• Biomolecules & Therapeutics
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• 제9권2호
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• pp.119-124
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• 2001

In order to determine the role of dehydroepiandrosterone (DHEA), the important sex-steroid hormone precursor, in vascular reactivity in rats, animals were treated for two weeks with DHEA or sex hormones, and the vascorelaxant and contractile responses of isolated aorta were examined. DHEA diminished the acetylcholine (ACh)-induced relaxation in female rats, while the drug was without effect in males. Testoterone lowered the vasorelaxant activity to ACh in either sex. 17$\beta$-Estradiol enhanced ACh-induced vasorelaxation in male rats, but this female sex hormone did not influence in females. In male rats, the androgen receptor antagonist flutamide also enhanced vasorelaxant action of ACh. When the male rat aorta was incubated in vitro with a nitric oxide (NO) synthase inhibitor L-NAME, phenylephrine-induced contraction was greatly potentiated in DHEA-pretreated rats compared to control ones. The present results suggest that DHEA stimulates mainly androgen in female, but both androgen and estrogen in male rats. The participation of NO In the modulation of vascular reactivity with pretreated DHEA was also considered.

• Journal of Nutrition and Health
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• 제38권5호
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• pp.364-372
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• 2005

This study is designed to examine the effects of dietary supplementation with vitamin E and dehydroepiandrosterone (DHEA) on the formation of preneoplastic lesions in diethylnitrosamine (DEN) induced rat hepatocarcinogenesis. All Weaning male Sprague-Dawley rats were initiated by a single dose of DEN (200mg/kg body weight), subjected to two­thirds partial hepatectomy 3 weeks later and were sacrificed 8 weeks after DEN initiation. Two weeks after initiation, rats were fed Purina purified rodent diet 5053 (Ralston Purina Rat chow, USA) with $1.5\%$ (15,000 IU/kg diet) vitamin E, $0.5\%$ DHEA and both of those supplemented diet for 6 weeks. Placental glutathione S-transferase (GST-P) positive foci, the activities of catalase, total-glutathione peroxidase (GPx) , glutathione reductase (GR), glutathione S-transferase (GST) and thiobarbituric acid reactive substances (TBARS) contents were decreased significantly by vitaimin E supplement. On the other hand GST-P positive foci number, Cu/Zn-superoxide dismutase (SOD) and glucose 6-phosphatase (G6Pase) activities weren't changed by vitamin E supplement. It might suggest that protective effect of vitamin E against hepatocarcinogens is not involved in the formation of the GST-P positive foci but related to the expansion of that. It seemed that vitamin E supplement helped endogenous defense system in carcinogenesis by decreasing TBARS contents, $H_2O_2$, organic peroxides. Therefore, vitamin E seemed to protect cell from free radical damage in carcinogenesis. By DHEA supplement liver weight and liver/body ratio were increased, the area and number of GST-P positive foci, the activities of catalase, GR, total GPx, GST and the TBARS contents were decreased significantly. On the other hand Cu/Zn-SOD and G6Pase activities weren't changed by DHEA supplement. In hepatocarcinogenesis the activities of antioxidant enzymes weren't increased by DHEA supplement. DHEA did not increase the oxidative stress, while DHEA seems to have anticarcinogenic effect in rats hepatocarcinogenesis.

• Biomolecules & Therapeutics
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• 제17권1호
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• pp.57-61
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• 2009

This study examined whether or not a pretreatment with dehydroepiandrosterone (DHEA) has an effect on indomethacin-induced gastric mucosal damage. The DHEA group, male Sprague-Dawley rats, was administrated with DHEA orally at a dose of 4 mg/day for one week before inducing gastritis with indomethacin (50 mg/kg, p.o.). Histological assay, lipid peroxidation assay, superoxide dismutase (SOD), glutathione peroxidase (GPx) and Catalase activities were determined. Interestingly, it was found that the DHEA pretreatment attenuated the gastric lesion area induced by indomethacin. Rather, the pretreatment with high dose of DHEA led to submucosal edema, leukocyte infiltration in submucosa and mucosal necrosis. The levels of MDA in the DHEA pretreatment were also higher than those in the rats given with vehicle pretreatment. This suggests that the DHEA pretreatment deteriorates severe inflammation in indomethacin-induced gastritis. DHEA supplementation significantly increased SOD activity in the gastric mucosa. However, the catalase and GPx activities were not altered by DHEA. The co-administration of DHEA with an indomethacin might not offer a protective effect against the acute gastritis induced by indomethacin.

