Effects of progesterone and estradiol benzoate on glutathione dependent antioxidant enzyme activities in the brain of female rats.

The activities of glutathione dependent antioxidant enzymes were measured in subcellular fractions of whole brain homogenates prepared from ovariectomized (OVX) female rats, untreated or treated 2 h or 24 h prior to sacrifice with a single dose of 2 mg progesterone (P) or 5 micrograms estradiol benzoate (EB). Glutathione peroxidase (GSH-Px) activity was not changed following systemic administration of EB, but P increased GSH-Px in the brain of OVX rats 24 h after the treatment. The activity of glutathione reductase (GR) was suppressed by EB short time, only 2 h following treatment, whereas P increased the enzyme activity 24 h after treatment. On the other hand, the activities of catalase (CAT) and glutathione-S-transferase (GST) were not changed following systemic administration of EB or P. The present work was carried out to study the involvement of ovarian steroids, especially P, in the control of GSH-Px and GR activities, and our results suggest that oxidative stress in the brain of female rats may be modulated by the level of progesterone.     

Effects of olive oil on superoxide dismutase activity in the brain of newborn and young female rats

Changes in the activity of brain antioxidant superoxide dismutases (SOD) were followed in newborn and young female rats 8, 15, 30, 45, 60 and 75 days after birth treated with olive oil. In newborn rats, the content of brain cytosol SOD (CuZnSOD) and mitochondrial SOD (MnSOD) decreased after treatment with olive oil. However, in the brain of rats aged 8 days this effect was lost. The suppressive effect of olive oil on these enzymes reappeared again in 15-day-old rats. In rats aged one month, only the activity of CuZnSOD was reduced after olive oil treatment. In the brain of rats aged 45, 60 and 75 days, neither MnSOD nor CuZnSOD were affected by olive oil. The different effects of olive oil on the brain SOD, during ontogeny suggest that profound changes in the susceptibility of nervous tissue antioxidant enzymes to olive oil take place during sexual maturation.     

雌二醇、壬基酚、多氯联苯、镉和锌暴露对唐鱼体内超氧化物歧化酶活性的影响

目的 研究雌二醇(E2)、壬基酚(NP)、多氯联苯(PCBs)、镉(Cd2+)和锌(Zn2+)单独以及联合暴露对唐鱼体内SOD酶活力的影响.方法设计不同浓度的单一物质及混合物对唐鱼14 d暴露染毒,定量测定7、14d体内SOD酶活力的变化.结果 ①低浓度E2处理唐鱼7d可诱导SOD活性显著上升,时间延长、浓度升高时SOD活性无明显变化;②低浓度NP对SOD活性没有明显的影响,高浓度NP使SOD活性极显著上升;③中高浓度组PCBs处理7、14 d,低浓度组PCBs处理14 d时SOD活性被抑制,抑制程度随着时间的延长和浓度的升高有增强的趋势;④Cd2+、Zn2+各浓度组都对唐鱼体内的SOD活性产生了一定的抑制作用,并且抑制程度随着时间的延长而加深.结论 E2、NP、PCBs、Cd2+、Zn2+对唐鱼的SOD酶活力有明显影响,它们单独作用时的SOD活性与暴露浓度之间存在良好的剂量-效应关系.联合作用效应与暴露时间和(或)各物质浓度有关,大部分表现为毒性增强.     

Effects of estradiol and progesterone on scent-marking behavior of female rats

The effect of estradiol and progesterone on scent-marking behavior of the female rat is reported. Estradiol followed by progesterone injection to ovariectomised rats results in an increase in marking rates. This suggests an endocrine base to the changes in scent-marking behavior that are known to occur with the rat estrous cycle.     

Effects of estradiol and progesterone on early embryonic development in aging rats

Regularly cyclic, middle-aged female rats exhibit a decreased incidence of fertility, and those females that are fertile produce small litters. These decreases in fertility and litter size are associated with reduced numbers of normal blastocysts formed and implanted, suggesting that pre- and/or peri-implantation failures may be the causes for these aging-related reproductive declines. The present study examined the relationships and influence of circulating estradiol (E2) and progesterone (P) levels on early embryonic development and implantation in middle-aged rats. Serial blood samples obtained from cannulated, middle-aged pregnant rats revealed minor decreases in plasma P and increases in E2 levels during Days 2-4 of pregnancy, compared to young pregnant rats, resulting in significantly (p less than 0.001) decreased plasma P/E2 ratios. These alterations in endogenous hormone secretion in middle-aged pregnant rats were associated with fewer normal blastocysts on Day 5 of pregnancy and reduced numbers of normally implanting embryos. Correlation analysis further revealed a significant (p less than 0.05) inverse relationship between mean circulating E2 levels and numbers of normal conceptuses on Day 12 of gestation. Moreover, s.c. administration of P implants (in Silastic) to middle-aged pregnant rats increased serum P levels by about 34-40 ng/ml, and significantly (p less than 0.05) reduced the incidence of abnormal embryos before implantation. In contrast, treatment with E2 minipumps produced a sustained rise in serum E2 (by about 7-15 pg/ml) and resulted in the complete absence of embryos in the reproductive tracts by Day 5 of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of estradiol and progesterone on rat uterine ribonuclease inhibitor activity

