼠前列腺增生,随机分为五组:正常对照组、模型组和3个大豆异黄酮剂量组,分别灌胃SI 60、120、240 mg/(kg.d),28 d后,光镜观察前列腺组织形态,同时结合图像分析系统检测前列腺腺体、间质的形态计量学改变,透射电镜观察前列腺细胞超微结构的变化。结果各剂量大豆异黄酮均可降低前列腺增生大鼠前列腺湿重、指数及体积,降低上皮细胞高度、腺体面积、腺体相对总体积、单位体积内腺体平均直径、平均体积、平均表面积和间质相对总体积,提高腺体数目、腺体数密度、腺体表面积/腺体体积和腺体平均曲率。结论大豆异黄酮具有抑制大鼠前列腺增生的作用。     

阿里红黄酮对衰老模型小鼠的抗衰老作用

目的：研究阿里红黄酮对衰老模型小鼠的抗衰老作用。方法：将小鼠随机分为6组（n=12）：正常对照组,衰老模型组,阳性对照组,低、中、高剂量阿里红黄酮组。除正常对照组外,其余各组均采用D-半乳糖颈背部皮下注射建立亚急性衰老小鼠模型,用不同剂量的阿里红黄酮（100、200和400 mg/（kg·d））灌服小鼠6周后,计算衰老模型小鼠脑指数及脾脏指数、胸腺指数,测定其脑组织丙二醛（MDA）含量及谷胱甘肽过氧化物酶（GSH-Px）活性、肝组织过氧化氢酶（CAT）及超氧化物歧化酶（SOD）活性。结果：阿里红黄酮3个剂量组可不同程度的升高衰老模型小鼠的脑指数、脾脏指数、胸腺指数、脑组织中的GSH-Px活性及肝组织中的CAT、SOD活性,降低其脑组织中的MDA含量。结论：阿里红黄酮可能通过提高机体的抗氧化能力而达到抗衰老作用。     

Effect of retrotestosterone on accessory sex organs & spermatogenesis of rat

Retrotestosterone (17beta-hydroxy 9beta 10alpha androst 4-en 3 one) (RT), testosterone propionate (TP), and a combination of TP and RT were administered to adult male rats in order to study the effects of such treatment on male sex organs and spermatogenesis. Although TP treatment did not produce significant reduction in testis weight, RT and RT+TP did. Seminal vesicle (SV) weight was increased by TP treatment and TP+RT treatment, but it was decreased with the RT treatment. Ventral prostate (VP) weight was increased significantly by TP and TP+RT treatment, whereas RT did not alter VP weight. The The pituitary weight of RT- and RT+TP-treated rats was significantly reduced but that of the TP rats was unaltered. Resting spermatocytes, pachytene spermatocytes, Stage 7 spermatids, and spermatogonia were increased in all treatment groups. In castrated rats, the increase in VP and SV weight was significant in the group treated with TP, but in the RT-treated group, S V and VP weights were significantly reduced. Simultaneous administration of TP and RT in 1:1, 1:4, and 1:8 ratios failed to produce statistically significant increases in SV and VP weight. The group treated with 1:20 ratio of RT:TP produced highly significant incre ases in SV and VP weights. In the spermatodynamic study, results showed that RT is comparatively more potent than TP in stimulating spermatogenesis. RT+TP treatment produced maximum increase in the count of resting and pachytene spermatocytes, whereas spermatogonia and Stage 7 spermatids were more than in the TP-treated group but less than in the RT-treated group. The findings indicate that RT is weakly androgenic and unable to stimulate accessory organs but that it is able to block the effect of endogenous androgen on the target tissue.     