• Archives of Pharmacal Research
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• 제22권5호
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• pp.474-478
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• 1999

Modulation of unscheduled DNA synthesis by dehydroepiandrosterone (DHEA) after exposure to various chemical carcinogens was investigated in the primary rat hepatocytes. Unscheduled DNA synthesis was induced by treatment of such direct acting carcinogens as methly methanesulfonate (MMS) and ethyl methanesulfonate (EMS) or procarcinogens including benzo(a)pyrene (BaP) and 7, 12-dimethylbenz(a)anthracene (DMBA). Unscheduled DNA synthesis was determined by measuring [methyl-3H]thymidine radioactivity incorporated into nuclear DNA of hepatocytes treated with carcinogens in the presence or absence of DHEA. Hydroxyurea $(5{\times}10^{-3} M)$was added to growth medium to selectively suppress normal replication. DHEA at concentrations ranging from $(1{\times}10^{-6} M)$ to$(5{\times}10^{-4} M)$ did not significantly inhibit unscheduled DNA synthesis induced by either MMS $(1{\times}10^{-4} M)$ or EMS $(1{\times}10^{-2} M)$. In contrast, DHEA-significantly inhibited unscheduled DNA synthesis induced by BaP $(6.5{\times}10^{-5} M)$ and DMBA.$(2{\times}10^{-5} M)$. DHEA-induced hepatotoxicity in rats was examined using lactate dehydrogenase (LDH) release as an indicator of cytotoxicity. DHEA exhibit no significant increase in LDH release compared with the control at 18 h. These data suggest that nontoxic concentration of DHEA does not affect the DNA excision repair process, but it probably influence the enzymatic system responsible for the metabolic activation of procarcinogens and thereby decreases the amount of the effective DNA adducts formed by the ultimate reactive carcinogenic species.

• 운동영양학회지
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• 제24권4호
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• pp.24-27
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• 2020

[Purpose] Dehydroepiandrosterone (DHEA) administration reportedly recovers osteoporosis, a bone disorder associated with bone deficiency in postmenopausal women. However, the physiological mechanism of DHEA in osteoporosis remains elusive, especially in terms of intestinal calcium absorption. Therefore, we investigated the effect of DHEA administration on calcium absorption in ovariectomized (OVX) female rats using an estrogen receptor antagonist. [Methods] Female Sprague-Dawley rats (n=23, 6 weeks old) were randomized into three groups: OVX control group (OC, n=7), OVX with DHEA treatment group (OD, n=8), and OVX with DHEA inhibitor group (ODI, n=8) for 8 weeks. [Results] Intestinal calcium accumulation, as well as the rate of absorption, demonstrated no significant differences during the experimental period among investigated groups. The bone mineral density (BMD) of the tibia at the proximal metaphysis was higher in the OD group than that in the OC group (p<0.05); however, BMD of the ODI group showed no significant difference from investigated groups. Furthermore, the BMD of the tibia at the diaphysis did not significantly differ among these groups. [Conclusion] We revealed that DHEA administration does not involve intestinal Ca absorption, although this treatment improves BMD levels in OVX rats. These observations indicate that the effect of DHEA on the bone in postmenopausal women is solely due to its influence on bone metabolism and not intestinal calcium absorption.

