Studies of Metabolism of Round Spermatids: Cytochalasin B Binding to Cell Membrane in Relation to Glucose Transport

Cytochalasin B inhibited uptake of 2-deoxy-D-glucose in rat spermatids (Ki = 6.3 X 10(-7) M). This inhibition was reversible. The [3H]cytochalasin B was found to bind to spermatid plasma membranes at low drug concentrations. Lineweaver-Burk plots of binding data indicated that there was a class of high affinity sites (Kd = 2.9 X 10(-7) M). The results suggest that the high affinity cytochalasin B binding sites of spermatids are membrane-associated substances and are intimately related to the glucose transport system.     

Prostatic Origin of Pyruvate Kinase Activity in Human Seminal Plasma

Pyruvat-Kinase-Aktivität aus der Prostata im Spermaplasma des Menschen
Die Pyruvat-Kinase-Aktivität findet man im Sperma-Plasma bei Menschen mit Normozoospermie, Oligozoospermie, Azoospermie und Vasektomie. Um die Herkunft dieses Enzyms herauszufinden, wurde die fraktionierte Ejakulat-Methode angewandt. Spermato zoenzahl, Aktivität der sauren Phosphatase und Fruktosekonzentration waren die Kontrollparameter, um genaue Ergebnisse zu sichern. Der Beweis wird erbracht, daß die Prostata die Hauptquelle der Pyruvat-Kinase im Spermaplasma des Menschen darstellt.     

Changes Induced to Bull Spermatids and Testicular Spermatozoa by a Single Peritesticular Injection of Ethylene Dibromide

Peritesticular injection of ethylene dibromide to bulls resulted in misshaping, abnormal chromatin condensation and decrease of UV-DNA and UV-protein contents of elongating spermatids.     

人睾丸圆形精子细胞在体外向长形精子细胞分化

目的:探讨人睾丸生精细胞在体外培养条件下发生的分化。方法:取梗阻性无精子症患者睾丸活检标本,机械法离散睾丸细胞。①睾丸细胞混合培养,每24 h观察,计数分析长形精子细胞比率的变化;②显微操作挑取圆形精子细胞,观察单个细胞在微滴培养过程中变形分化的情况。结果:在添加卵泡刺激素、睾酮的HTF培养液中进行睾丸细胞混合培养,24 h后长形精子细胞比率较培养前显著增加(P<0.05);单个圆形精子细胞培养,可见到圆形精子细胞长出鞭毛转化为长形精子细胞,48 h的转化率为3.54%。Vero细胞条件培养液中人睾丸生精细胞的分化与HTF培养液中相同,两者无显著差异。结论:人睾丸组织的圆形精子细胞在体外可分化为长形精子细胞,Vero细胞条件培养液对此分化无促进作用。     

Presence of Specific Receptor Binding Sites for Inhibin in Rat Spermatids

Vorhandensein von spezifischen Rezeptorbindungs-Plätzen für Inhibin in Ratten-Spermatiden
In Rattenspermatiden konnten hohe Werte für Inhibin der Anwesenheit einer hohen Affinitäts-Klasse von Inhibin-Rezeptoren zugeschrieben werden. Die in vitro-Inkorporation von ³H-Leucin an immunopraezipitables Inhibin weist darauf hin, daß die Biosynthese von Inhibin in den Spermatocyten erfolgt. Für eine Synthese von Inhibin durch die Spermatiden ergab sich keinerlei Beweis.     

Pyruvate kinase in human brain tumours. Its significance in the treatment of gliomas