Use of Tregs as a cell‐based therapy via CD39 for benign prostate hyperplasia with inflammation

Benign prostatic hyperplasia (BPH) occurs most commonly among older men, often accompanied by chronic tissue inflammation. Although its aetiology remains unclear, autoimmune dysregulation may contribute to BPH. Regulatory T cells (Tregs) prevent autoimmune responses and maintain immune homeostasis. In this study, we aimed to investigate Tregs frequency, phenotype, and function in BPH patients and to evaluate adoptive transfer Tregs for immunotherapy in mice with BPH via CD39. Prostate specimens and peripheral blood from BPH patients were used to investigate Treg subsets, phenotype and Treg‐associated cytokine production. Sorted CD39^+/? Tregs from healthy mice were adoptively transferred into mice before or after testosterone propionate administration. The Tregs percentage in peripheral blood from BPH patients was attenuated, exhibiting low Foxp3 and CD39 expression with low levels of serum IL‐10, IL‐35 and TGF‐β. Immunohistochemistry revealed Foxp3+ cells were significantly diminished in BPH prostate with severe inflammatory. Although the Tregs subset was comprised of more effector/memory Tregs, CD39 was still down‐regulated on effector/memory Tregs in BPH patients. Before or after testosterone propionate administration, no alterations of BPH symptoms were observed due to CD39‐ Tregs in mice, however, CD39⁺Tregs existed more potency than Tregs to regulate prostatic hyperplasia and inhibit inflammation by decreasing IL‐1β and PSA secretion, and increasing IL‐10 and TGF‐β secretion. Furthermore, adoptive transfer with functional Tregs not only improved prostate hyperplasia but also regulated muscle cell proliferation in bladder. Adoptive transfer with Tregs may provide a novel method for the prevention and treatment of BPH clinically.     

心力衰竭大鼠心肌SERCA2a和miR-25-3p/5p表达的改变及泻肺利水方药的干预作用

目的：观察心力衰竭大鼠肌浆网钙ATP酶（SERCA2a） mRNA和miR-25-3p/5p表达水平的变化及中药泻肺利水方药的干预作用。方法：SD大鼠随机分为对照组、模型组、中药组、卡托普利组和地高辛组（n=10）,阿霉素腹腔注射（总剂量15 ml/kg,2周内分6次注射）建立心力衰竭大鼠模型,5周后分别以蒸馏水（10 ml/（kg·d））、泻肺利水中药（22 g/（kg·d））、卡托普利（19 mg/（kg·d））和地高辛（32μg/（kg·d））连续灌胃35 d,观察大鼠心肌SERCA2amRNA、miR-25-3p/5p的表达水平和SERCA2a活性、血浆脑钠肽水平、心输出量和射血分数。结果：模型组大鼠心输出量和射血分数显著降低,心肌SERCA2a mRNA表达水平和活性降低,miR-25-3p和miR-25-5p的表达水平、血浆脑钠肽水平显著升高;泻肺利水中药能提高心肌SERCA2a mRNA表达水平和活性,降低miR-25-3p和miR-25-5p的表达水平,降低血浆脑钠肽水平,提高心输出量和射血分数;卡托普利能提高心肌SERCA2a mRNA表达水平,降低miR-25-3p和miR-25-5p的表达水平,降低血浆脑钠肽水平,提高心输出量;地高辛能提高心肌SERCA2a mRNA表达水平,降低血清脑钠肽水平,提高心输出量。结论：心力衰竭大鼠心肌SERCA2a mRNA的表达下调,miR-25-3p和miR-25-5p的表达上调;泻肺利水方药可以上调SERCA2a mRNA的表达,下调心肌miR-25-3p和miR-25-5p的表达,改善心功能。     

Effects of zinc on the trophic activity of testosterone in androgen target tissues of castrate mice

Swiss, 60-day castrate mice were injected with 0.5, 1.5 or 5.0 mg of testosterone propionate (TP; single dose, subcutaneously) 5 days before sacrifice, in order to investigate the ability of the submandibular gland (SMG) and other androgen target tissues to recover their normal morphology and function. Some animals were additionally injected intraperitoneally with ZnCl2 (0.14 or 0.28 mg Zn2+/animal per day) during the last 15 days before sacrifice. Only SMG tissue fully recovered by TP treatment. ZnCl2 significantly impaired the dose-dependent recovery of the granular ducts of mouse SMG tissue and that of other organs which display 'androgenic' (prostate, epididymis) and 'anabolic' responses (bulbocavernosus muscle). Histological examination of testes and epididymides of intact mice injected with ZnCl2 revealed abnormal spermatogenesis with multinucleated cells and acidophilic bodies within the tubular lumen; the circulating levels of testosterone in these animals were low. In vitro, Zn2+ inhibited androgen-binding activity in SMG cytosol, but the binding capacity increased in SMG of zinc-injected animals. It is suggested that zinc, although essential for the androgenic expression, is critical as far as its intracellular concentrations are concerned and that pharmacological doses of Zn2+ determine androgenic suppression by competition at receptor and acceptor levels.     