• 대한간호학회지
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• 제39권5호
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• pp.632-640
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• 2009

Purpose: The purpose of this study was to examine the effect of DHEA (Dehydroepiandrosterone) on muscle weight and Type I and II fiber cross-sectional area of affected and unaffected hindlimb muscles in rats with neuropathic pain induced by unilateral peripheral nerve injury. Methods: Neuropathic pain was induced by ligation and cutting of the left L5 spinal nerve. Adult male Sprague-Dawley rats were randomly assigned to one of two groups: The DHEA group (n=10) had DHEA injections daily for 14 days, and the Vehicle group (n=10) had vehicle injections daily for 14 days. Withdrawal threshold, body weight, food intake and activity were measured every day. At 15 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles were dissected from the both hindlimbs. Body weight, food intake, activity, muscle weight and Type I, II fiber cross-sectional area of the dissected muscles were measured. Results: The DHEA group showed significant increases (p<.05), as compared to the vehicle group for muscle weight of the unaffected plantaris, and in Type II fiber cross-sectional area of the gastrocnemius muscle. The DHEA group demonstrated a higher pain threshold than the vehicle group whereas total diet intake and activity score were not significantly different between the two groups. Conclusion: DHEA administration for 14 days attenuates unaffected plantaris and gastrocnemius muscle atrophy.

• 대한간호학회지
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• 제39권3호
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• pp.321-328
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• 2009

Purpose: The purpose of this study was to determine the effect of Dehydroepiandrosterone(DHEA) administration alone or exercise combined with DHEA before steroid treatment on rat hindlimb muscles. Methods: Male Sprague-Dawley rats were assigned to one of three groups: a steroid group(S, n=10) that had no treatment for 7 days before steroid treatment; a DHEA-steroid group(DS, n=8) that had 0.34 mmol/kg/day DHEA injection once a day for 7 days before steroid treatment and an exercise+DHEA-steroid group(EDS, n=9) that ran on the treadmill combined with 0.34 mmol/kg/day DHEA injection for 7 days before steroid treatment. At 15 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles were dissected. Body weight, food intake, muscle weight, myofibillar protein content and cross-sectional area of the dissected muscles were determined. Results: The DS group showed significant increases(p<.05) as compared to the steroid group in body weight, and muscle weight of gastrocnemius muscles. The EDS group showed significant increases(p<.05) as compared to the S group in body weight, muscle weight, myofibrillar protein content, and Type II fiber cross-sectional area of soleus, plantaris and gastrocnemius muscles. Conclusion: Exercise combined with DHEA administration before steroid treatment prevents steroid induced muscle atrophy, with exercise combined with DHEA administration being more effective than DHEA administration alone in preventing muscle atrophy.

• The Korean Journal of Physiology and Pharmacology
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• 제10권2호
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• pp.79-83
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• 2006

We evaluated therapeutic and preventive properties of dehydroepiandrosterone (DHEA), a weak androgenic steroid, against isoproterenol-induced cardiomyopathy. The cardiomyopathy was induced by daily i.p. administration of isoproterenol to rats for five days. One group of rats were given with daily s.c. for 5 days during isoproterenol and the other group with daily s.c. DHEA for total 10 days, including 5 days before and during isoproterenol. The animals were killed after each treatment, and cardiac muscle failure was evaluated using histopathologic examination and biochemical indices. DHEA was found to reduce the damaged area and inhibit the elevation in the serum levels of glutamic oxaloacetic transaminase (SGOT), lactate dehydrogenase (LDH), skeletal muscle creatine kinase (CK) and heart creatine kinase (CK-MB) induced by isoproterenol. We also assayed widely used oxidative stress parameters, including thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase and glutathion peroxidase (GPx). DHEA decreased the escalated level of TBARS and enhanced the anti oxidant defense reaction with an increase in Mn-SOD and Cu/Zn-SOD. On the other hand, the treatment with DHEA did not affect catalase and GPx activity. The present study indicates that DHEA has a therapeutic and preventive effect against isoproterenol-induced cardiomyopathy and its effects may depend largely on the increase in SOD activity.

