Massive striatal dopamine release in acute cerebral ischemia in rats

Summary Extracellular dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and cerebral blood flow were simultaneously determined using in vivo brain dialysis and a hydrogen clearance method in the striatum of spontaneously hypertensive rats during ischemia and after recirculation. Massive striatal dopamine release was demonstrated in acutely induced ischemic brain.     

Neuroendocrine control of carbohydrate metabolism in the freshwater bivalve molluscLamellidens marginalis

Summary Blood sugars and foot muscle glycogen were measured in the mussel,L. marginalis after ablation of the cerebral ganglia, and in mussels injected with cerebral ganglionic extract 3 h after ablation. There is a rise in the blood sugar and decrease in foot muscle glycogen 3 h after operation, but no change in sham-operated controls. The effect of ablation is reversed by injecting brain extract into ablated mussels. No such effect could be seen in the controls. The results are suggestive of the presence, in the cerebral ganglia, of a hypoglycaemic factor similar to insulin.     

Postischemic ATP levels predict hepatic function 24 hours following ischemia in the rat

Hepatic function was assessed by the aminopyrine breath test (ABT) in male Sprague Dawley rats 24 h after partial hepatic ischemia. ABT decreased progressively to 26.3 (p less than 0.05) and 19.7% of dose (p less than 0.05) after 90 and 120 min of ischemia, respectively. ABT at 24 h after injury was correlated to the concentration of ATP in the ischemic lobes 1 h after the onset of reperfusion (r2 = 0.971) but not to ALT activity in plasma at 1 h (r2 = 0.391). We conclude that postischemic ATP levels are a better index of subsequent hepatic function than ALT.     

Postischemic ATP levels predict hepatic function 24 hours following ischemia in the rat

Summary Hepatic function was assessed by the aminopyrine breath test (ABT) in male Sprague Dawley rats 24 h after partial hepatic ischemia. ABT decreased progressively to 26.3 (p<0.05) and 19.7% of dose (p<0.05) after 90 and 120 min of ischemia, respectively. ABT at 24 h after injury was correlated to the concentration of ATP in the ischemic lobes 1 h after the onset of reperfusion (r²=0.971) but not to ALT activity in plasma at 1 h (r²=0.391). We conclude that postischemic ATP levels are a better index of subsequent hepatic function than ALT.     

Dial variations in the levels of blood glucose and hepatopancreatic glycogen in the slug,Laevicaulis alte (Ferussac 1821)

Summary InLaevicaulis alte maximal blood glucose level at 00.00 h alternates with minimal level at 12.00 h of the day, while hepatopancreatic glycogen showed an opposite trend. Variations in blood glucose levels are inversely proportional to the corresponding variations in hepatopancreatic glycogen content, while blood glucose level shoots up to a maximum, hepatopancreatic glycogen declines to a minimum and vice versa.Acknowledgment. The authors thank Prof. K.S. Swami for providing facilities. The financial assistance rendered by ICMR (DCR), UGC (VJ) and CSIR (KS), New Delhi, India is gratefully acknowledged.     

Effect of organophosphate pesticide Sumithion (Fenitrothion) on some aspects of carbohydrate metabolism in a freshwater fish, Sarotherodon (Tilapia) mossambicus (Peters)

A lethal (Lc50/48 h - 6 mg/l) concentration of the organophosphate (OP) pesticide Sumithion increased blood glucose levels and phosphorylase activity, but hepatic glycogen registered a fall which indicated that the observed hyperglycemia was due to breakdown of hepatic glycogen.     

Reserpin und Glykogengehalt der Organe

Summary In fasted white mice, 1–18 h after the injection of 5 mg/kg Reserpine the glycogen content of brain, heart, skeletal muscle and liver is significantly increased (about 100%, in liver nearly 300%). It is suggested that this is due to an enhanced synthesis of glycogen from non-carbohydrate material.Concerning the underlying mechanism, it is pointed out that after reserpine there occurs a release of catecholamines from the adrenal medulla and-by stimulation of the anterior pituitary-an enhanced production of corticoids.Simultaneously with the increase of the brain glycogen, the level of lactic acid is decreased, whereas the ATP-, ADP- and AMP-content of the brain remains practically unaffected.

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Ausgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Effect of organophosphate pesticide Sumithion (Fenitrothion) on some aspects of carbohydrate metabolism in a freshwater fish,Sarotherodon (Tilapia)mossambicus (Peters)

Summary A lethal (Lc₅₀/48 h — 6 mg/l) concentration of the organophosphate (OP) pesticide Sumithion increased blood glucose levels and phosphorylase activity, but hepatic glycogen registered a fall which indicated that the observed hyperglycemia was due to breakdown of hepatic glycogen.This work was supported by UGC grant to R.R.     