The effects of estradiol (E2) and progesterone on rat uterine RNase inhibitor activity were investigated. RNase inhibitor activity was found to be most prominent in nuclear and cytosolic fractions of the uterus. Uterine RNase inhibitor activity in the 45,000 x g cytosolic fraction was stimulated by E2 over a 6-24 hr treatment period. Progesterone did not produce a significant change in the uterine cytosolic RNase inhibitor activity during the same period.     

Serum superoxide dismutase 3 (extracellular superoxide dismutase) activity is a sensitive indicator of Cu status in rats

Sensitivity of the assay for Cu,Zn superoxide dismutase 3 (SOD3), the predominant form of SOD in serum, can be increased, and interferences caused by low-molecular-weight substances in the serum can be reduced by conducting the assay at pH 10 with xanthine/xanthine oxidase and acetylated cytochrome c (cyt c) as superoxide generator and detector, respectively. Serum SOD3 activity was assayed under these conditions in an experiment where weanling, male rats were fed diets for 6 weeks containing 3, 5 and 15 mg Zn/kg with dietary Cu set at 0.3, 1.5 and 5 mg Cu/kg at each level of dietary Zn. Serum SOD3 responded to changes in dietary Cu but not to changes in dietary Zn. A second experiment compared serum SOD3 activity to traditional indices of Cu status in weanling, male and female rats after they were fed diets containing, nominally, 0, 1, 1.5, 2, 2.5, 3 and 6 mg Cu/kg for 6 weeks. Serum SOD3 activity was significantly lower (P < .05) in male rats fed diets containing 0 and 1 mg Cu/kg and female rats fed diet containing 0 mg Cu/kg compared with rats fed diet containing 6 mg Cu/kg. These changes were similar to changes in liver Cu concentrations, liver cyt c oxidase (CCO) activity and plasma ceruloplasmin in males and females. Serum SOD3 activity was also strongly, positively correlated with liver Cu concentrations over the entire range of dietary Cu concentrations (R(2) = .942 in males, R(2) = .884 in females, P < .0001). Plots of serum SOD3 activity, liver Cu concentration, liver CCO activity and ceruloplasmin as functions of kidney Cu concentration all had two linear segments that intersected at similar kidney Cu concentrations (18-22 microg/g dry kidney in males, 15-17 microg/g dry kidney in females). These findings indicate that serum SOD3 activity is a sensitive index of Cu status.     

Effects of chlorpromazine and estradiol benzoate on prolactin secretion in gonadectomized male and female rats.

The effects of chlorpromazine (CPZ) and estradiol benzoate (EB) on serum prolactin (PRL) levels were studied in gonadectomized male and female rats. In both sexes CPZ (25 mg/kg body weight) produced an elevation of PRL when measured 2 hr after the injection, but the elevated levels were higher in ovariectomized rats than in orchidectomized rats. These results reconfirm a sexual difference in the regulatory mechanism of PRL secretion in response to the dopamine receptor blocker. Pretreatment with 5 microgram EB 48 hr before CPZ injection abolished this sexual difference in serum PRL concentration.     

Effect of estradiol and progesterone on UDPgalactose pyrophosphatase activity in the endometrium of ovariectomized rats.

Rat endometrium was found to contain a UDPgalactose pyrophosphatase for the hydrolysis of UDPgalactose into galactose 1-phosphate and UMP. The adminstration of 17beta-estradiol to ovariectomized rats resulted in a significant decrease in the activity of the enzyme in endometrium while have little effect on that in myometrium. The response was linear with the dose of estradiol and as little as 0.07 mug per 100 g body weight produced maximum inhibition of the enzyme. Progesterone on its own had little effect on the enzyme activity but in combination with estradiol, it effectively prevented the inhibitory effect of estradiol. This inhibitory effect of estradiol on the activity of UDPgalactose pyrophosphatase may function in the regulation of glycoprotein biosynthesis in endometrium.     

