• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.117-123
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• 1992

The present study was undertaken in order to elucidate the effects of pretreatment with nicotinamide on changes in serum glucose level, body weight, water consumption, serum insulin concentration, and the activity of pancreatic enzyme in rats treated with streptozotocin (STZ). Histological studies were also carried out to evaluate the effects on pancreatic tissues and Langerhans's islet cells. Nicotinamide pretreatment in STZ diabetic rats inhibited the rise of fasting serum glucose concentration and water consumption. Pretreatment with nicotinamide significantly increased the concentration of serum insulin and body weight changes compared to the STZ-treated group. Pancreatic lipase and trypsin activities were increased, but amylase activity was decreased and pancreatic $\beta$ -cell was destroyed by STZ. Pvetreatment with nicotinamide prevented these STZ-induced changes. These results suggest that nicotinamide pretreatment supresses STZ-induced changes in pancreatic enzymes by preventing $\beta$-cell destruction and therefore maintaining a normal serum insulin revel.

• The korean journal of orthodontics
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• v.53 no.6
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• pp.393-401
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• 2023

Objective: To investigate the long-term effects of 4-hexylresorcinol (4HR) on facial skeletal growth in growing male rats, with a focus on diabetic animal models. Methods: Forty male rats were used. Of them, type 1 diabetes mellitus was induced in 20 animals by administering 40 mg/kg streptozotocin (STZ), and they were assigned to either the STZ or 4HR-injected group (STZ/4HR group). The remaining 20 healthy rats were divided into control and 4HR groups. We administered 4HR subcutaneously at a weekly dose of 10 mg/kg until the rats were euthanized. At 16 weeks of age, whole blood was collected, and microcomputed tomography of the skull and femur was performed. Results: All craniofacial linear measurements were smaller in the STZ group than in the control group. The mandibular molar width was significantly smaller in the 4HR group than in the control group (P = 0.031) but larger in the STZ/4HR group than in the STZ group (P = 0.011). Among the diabetic animals, the STZ/4HR group exhibited significantly greater cortical bone thickness, bone mineral density, and bone volume than the STZ group. Serum testosterone levels were also significantly higher in the STZ/4HR group than in the STZ group. Conclusions: 4HR administration may have divergent effects on mandibular growth and bone mass in healthy and diabetic rats. In the context of diabetes, 4HR appears to have beneficial effects, potentially through the modulation of mitochondrial respiration.

• Journal of Nutrition and Health
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• v.47 no.6
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• pp.394-402
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• 2014

Purpose: Dendropanax morifera Leveille (DML) exhibits diverse biological and pharmacological activities, including anti-oxidative effect, anti-cancer activity, hepatoprotection, immunological stimulation, and bone regeneration. As part of the identification for novel functions of DML, we investigated the therapeutic effects of DML on diabetes induced by streptozotocine (STZ) treatment. Methods: First, the four extracts including the water extract of leaf (DLW), the ethanol extract of leaf (DLE), the water extract of stem (DSW), and the ethanol extract of stem (DSE) were collected from the leaf and stem of DML using a hot water and ethanol solvent. Alterations in body weight, glucose concentration, insulin level, and pancreatic islet structure were investigated in diabetic mice after treatment with extracts of DML for 2 weeks. Results: Among four extracts, the highest level of total polyphenols and total flavonoids was detected in DLW, while the lowest level of these was measured in DSE. The radical scavenging activity was also higher in DLW than in the other three extracts at the concentration of $25-100{\mu}g/mL$, although this activity was maintained at a constant level in all groups at the concentration of $500{\mu}g/mL$. Based on the results of anti-oxidant activity, DLW and DLE were selected for examination of anti-diabetic effects in a diabetes model. Body weight was gradually decreased in all STZ treated groups compared with the No treated group. However, four STZ/DML treated groups maintained a high level of body weight during 7-14 days, while the STZ/vehicle treated group showed a gradual decrease of body weight during the same period. Also, a significant decrease or increase in the concentration of glucose and insulin in the blood of the diabetes model was detected in a subset of groups, although the highest increase was detected in the STZ/DLE-200 treated group. In addition, the histological structure of pancreatic islet was significantly recovered after treatment with DLW and DLE. Conclusion: These results suggest that DLW and DLE may contribute to attenuation of clinical symptoms of diabetes as well as prevent the destruction of pancreatic ${\beta}$-cells in STZ-induced diabetes mice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.3
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• pp.203-208
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• 1991