The effect of chronic heat stress on cortisol levels in the antarctic fishPagothenia borchgrevinki

Radioimmunoassay was used to determine levels of the stress-inducible glucocorticoid, cortisol, circulating in the plasma of the extremely stenothermal Antarctic fishPagothenia borchgrevinki at rest and after heat stress. Fish sampled immediately after capture (–1.9°C) had low cortisol levels (10.4±1.4 ng ml^–1, mean±SEM) as did fish which were laboratory rested for 3 days. Sudden exposure to 5°C (48h) resulted in a peak cortisol value after 3 h (69.9±6.8 ng ml^–1) whereas exposure to 8°C (6h) resulted in a peak value after 1 h (73.5±8.0 ng ml^–1). At both temperatures levels remained significantly elevated (p<0.05) for the entire period of exposure. Increased temperature also resulted in a significant change in haemoglobin, haematocrit and mean cell haemoglobin concentration (MCHC) (p<0.05). Plasma lactate was significantly elevated only after exposure to 8°C (p<0.05). Plasma cortisol levels fromP. borchgrevinki are reported here for the first time and show this cryopelagic Antarctic species to have an unusual hormonal stress profile.     

Circadian rhythmicity in phosphorylase activity and glycogen content in the heart muscle of the scorpion,Heterometrus fulvipes,C.L. Koch

Summary Maximal activity levels of phosphorylase A and AB at 20.00 h alternate with minimal levels at 08.00 h of the day, while the glycogen content exhibited a reverse trend in the heart of the scorpion,Heterometrus fulvipes.Acknowledgment. The authors thank Prof. K.S. Swami, for providing facilities. The financial assistance rendered by UGC (to VJ) and ICMR (to DCR) is gratefully acknowledged.     

Kälte als Auslöser einer Glykogen-Speicherung während der Oogenese vonMusca domestica

Summary InMusca domestica reared under standard conditions (21 °C), glycogen is stored in the oocyte towards the end of egg development. By 1–3 days exposure to lower temperatures (4 °C), a glycogen deposition can be released already in young follicles. This premature glycogen synthesis is not restricted to the ooplasm. Carbohydrates are also found in the nurse cells and the follicle epithelium. Similar results were formerly obtained by inhibition of oogenetic protein synthesis.

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Herrn Prof. Dr. Dr. h.c.Bernhard Rensch zum 70. Geburtstag gewidmet.     

pEGFPN1-dnEGFR对胃癌细胞的化疗增敏作用

目的研究人 EGFR显性负性突变体真核表达载体(pEGFPN1 dnEGFR)对人胃癌细胞株 SGC 7901和 NCI N87化疗敏感性的影响,并探讨其可能机制.方法 MTT法测定奥沙利铂对稳定转染 pEGFPN1 dnEGFR和 pEGFP N1载体的两种胃癌细胞的量效反应.奥沙利铂作用各组细胞24h后,RT PCR检测各组细胞中 Caspase 3和 CyclinD1的 mRNA表达情况;Westernblot检测各组细胞中 Caspase 3和 CyclinD1蛋白表达情况.结果转染 pEGFPN1 dnEGFR后,两种胃癌细胞对奥沙利铂的敏感性增加,奥沙利铂对 pEGFPN1 dnEGFR转染组细胞的增殖抑制率(VI)与对照组相比有显著提高(P<0.05).RT PCR显示 pEGFPN1 dnEGFR转染组细胞 CyclinD1mRNA表达较对照组下降,而 Caspase 3mRNA表达较对照组升高(P<0.05);Westernblot显示 pEGFPN1 dnEG FR转染组细胞 CyclinD1蛋白表达较对照组下降,而 Caspase 3蛋白表达较对照组升高(P<0.05).结论 EGFR显性负性突变体能提高胃癌细胞对化疗药物奥沙利铂的敏感性,其机制可能与 Caspase 3和 CyclinD1有关     

BRD7 regulates the insulin-signaling pathway by increasing phosphorylation of GSK3β

Reduced hepatic expression levels of bromodomain-containing protein 7 (BRD7) have been suggested to play a role in the development of glucose intolerance in obesity. However, the molecular mechanism by which BRD7 regulates glucose metabolism has remained unclear. Here, we show that BRD7 increases phosphorylation of glycogen synthase kinase 3β (GSK3β) in response to activation of the insulin receptor-signaling pathway shortly after insulin stimulation and the nutrient-sensing pathway after feeding. BRD7 mediates phosphorylation of GSK3β at the Serine 9 residue and this effect on GSK3β occurs even in the absence of AKT activity. Using both in vitro and in vivo models, we further demonstrate that BRD7 mediates phosphorylation of ribosomal protein S6 kinase (S6K) and leads to increased phosphorylation of the eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and, therefore, relieves its inhibition of the eukaryotic translation initiation factor 4E (eIF4E). However, the increase in phosphorylation of 4E-BP1 with BRD7 overexpression is blunted in the absence of AKT activity. In addition, using liver-specific BRD7 knockout (LBKO) mice, we show that BRD7 is required for mTORC1 activity on its downstream molecules. These findings show a novel basis for understanding the molecular dynamics of glucose metabolism and suggest the unique function of BRD7 in the regulation of glucose homeostasis.     