Effects of testosterone in the VMN on copulation,partner preference,and vocalizations in male rats

The present study tested whether testosterone propionate (TP) implanted in the ventromedial nucleus (VMN) of the hypothalamus could initiate performance, motivational, or sociosexual components of sexual behavior in castrated male rats. Twenty-seven intact male Long Evans rats were pretested for copulation, partner preference, and 50-kHz vocalization and were subsequently castrated. Approximately 3 weeks after castration, males were retested to confirm that these behaviors had declined, and groups were assigned. Groups 1 and 2 were implanted with bilateral stainless steel cannulae directed at the VMN that were either filled with TP (TVMN group) or remained empty (Blank group). A third group (TSC) was implanted subcutaneously with two 10-mm Silastic capsules filled with testosterone. Restoration of behavior was measured for 2 weeks after implants. We found that copulation and 50-kHz vocalization were not restored by TP in the VMN alone. However, partner preference returned to preoperative levels in both the TVMN and TSC groups, indicating that TP in the VMN was sufficient to restore sexual motivation. Following behavioral testing, prostate glands and seminal vesicles were weighed and confirmed that TP did not leak into the periphery in the TVMN group. Immunostaining for androgen receptors also verified that TP spread was confined to the immediate area surrounding the cannula tip. These results suggest that androgen activation at the VMN is sufficient to induce the motivational components of male sexual behavior, whereas activation of other brain sites is required for copulation and ultrasonic vocalization.     

Effect of testosterone propionate on the induction by 1,2-dimethylhydrazine of angiosarcomas of the renal capsule in castrated mice

Administration of 1,2-dimethylhydrazine (DMH) produced 83% (15/18) of renal capsule angiosarcomas in CBA mice. Castration that preceded the DMH-treatment reduced tumor incidence to 7% (2/29). Simultaneous administration of DMH and testosterone propionate (TP) to castrated males restored the tumor frequency (100%, 24/24). Castrated males that received TP after the cessation of the DMH treatment developed tumors in 10% (3/31). Combined treatment of castrated females with DMH and TP resulted in the development of angiosarcomas in 92% animals (22/24). It is concluded that TP enhances the stage of sarcomogenesis initiation induced by DMH.     

Estradiol and testosterone inhibit rat seminiferous tubule development in a hormone-specific way

Follicle stimulating hormone (FSH), testosterone (T) and estradiol (E₂) are known to regulate testis maturation, and changes in FSH secretion induced by sex steroid treatment may mediate the effects of sex hormones. The aim of this study was to compare the effects of T and E₂ on the pre-meiotic steps of first spermatogenesis and FSH level in rats. Male rat pups were injected daily with 17β-estradiol benzoate (EB; 12.5 μg) or testosterone propionate (TP; 2.5 mg) with the use of one of the two administration modes: 1/transient mode; hormone injections on postnatal days (PND) 1–5 followed by daily vehicle injections until PND 15 (t-EB and t-TP, respectively) or 2/continuous mode; hormone injections on PND 1–15 (c-EB and c-TP, respectively). The control group was injected with vehicle alone. On PND 16, blood was taken for serum hormone measurement and testes were collected for analysis of seminiferous tubule morphometry as well as cell number, proliferation and apoptosis. Testis weight, tubule length, Sertoli and germ cell numbers were reduced, and cell apoptosis in seminiferous epithelium was increased after transient EB and TP treatments. Despite normal or increased FSH secretion, the c-EB treatment inhibited pre-meiotic germ cell development and augmented cell apoptosis, whereas the c-TP treatment reduced the spermatocyte number and inhibited the formation of seminiferous tubule lumen. In conclusion, transient administration of EB or TP during PND 1–5 inhibited testis growth, whereas continuous administration (PND 1–15) impaired pre-meiotic germ cell development in a hormone-specific way.