Changes of Hippocampal Noradrenergic Capacity in Stress Condition.

This study aimed to investigate the effects of chronic restraint stress (CRS) on the protein levels of dopamine-ß-hydroxylase (DBH), noradrenaline transporter (NET), vesicular monoamine transporter 2 (VMAT2) and brain-derived neurotrophic factor (BDNF), as well as the concentration of noradrenaline (NA) in the rat hippocampus. The investigated parameters were quantified by Western blot analyses and ELISA kits. We found that CRS increased the protein levels of DBH by 30 %, VMAT2 by 11 %, BDNF by 11 % and the concentration of NA by 104 %, but decreased the protein levels of NET by 16 % in the hippocampus of chronically stressed rats. The molecular mechanisms by which CRS increased the hippocampal NA level are an important adaptive phenomenon of the noradrenergic system in the stress condition.

Antioxidant status and sex hormones in women with complex endometrial hyperplasia.

Endometrial tissue is under a strong influence of sex hormones. These hormones are considered as developmental factors of endometrial hyperplasia and endometrial cancer. We examined the influence of gonadotropins (follicle-stimulating and luteinizing hormone) and sex hormones (estradiol, progesterone) on oxidant/antioxidant parameters in blood and endometrial tissue of women with complex endometrial hyperplasia. In blood, superoxide dismutase activity was significantly higher in luteal phase and postmenopause compared to the follicular phase. A significant phase-related difference of glutathione peroxidase and glutathione reductase activity was recorded in the endometrium. Both enzymes had lower activity in luteal phase and postmenopause compared to the follicular phase. The linear regression analysis of individual hormonal variables against antioxidant parameters showed negative correlation between glutathione peroxidase activity and gonadotropin concentrations in the endometrium. The regression of hyperplastic to normal endometrium is the purpose of conservative treatment based on administration of progestogens or gonadotropin-releasing hormone analogues. Our findings indicate that gonadotropins influence the antioxidant enzymes activity in women with complex endometrial hyperplasia, which may affect disease development. Further studies are needed to clarify the molecular basis of hormone action on antioxidant system that may potentially initiate a development of treatments based on redox-dependent mechanism.

Antioxidant status in blood of gynaecological patients: influence of diagnosis and reproductive factors.

Cancer of the reproductive tract is an important cause of morbidity and mortality among women worldwide. In this study we evaluated the influence of diagnostic categories, age and reproductive factors on antioxidant enzymes and lipid hydroperoxides in the blood of gynaecological patients diagnosed with endometrial polyp, myoma, hyperplasia simplex, hyperplasia complex and endometrial adenocarcinoma. Multivariate regression analysis was used to assess the association of diagnosis, age, parity, abortions and abnormal uterine bleeding with the examined parameters. Diagnosis provided the best predictive model for superoxide dismutase, catalase and glutathione peroxidase activities, and also for the lipid hydroperoxide level. Abortions fitted the best predictive model for superoxide dismutase activity. A significant correlation was also found between the predictor variables themselves. This study showed that reproductive and other factors may be associated, at least partially, with antioxidant capacity and ability to defend against the oxidative damage in gynaecological patients with various diagnoses.

Effect of low temperature cultivation on insulin secretory of human pancreatic islets.

The experiment compared the physiological function (insulin secretory capacity) and membrane integrity of human adult pancreatic islets incubated in culture at 37°C and 24°C. Pancreatic tissue was digested with Collagenase XI, using a non-automated method. Cultures were incubated at 37°C and 24°C. Secretory capacity of the islets is determined by measuring of the stimulation index (SI) on the 1st, 3rd and 7th day of cultivation. Membrane integrity of the islets was determined by dithizone staining. Both groups of examined cultures show a slight increase in SI during the incubation. However islets incubated at 24°C show higher SI values than those incubated at 37°C on the 1st, 3rd and 7th day of incubation. And on the first day of incubation, this difference was statistically significant (p <0.05). Islets incubated at 37°C showed preservation of membrane integrity, the islets are regular spherical shape, while those incubated at 24°C lose such an organization. During the seven-day cultivation, islets incubated at a standard temperature of 37°C show less preserve physiological functions in relation to cultures incubated at 24°C, but islets incubated at 37°C show more regular morphological forms.

Effect of chronic forced running on gene expression of catecholamine biosynthetic enzymes in stellate ganglia of rats.