Effect of L-carnitine and stimulated lipolysis on muscle substrates in the exercising rat

To test the effect of L-carnitine on glycogen sparing when fat oxidation is increased, 100 mg/kg/d were given to rats orally for 3 days, resulting in 1.8-fold higher muscle carnitine levels. Even when FFA were raised by heparin-stimulated lipolysis, the rate of glycogen degradation was not reduced during exercise.     

Effect of L-carnitine and stimulated lipolysis on muscle substrates in the exercising rat

Summary To test the effect of L-carnitine on glycogen sparing when fat oxidation is increased, 100 mg/kg/d were given to rats orally for 3 days, resulting in 1.8-fold higher muscle carnitine levels. Even when FFA were raised by heparin-stimulated lipolysis, the rate of glycogen degradation was not reduced during exercise.     

The role of maternal parathyroids and vitamin D3 metabolites in fetal growth and the deposition of glycogen reserves in the maternal and fetal liver in rats]

Thyro-parathyroidectomy of pregnant Rats at 12.5 days of gestation decreased maternal liver glycogen on 21.5 days of gestation and fetal weight as well as fetal liver glycogen stores. The graft of one parathyroid gland or the injection of 1 alpha-hydroxycholecalciferol in these thyro-parathyroidectomized mothers increased their liver glycogen stores at 21.5 days of gestation. These treatments also markedly increased both fetal weight and fetal liver glycogen stores. It was concluded that maternal 1,25-dihydorxycholecalciferol, which is synthesized under the control of parathyroid hormone secretion, controls fetal growth and liver glycogen stores. The mechanism of these effects (direct or indirect) requires further investigations.     

Acid phosphatase activity of small intestine of mice after exposure to different doses of gamma rays

Summary Effect of whole-body radiation at 3 different dose levels on the activity of acid phosphatase was studied in the small intestine of Swiss albino mice. In all the 3 exposure groups the enzyme activity increased significantly at 24 h after irradiation; the time at which the maximum histological damage was seen. With the beginning of recovery the enzyme tended to decrease and gradually approached control values.     

Alpha-amylase inhibitor increases plasma 3-hydroxybutyric acid in food-restricted rats

The effect on energy metabolism of delayed absorption of starch by inhibition of -amylase was examined by considering levels of plasma glucose and 3-hydroxybutyric acid (3-OHBA) in rats. Addition of -amylase inhibitor (AI) to a high starch diet delayed the plasma glucose response after feeding: peak plasma glucose levels in the control group occurred 15 min after feeding, whereas in the AI group this peak did not occur until 30 min after. The total plasma glucose response was not different between the two groups. Plasma 3-OHBA levels 1 day after food restriction increased approximately five-fold in both groups. After 3 days of food restriction, the AI group maintained the same level of plasma 3-OHBA as after 1 day of food restriction, while the control group showed significantly decreased levels of 3-OHBA. After 3 days of food restriction, plasma insulin levels were significantly decreased in the AI group compared with the corresponding levels of the control group and with levels before the restriction. There was no significant difference in body weight between the two groups. These findings suggest that delayed hyperglycemia due to delayed absorption of starch following AI loading may attenuate insulin secretion, leading to altered metabolism of 3-OHBA during the delayed response to energy deficit.     

参附动员内皮祖细胞改善肝移植大鼠缺血再灌注损伤

目的 观察参附注射液对发生肝移植缺血再灌注损伤(IRI)的大鼠外周血中内源性内皮祖细胞(EPCs)的作用以及此作用对其肝脏功能的影响.方法 100只雌性SD大鼠随机分为3组:原位肝移植(0LT)+参附(SF)组,OLT对照组,假手术组.3组均于术后第1、4、7天取血液标本流式细胞术检测外周血内皮祖细胞数量及生化分析仪检测肝功能,观察胆汁分泌量,并取肝组织标本进行HE染色形态学观察肝脏损伤.结果 OLT+ SF组外周血中的EPCs在术后1天开始增加,第4天达到高峰并持续至第7天;并且在3个时间点上,OLT+ SF组的外周血EPCs数量较其它两组明显增加,具有统计学意义(p ＜0.01);OLT+ SF组在用药后IRI有所改善,较对照组有统计学差异(p＜0.05).结论 参附注射液能显著动员大鼠骨髓中的内源性EPCs进入外周血,修复损伤的肝血窦,改善微循环,进而改善肝移植术后的缺血再灌注损伤.