• Nutrition Research and Practice
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• 제2권2호
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• pp.80-84
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• 2008

Beneficial effects of dehydroepiandrosterone (DHEA) supplement on age-associated chronic diseases such as cancer, cardiovascular disease, insulin resistance and diabetes, have been reported. However, its mechanism of action in hepatocellular carcinoma in vivo has not been investigated in detail. We have previously shown that during hepatocellular carcinogenesis, DHEA treatment decreases formation of preneoplastic glutathione S-transferase placental form-positive foci in the liver and has antioxidant effects. Here we aimed to determine the mechanism of actions of DHEA, in comparison to vitamin E, in a chemically-induced hepatocellular carcinoma model in rats. Sprague-Dawley rats were administered with control diet without a carcinogen, diets with 1.5% vitamin E, 0.5% DHEA and both of the compounds with a carcinogen for 6 weeks. The doses were previously reported to have anti-cancer effects in animals without known toxicities. With DHEA treatment, cytosolic malate dehydrogenase activities were significantly increased by ${\sim}5$ fold and glucose 6-phosphate dehydrogenase activities were decreased by ${\sim}25%$ compared to carcinogen treated group. Activities of Se-glutathione peroxidase in the cytotol was decreased siguificantly with DHEA treatment, confirming its antioxidative effect. However, liver microsomal cytochrome P-450 content and NADPH-dependent cytochrome P-450 reductase activities were not altered with DHEA treatment. Vitamin E treatment decreased cytosolic Se-glutathione peroxidase activities in accordance with our previous reports. However, vitamin E did not alter glucose 6-phosphate dehydrogenase or malate dehydrogenase activities. Our results suggest that DHEA may have decreased tumor nodule formation and reduced lipid peroxidation as previously reported, possibly by increasing the production of NADPH, a reducing equivalent for NADPH-dependent antioxidant enzymes. DHEA treatment tended to reduce glucose 6-phosphate dehydrogenase activities, which may have resulted in limited supply for de novo synthesis of DNA via inhibiting the hexose monophophaste pathway. Although both DHEA and vitamin E effectively reduced preneoplastic foci in this model, they seemed to fimction in different mechanisms. In conclusion, DHEA may be used to reduce hepatocellular carcinoma growth by targeting NADPH synthesis, cell proliferation and anti-oxidant enzyme activities during tumor growth.

• Nutritional Sciences
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• 제3권1호
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• pp.11-17
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• 2000

This study was intended to examine whether dehydroepiandrosterone (DHEA) and dietary fat level or source could modulate glutathione utilizing detoxifying system activity and the cytosolic NADPH generation in rat liver. Male Sprague-Dawley rats were fed semipurifed diet containing either 2%(w/w) corn oil (low level of corn oil diet: 5 ca% of fat) 15% corn oil (high level of corn oil diet: 31 cal% of fat) or 13% sardine oil plus 2% corn oil(high level of fish oil diet: 31 cal% of fat) for 9 weeks. Half of the rats in each diet group were fed a diet supplemented with 0.2% DHEA (w/w). DHEA administration increased plasma total cholesterol level in low corn oil diet-fed rats. The high fish oil diet significantly decreased plasma total cholesterol level compared to the high corn oil diet. Plasma triglyceride level was not significantly changed by DHEA administration and dietary fat level and source. Fasting plasma glucose level was increased by DHEA administration and fish oil diet. Glucose 6-phosphate dehydrogenase activity in liver tissue was significantly increased by DHEA administration and high fat diet, especially fish oil diet. Malic enzyme activity in liver tissue was significantly increased by DHEA administration and high fat diet, especially fish oil diet. Malic enzyme activity in liver tissue was significantly increased by DHEA administration. DHEA suppressed the glutathione peroxidase, glutathione-dependent enzymes compared to the low corn oil diet, while fish oil diet elevated the activity of glutathione peroxidase and glutathione reductase compared to corn oil diet. These results suggest that DHEA administration and high level of corn oil diet may suppress the cellular detoxifying system activity through reduction of glutathione utilization, while the fish oil diet did not show these effects.