The present study was undertaken in order to elucidate the effects of pretreatment with nicotinamide on changes in the hepatic metabolizing enzyme system inducted by streptozotocin (STZ). In rats, STZ(50mg/kg) administered by tail vein caused a significant rise in hepatic aniline hydroxylase and a decrease in aminopyrine N-demethylase when compared to control (p<0.05). Pretreatment with nicotinamice inhibited these effects (p<0.05). Similarly, STZ induced changes in hepatic microsomal cytochrome P-450 activity were inhibited by pretreatment with nicotinamide (p<0.05). However, changes in UDP-glucuronyl transferase and sulfortransferase activity were not significantly different(p>0.05). Pretreatment with nicotinamide also prevented STZ induced increases in glutathion S-tranferase activity when compared to the control(p<0.05). There results suggest that nicotinamide pretreatment suppresses STZ-induced changes in the hepatic metabolizing enzyme system.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.818-824
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• 2011

Eight LW${\times}$D crossbred, castrated weanling piglets were used to examine the effect of hyperglycemia by streptozotocin (STZ)-injection on oxidative and anti-oxidative status in circulating fluid. Every two of the eight piglets were intravenously administrated STZ at a dose of 0 (control), 100, 125 or 150 mg/kg BW, respectively, and on 15th day after the STZ-injection, some markers of the oxidative stress in circulating fluid were measured to evaluate oxidative and anti-oxidative status in the piglets. First, piglets with hyperglycemia were selected from the STZ-injected piglets as measured by the levels of fasting plasma glucose (FPG) during 2 weeks after the STZ-injection. Additionally, data obtained from the intravenous glucose tolerance test (IVGTT) on 14th day were analyzed. Secondly, the data obtained in this experiment were divided into the control group and the hyperglycemic (STZ) group, and compared. The FPG level or area under curve (AUC) for plasma glucose during the IVGTT in the STZ-induced diabetic piglets was slightly significantly (FPG, p = 0.070; AUC, p = 0.072) higher compared with the control. On the other hand, the plasma level of lipid peroxidation in the STZ-induced diabetic piglets was significantly (p<0.05) higher compared with the control. These results raise the possibility that STZ-induced diabetic piglets produced in this study can be used as a diabetic animal model to research the pathogenic mechanisms or therapy of complications in diabetic mellitus.

• Nutritional Sciences
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• v.6 no.4
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• pp.201-208
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• 2003

This research was conducted to study the effects of the supplementation of multi-extracts of mori folium (MF) and of exercise on plasma insulin and glucose levels in streptozotocin (STZ)-induced diabetic rats. Eight male Sprague-Dawley rats, 4 weeks old, were assigned to each experimental group and were raised in the laboratory for 10 weeks. The animal groups consisted of a normal-control group, a STZ-control group, 3 STZ-induced diabetic groups supplemented ad libitum with various amounts of MF extracts (MF-720, MF-360, and MF-180 groups), and a STZ-induced diabetic group supplemented with MF-360 along with exercise. In the normal-control group, glucose tolerance tests resulted in the peak blood glucose level being achieved in 15 minutes and a fasting blood glucose level being achieved in 60 minutes. In the STZ-control group, the peak blood glucose level was reached after 60 minutes and, even after 90 minutes, blood glucose shown at a significantly higher level compared to the fasting levels. In the groups supplemented with MF extracts, the blood glucose level peaked after 30 minutes of glucose challenge, and returned to the fasting level after 90 minutes; the MF-360 and MF-360+exercise groups showed the best levels of glucose tolerance. Blood glucose levels in the STZ-induced diabetic groups were significantly higher compared to the normal-control group. However, after 7 weeks of supplementation with MF extracts, a significant lowering of blood glucose levels was observed in all groups supplemented with the MF extract. The best effect was observed in the group given MF extract combined with exercise. Compared to the normal-control group, blood insulin levels were significantly lower in all STZ-induced diabetic groups; however, a significantly higher level of insulin was observed in the groups given MF extracts compared to the STZ-control group. This study shows that the supplementation of MF extracts in STZ-induced diabetic rats resulted in increased blood insulin levels and lower blood glucose levels.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.375-382
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• 1999