The sympathoneural system has a profound influence on the heart function. Sympathetic neurons are the major contributors to the huge rise of circulating noradrenaline (NA) level in response to stressful stimuli. Treadmill training in rats is forced exercise which has the propensity to induce both psychological and physical stress. The aim of this study is to examine how chronic forced running (CFR) affects the expression of catecholamine biosynthetic enzymes (tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT)) and cAMP response element-binding (CREB) in stellate ganglia, as well as the concentrations of catecholamines, adrenocorticotropic hormone (ACTH) and corticosterone (CORT) in the plasma of rats. Also, we investigated how the additional acute immobilization stress changes the mentioned parameters. The rat training program consisted of 12 weeks running on a treadmill (20 m/min, 20 min/day). We found that CFR increases TH and DBH mRNA and protein levels in stellate ganglia, which is followed by increased NA concentration in the plasma. CFR reduces the level of PNMT mRNA, while the level of PNMT protein remains unchanged in stellate ganglia. The increased expression of TH and DBH genes positively correlates with the expression of CREB in stellate ganglia and with plasma ACTH level, while reduced level of PNMT mRNA in stellate ganglia correlates with reduced plasma CORT level. The additional acute immobilization stress increased gene expression of catecholamine biosynthetic enzymes in stellate ganglia, as well as catecholamines, ACTH and CORT levels in the plasma. The results presented here suggest that the continuous increase of the noradrenaline biosynthetic enzyme expression in stellate ganglia due to CFR may play a role in growing risk of cardiovascular diseases.

Regional differences in antioxidative response of rat brain after cranial irradiation.

In order to examine if differences in activity and inducibility of antioxidative enzymes in rat cerebral cortex and hippocampus are underlying their different sensitivity to radiation, we exposed four-day-old female Wistar rats to cranial radiation of 3 Gy of gamma-rays. After isolation of hippocampus and cortex 1 h or 24 h following exposure, activities of copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT) were measured and compared to unirradiated controls. MnSOD protein levels were determined by SDS-PAGE electrophoresis and Western blot analysis. Our results showed that CuZnSOD activity in hippocampus and cortex was significantly decreased 1 h and 24 h after irradiation with 3 Gy of gamma-rays. MnSOD activity in both brain regions was also decreased 1 h after irradiation. 24 h following exposure, manganese SOD activity in hippocampus almost achieved control values, while in cortex it significantly exceeded the activity of the relevant controls. CAT activity in hippocampus and cortex remained stable 1 h, as well as 24 h after irradiation with 3 Gy of gamma-rays. MnSOD protein level in hippocampus and cortex decreased 1 h after irradiation with 3 Gy of gamma-rays. 24 h after exposure, MnSOD protein level in cortex was similar to control values, while in hippocampus it was still significantly decreased. We have concluded that regional differences in MnSOD radioinducibility are regulated at the level of protein synthesis, and that they represent one of the main reasons for region-specific radiosensitivity of the brain.

Alterations in hippocampal antioxidant enzyme activities and sympatho-adrenomedullary system of rats in response to different stress models.

The study deals with activity of three antioxidant enzymes, copper, zinc-superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), catalase (CAT) in hippocampus of rats, following the exposure to single chronic (individual housing or forced swimming) and acute (immobilization or cold) stress, as well as to combined chronic/acute stress. In addition, plasma noradrenaline (NA) and adrenaline (A) concentrations were measured in the same stress conditions, because their autooxidation can add to the oxidative stress. We observed that i) long-term social isolation and repeated forced swimming had minor effects on plasma catecholamines, but in the long-term pretreated groups, acute stressors caused profound elevation NA and A levels, ii) chronic stressors activate antioxidant enzymes, iii) acute stressors decrease catalase activity, their effects on CuZnSOD appear to be stressor-dependent, whereas MnSOD is not affected by acute stressors, and iv) pre-exposure to chronic stress affects the antioxidant-related effects of acute stressors, but this effect depends to a large extent on the type of the chronic stressor. Based on both metabolic and neuroendocrine data, long-term isolation appears to be a robust psychological stressor and to induce a "priming" effect specifically on the CuZnSOD and CAT activity.

Adaptive significance of amylase polymorphism in Drosophila. X. Analysis of alpha-amylase activity of two amylase variants in individual Drosophila subobscura flies.

Experiments were designed to estimate the variation of alpha-amylase activity in Drosophila subobscura individuals homozygous for AmyS and AmyF alleles at the Amy locus. The measurements of enzyme activities in six groups of male progenies determined in each individual have shown that degree of variation differs between S and F strains. Variability of amylase activity among male progenies of S strain was substantially greater, which also had significantly higher specific amylase activity than in F strain. The analysis of amylase activity variance showed that this variance among the males is 40 times, and among the females 2.7 times smaller in F than in S strain.