Effects of estradiol and progesterone on the sensitivity to pain and on morphine-induced antinociception in female rats

Long-term ovariectomized (OVX) rats were exposed to 2- or 14-day replacement with pellets made of cholesterol (CHOL), estradiol (E2), progesterone (P4), or a combination of E2 and P4. Following the treatment with steroids the antinociceptive effect of morphine (5 mg/kg,sc) was measured by a hot-plate method. Pellets of E2 (0.5 and 5%) caused dose- and time-dependent reductions of morphine-induced antinociception as compared with OVX rats treated with CHOL pellets. Moreover, OVX rats pretreated with E2 pellets had decreased basic sensitivity to nociceptive stimulus (hyperalgesia). Treatment for 2 and 14 days with 75% P4 pellets produced significant reduction of MOR antinociception. The low dose of P4 (10% pellet) did not change the effect of MOR on Day 2 but significantly increased the antinociceptive effect of MOR on Day 14. Replacement of OVX rats with one 0.5% E2 pellet plus one 10% P4 pellet resulted in marked inhibition of the antinociceptive effect of MOR on Day 2 as well as on Day 14. Central injection 30 min before MOR of either LHRH antagonist or the antiserum against LHRH into OVX rats pretreated for 14 days with both steroids had no effect on the degree of the antinociception. The results suggest that the effects which ovarian steroids exert on opioid systems vary according to the dose, the duration of treatment, and the type of steroid administered.     

Effects of catechin and epicatechin on superoxide dismutase and glutathione peroxidase activity,in vivo

Abstract

Objectives

The objective of this study was to investigate the effects of catechin and epicatechin on the activity of the endogenous antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) (as well as the total antioxidant capacity (TAC)) of rats after intra-peritoneal (i.p.) administration.

Methods

Twenty-four Wistar rats were randomly divided into two groups: the experimental group which was administered daily with a 1:1 mixture of epicatechin and catechin at a concentration of 23 mg/kg body weight for 10 days and the control group which was injected daily with an equal amount of saline. Blood and urine samples were collected before and after the administration period, as well as 10 days after (follow-up).

Results

Intra-peritoneal administration of catechins led to a potent decrease in GPx levels and a significant increase in SOD levels. TAC was significantly increased in plasma and urine. Malonaldehyde levels in urine remained stable. In the animals treated with catechins, SOD activity showed a moderate negative correlation with GPx activity.

Discussion

Boosting the activity of the antioxidant enzymes could be a potential adjuvant approach for the treatment of the oxidative stress-related diseases.     

Production of superoxide and activity of superoxide dismutase in rabbit epididymal spermatozoa

Mature rabbit spermatozoa from the cauda epididymidis suspended in potassium Tris phosphate buffer at 24 degrees C produced O2.-, as measured by reduction of acetylated ferricytochrome c, with an intrinsic rate of 0.20 nmol/min per 10(8) cells. This rate increased to 1.80 nmol/min per 10(8) cells in the presence of 10 mM cyanide. These spermatozoa contain 2.8 units per 10(8) cells of superoxide dismutase activity, 95% of which is sensitive, and 5% of which is insensitive, to cyanide inhibition. These activities correspond to the cytosolic Cu-Zn form and the mitochondrial Mn form of the dismutase, respectively. Only the cyanide-sensitive form is released from the sperm on hypo-osmotic treatment or sonication. Hypo-osmotically treated rabbit epididymal spermatozoa produced O2.- with an intrinsic rate of 0.24 nmol/min per 10(8) cells, which increased to 0.58 nmol/min per 10(8) cells in the presence of 10 mM cyanide. Both intact and hypo-osmotically treated cells react with O2.- in a second order reaction as inferred from the hyperbolic dependence on cell concentration of O2.- production rate in both the absence and presence of cyanide. The second order rate constant for this reaction with intact cells, kS, was calculated to be 22.9 X 10(-8) (cells/ml)-1 min-1 in its absence. For hypo-osmotically treated cells, the values of kS were 10.8 X 10(-8) (cells/ml)-1 min-1 and 8.2 X 10(-8) (cells/ml) -1 min-1, respectively. Since hypo-osmotically treated cells have lost much of their plasma membrane, the lower value of kS for the treated cells implies that this membrane is one site of reaction of O2.- with the cells. The increase in kS in the presence of cyanide, which inhibits superoxide dismutase and so increases O2.- production, suggests that the cells become more reactive with O2.- as its production rate increase, as would be expected for the occurrence of radical chain oxidation. This in turn suggests that superoxide dismutase plays a major role in protecting rabbit sperm against damage from lipid peroxidation.     