Summary Pyruvate kinase isozyme distribution was studied in 101 intracranial tumours of various nature and origin, and in normal human brain (both foetal and adult). In foetal brain, five different forms could be detected by electrophoresis (K₄, K₃M, K₂M₂, KM₃, and M₄). In adult brain, the M₄ type, K₃M hybrid, and K₄ are present; the M type is largely predominant. Alanine inhibition of pyruvate kinase can be used to discriminate between M and K-type pyruvate kinase. The results obtained in an alanine inhibition test are in agreement with the electrophoretic pattern. Pyruvate kinase from foetal brain and brain of a newborn is more inhibited compared with pyruvate kinase from adult brain. In adult brain a high residual activity of pyruvate kinase is found in the presence of alanine. Well differentiated neuroepithelial tumours,i.e., astrocytomas, oligodendrogliomas, and ependymomas showed also relatively high residual activities, though less than in normal adult brain. On the contrary, in poorly differentiated gliomas low residual activity was found. Alanine inhibition of pyruvate kinase correlates well with degree of differentiation of these tumours. There is also a strong correlationship between alanine inhibition of pyruvate kinase and one year survival after total or subtotal resection of gliomas in adults.When in gliomas the residual activity is determined not in the centre of the tumour but more towards the periphery, much higher residual activity is found. It is suggested that brain biopsies in which a residual activity higher than 70% is found probably contain no tumour in the paraffin slides.Poorly differentiated gliomas were characterized by the presence of type K, and the hybrids K₃M. In well differentiated gliomas, besides K₄ and K₃M, M₄ was also present. Alanine inhibition was in agreement with the electrophoretic pattern in all tumours. In children (age 1–11 years) gliomas showed no correlation between the distribution of pyruvate kinase isozymes and the histological classification and grading. Of the non-neuro-epithelial tumours studied relatively high residual activities were found for pyruvate kinase in haemangioblastomas, chromophobe adenomas, and craniopharyngiomas. This was also found in an arteriovenous malformation. Other non-neuroepithelial tumours showed much less residual activity. These included benign tumours, meningiomas, neurilemmomas, malignant metastatic tumours, and fibrosarcomas. It was also found in cavernomas. The determination of pyruvate kinase activity in the presence of alanine may be useful for the diagnosis and treatment of intracerebral tumours, in particular gliomas of adults.The alanine inhibition test is a reliable quantitative procedure. It can be performed in 10 minutes, and may well fit in the scope of a surgical procedure.     

离子交换法从发酵液中提取丙酮酸

选择122树脂用于丙酮酸发酵液的脱色,在发酵液丙酮酸质量浓度为60g/L、pH3.0、脱色空间流速为1.8mL/(mL*h)的条件下可取得较好的脱色效果,丙酮酸损失率低于6%.从8种碱性阴离子交换树脂中筛选出330弱碱性阴离子树脂(氯型),用于从发酵液中提取丙酮酸.考察了不同操作条件对固定床离子交换效果的影响,上柱料液pH的变化对流出曲线的形状影响不大.当上柱料液的pH和丙酮酸质量浓度分别控制在4.0和40g/L时,可以获得较高的有效体积交换容量(分别为0.534mol/L树脂和0.530mol/L树脂).实验范围内体积流量对交换过程的影响不大,在较低的离子交换空间(0.44mL/(mL*h))下有效体积交换容量较高(0.604mol/L树脂).考察了固定床洗脱工艺条件对洗脱效果的影响.当洗脱剂盐酸的浓度为2mol/L、洗脱空间流速控制在0.44mL/(mL*h)左右时洗脱效果较好.采用较佳的工艺条件进行固定床单柱操作,实验得到离子交换单元的丙酮酸收率为97.0%.     

Preventive Effect of Ethyl Pyruvate on Postoperative Adhesion Formation Following Abdominal Surgery

Objective: Postoperative adhesions are among the major causes of morbidity and mortality following abdominal surgery. As an antioxidant and antiinflamatory agent, the potential effect of ethyl pyruvate on adhesion prevention has not been clearly studied. We aimed to investigate the possible anti-adhesive effect of ethyl pyruvate compared with an effective barrier membrane, Seprafilm, in a rat cecal abrasion model. Materials and Methods: Male Wistar albino rats separated into three adhesion model groups (n = 8, each) with applications of different agents during surgery: control (intraperitoneal normal saline), Seprafilm group (intraperitoneal Seprafilm), and Ethyl pyruvate group (40 mg/kg intraperitoneal ethyl pyruvate). Postoperative adhesion was graded both macroscopically and histopathologically. Malondialdehyde and nitric oxide levels were determined from tissue samples for assessment of oxidative stress. Results: Seprafilm and Ethyl pyruvate groups had lower adhesion scores (both macroscopic and microscopic) and decreased malondialdehyde and nitric oxide levels compared to the control group (p < 0.05 for all parameters). The results were comparable for both Seprafilm and Ethyl pyruvate groups for all parameters (p > 0.05). Conclusions: Intraperitoneal ethyl pyruvate application reduced the incidence and the extent of postoperative adhesions in rat cecal abrasion model. Ethyl pyruvate also had comparable overall efficacy for adhesion prevention as Seprafilm.     