Factors reducing the superoxide dismutase activity of the liver of rats with Pliss lymphosarcoma

The procedures for isolation and purification of Cu/Zn superoxide dismutase (SOD) from small amounts of rat liver at different stages of Pliss lymphosarcoma growth were developed. Two stages of tumour growth were distinguished. At the first stage (4-5th day after reinoculation) the intensity of optical (680 nm) and EPR spectra of SOD was decreased, on the average, to 30%, while at the second stage--by 40% at 680 nm and by 32%, at 260 nm. The intensity of the EPR spectra was also diminished by 40% as compared to the control. It was assumed that at initial stages of tumour growth the decrease of the SOD activity is mainly due to the reduction of enzyme Cu, while at the second stage--to the decrease of the protein content. In all probability, the observed changes are induced by the activation of lipid peroxidation involving active O2 species. The second stage is associated with the superoxide-induced impairment of the function of nucleic acids involved in protein biosynthesis.     

Antioxidant superoxide dismutase activity in obese children

The aim of the study was to evaluate the antioxidative Cu/Zn-SOD (superoxide dismutase) response to obesity-related stress in obese children compared to a similar-aged control group. Forty-eight exogenic obese children and 11 healthy children were compared for red cell Cu/Zn-SOD, glucose, and lipid profiles and the relations between the were investigated. Antioxidant response as Cu/Zn-SOD was significantly higher in the obese group (p<0.05). Although glucose and lipid levels were statistically higher in the obese group, a certain relation with the SOD level was not established in childhood. This is the first study showing the oxidative stress caused by obesity and related antioxidative response even in the childhood period. Interventions, including diet modifications, should be kept in mind to diminish the obesity-related oxidative stress from the childhood period.     

Effects of estradiol benzoate in combination with dihydrotestosterone on postejaculatory vocalization and refractory period in castrated male rats

The objective of this experiment was to compare the effects of estradiol ben-zoate (EB) treatment with those of testosterone propionate (TP) on the postejaculatory vocalization and refractory period in castrated dihydrotestosterone (DHT)-treated male rats. Twelve reliable maters were tested, castrated, and then treated with subcutaneous implants of DHT and daily injections of either 200 μg of TP (N = 6) or 200 μg of EB (N = 6). Testing continued weekly for 9 weeks with treatments interchanged after the fourth week. EB treatment resulted in: (1) a reduction in the number of males that vocalized, (2) a reduction in the duration of vocalization, and (3) the exhibition of extraordinarily abbreviated postejaculatory refractory periods by a few males. It was suggested that high doses of estradiol act to counter inhibitory processes during the refractory period.     

Effect of estradiol benzoate and clomiphene on tyrosine hydroxylase activity and on luteinizing hormone and prolactin levels in ovariectomized rats

The effects of estradiol benzoate (EB) on tyrosine hydroxylase (TH) activity in the medial basal hypothalamus (MBH) and on plasma levels of luteinizing hormone (LH) and prolactin were studied in long-term ovariectomized rats. Administration of 10 μg EB produced significant elevation of TH activity on Days 1 and 3 following injection. LH levels were significantly lower than controls throughout the three day treatment period, although there was a significant increase from Day 1 to Day 2. TH activity and LH levels were inversely related throughout the experimental period. Clomiphene (15 μg/rat/day), a purported estrogen antagonist, was administered over a period of three days to control and EB-treated rats to determine whether the effect of EB on plasma LH levels was causally related to changes in TH activity. In rats receiving both EB and clomiphene, TH activity was lower and plasma LH was higher than after EB alone. The results support the hypothesis that the feedback effects of estradiol on LH release involve an action on the tuberoinfundibular dopaminergic (TIDA) neurons of the MBH and that clomiphene can oppose the inhibitory effect of estradiol on LH release by directly inhibiting TIDA neuron activity. Furthermore, EB-induced release of prolactin does not appear to involve detectable changes in the activity of TIDA neurons.     

Temperature dependence of superoxide dismutase activity in plankton

The effect of temperature (from 1 to 37 °C) on in vitro effective superoxide dismutase (SOD) activity of several organisms was investigated and compared. Antarctic plankton, cultures of the alga Nannochloropsis sp., and the cyanobacterium Synechococcus strain WH 7803, and pure bovine erythrocyte SOD was studied. It was found that in all cases SOD activity increased with decreasing temperature within the temperature range assayed, in the Polar as well as the temperate plankton cells. This behavior of SOD is counterintuitive in terms of our experience when looking at enzyme activity or any other chemical reaction. We suggest a theoretical explanation for this apparently odd behavior. The advantage of such behavior is that the same amount of antioxidant will act better under low temperatures when reactive oxygen species (ROS) increase. Moreover, this protective process would act in vivo at a faster pace than the ex novo enzyme synthesis.