Metabolism of Round Spermatids in the Rat: Effect of Gossypol on the Glucose Transport/Stoffwechsel der runden Spermatiden bei der Ratte: Der Einfluß von Gossypol auf den Glukose-Transport

Low dose of gossypol (5 microM) completely inhibited uptake of 2-deoxy-D-glucose by rat spermatids. With gossypol 2-deoxy-D-glucose transport into spermatids increased curvelinearly for 10 minutes after the start of incubation, but reached a plateau afterwards, whereas without gossypol it continuously increased. The levels of fructose-1,6-bis-phosphate (FBP) and ATP were inversely correlated when the cells were exposed to glucose. However, in the presence of gossypol the levels of ATP and FBP decreased simultaneously. In addition, gossypol at 10 microM stimulated oxygen consumption when lactate was present. These results suggest that gossypol probably inhibits glucose transport into spermatids by lowering the ATP level by uncoupling respiratory chain-linked phosphorylation.     

脊髓背角星形胶质细胞中丙酮酸脱氢酶激酶4在吗啡耐受小鼠中的作用

目的 探讨脊髓背角星形胶质细胞中丙酮酸脱氢酶激酶4(PDK4)在吗啡耐受小鼠中的作用。方法 SPF级雄性C57b1/6小鼠24只,6～8周龄,体重22～25 g。采用随机数字表法分为四组：生理盐水组(C组)、吗啡组(M组)、PDK4抑制剂二氯乙酸(DCA)组(D组)和吗啡+DCA组四组(MD组),每组6只。C组鞘内注射生理盐水10μl,每日2次,连续5 d; M组、D组和MD组分别鞘内注射含吗啡10μg、DCA 200μg和吗啡10μg+DCA 200μg的生理盐水10μl,每日2次,连续5 d。首次给药前和每日第1次给药后1 h检测小鼠甩尾潜伏期(TFL)。最后一次给药后处死小鼠,采用Western blot法检测脊髓背角中PDK4、磷酸化丙酮酸脱氢酶(p-PDH)、p-S²⁹³-PDH、p-S³⁰⁰-PDH蛋白含量,免疫荧光组织化学法检测脊髓背角中PDK4与星形胶质细胞标志物胶质纤维酸性蛋白(GFAP)共表达情况。结果 与首次给药前比较,第1—5天第1次给药后1 h M组和MD组TFL明显延长(P<0.05)。与C组比较,M组第1—...     

Stimulation of Protein Synthesis in Pachytene Primary Spermatocytes from the Human Testis by Pyruvate

A sequential enzymatic incubation in collagenase and trypsin was carried out to yield a suspension of viable single cells from the seminiferous epithelium of adult human testis. The cell suspension predominantly consisted of pachytene primary spermatocytes (15%), round spermatids (32%), and condensing spermatids and residual bodies (21%). Human pachytene spermatocytes were isolated by unit gravity sedimentation using the methods originally developed for murine tissue. The spermatocyte-enriched fraction was 79% pure. When the effect of energy sources on protein synthesis by spermatocytes was examined, the highest rate of protein synthesis with pyruvate was found among four kinds of substrates added at a concentration of 10 mM. As shown with murine spermatocytes, the rate of protein synthesis by the human spermatocytes is probably regulated by pyruvate.     

Morphological effects of the catecholestrogens on cells of the seminiferous tubules of Sprague-Dawley rats

Estradiol-17 beta (E2) and the two catecholestrogens 2-OHE2 and 4-OHE2, when daily administered at low doses of 10-40 ng/rat, were cytotoxic to the seminiferous epithelium. The structural changes seen after seven days exposure included abnormal meiotic type II cells with uneven chromosome distribution, the formation of binucleated and multinucleated giant cells, of which many were sloughed into the lumina of the seminiferous tubules. The effect of the 4-OHE2 metabolites were always more pronounced that that of 2-OHE2 or E2. After 21 daily exposures, 4-OHE2 proved to be very toxic, the seminiferous tubules were markedly denuded and numerous giant cells were present in the lumina. The catecholestrogens also caused a significant lowering (P less than 0.02) of testosterone serum levels after eight days exposure. E2 at 40 ng/rat/day had no effect on testosterone production. At these low doses the catecholestrogens did not affect gonadotropin release after eight days exposure. Our results indicate that the morphological lesions could not exclusively be attributed to testosterone withdrawal and that a direct effect on developing spermatids is also indicated.