Growing evidence indicates that enhanced generation or actions of nitric oxide (NO) are implicated in the pathogenesis of hypertension in spontaneously hypertensive rats and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. We investigated whether inducible nitric oxide synthase (iNOS) expression in STZ-induced diabetic rats is responsible for the alterations of vascular reactivity. Diabetic state was confirmed 28 days after injection of STZ (i.p) in rats by measuring blood glucose. In order to evaluate whether short term (4 weeks) diabetic state is related with altered vascular reactivity caused by iNOS expression, isometric tension experiments were performed. In addition, plasma nitrite/nitrate (NOx) levels and expression of iNOS in the lung and aorta of control and STZ-treated rats were compared by using Griess reagent and Western analysis, respectively. Results indicated that STZ-treated rats increased the maximal contractile response of the aorta to phenylephrine (PE), and high $K^+,$ while the sensitivity remained unaltered. Endothelium-dependent relaxation, but not SNP-mediated relaxation, was reduced in STZ-treated rats. Plasma nitrite/nitrates are significantly increased in STZ-treated rats compared to controls. The malondialdehyde (MDA) contents of liver, serum, and aorta of diabetic rats were also significantly increased. Furthermore, nitrotyrosine, a specific foot print of peroxynitrite, was significantly increased in endothelial cells and smooth muscle layers in STZ-induced diabetic aorta. Taken together, the present findings indicate that enhanced release of NO by iNOS along with increased lipid peroxidation in diabetic conditions may be responsible, at least in part, for the augmented contractility, possibly through the modification of endothelial integrity or ecNOS activity of endothelium in STZ-diabetic rat aorta.

• Journal of Life Science
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• v.20 no.5
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• pp.691-696
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• 2010

In this study, we investigated the antioxidative effects of So-Dang-Tang (SDT) on streptozotocin (STZ)-induced diabetic rats. Diabetes was induced by intraperitoneal injection of STZ (45 mg/kg body weight) into Sprague-Dawley rats. The SDT (200 mg/kg) and the reference drug, glibenclimide (1mg/kg), were orally administered once a day for 28 days in STZ-induced diabetic rats. The activity of antioxidant enzymes, including those of superoxide dismutase (SOD) and catalase, and the levels of glutathione (GSH) and production of malondialdehyde (MDA) were measured in the liver, kidney, and pancreas of diabetic rats. Treatment with SDT in STZ-induced diabetic rats significantly increased the activities of antioxidant enzymes and GSH levels in the liver, kidney, and pancreas when compared to those of the STZ-control group. SDT also significantly decreased lipid peroxidation product and MDA levels in STZ-induced diabetic rats. These results indicate that SDT has an antioxidative action in STZ-induced diabetic rats.

• Biomolecules & Therapeutics
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• v.5 no.3
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• pp.253-259
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• 1997

The effect of corticosteroid on the diabetic pregnant rats and their fetuses was investigated. Streptozotocin (STB) was injected into the pregnant rats on the fifth day of pregnancy. Dexamethasone (DXM) was injected into the pregnant rats on the 17th, 18th, 19th and 20th days of pregnancy In prenatal rats, the body weight, an abortion rate, number of fetus, the ratio of lecithin/sphingomyelin (L/S) and the levels of blood glucose and phosphatidylglycerol (PG) were determined. In the postnatal rats, the body weight, the levels of blood glucose, fetal number, stillbirth rate, an organ weight and the levels of hepatic glycogen, protein and triglyceride were determined. The body weight of fetuses was lower in the DXM group and higher in the STZ group than the those of control group. Blood glucose of fetuses produced hypoglycemia in the STZ group compared with the control group. A significant increase in the abortion and stillbirth rates was observed in STZ group. The levels of glycogen, protein and triglyceride in fetus liver and the weight of pancreas were significantly increased in the 572 and STZ+DXM groups compared with the control group. The L/S ratio and the level of PG in the amniotic (quid were significantly decreased in STZ group compared with the control group, whereas those of the STZ+DXM group were similar to the control group. It has been observed that corticosteroid administration on the STZ-induced diabetic rats during final stage of pregnancy can prevent the respiratory depression syndrome of neonatal rats.

• Journal of Nutrition and Health
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• v.36 no.10
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• pp.981-989
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• 2003

The hypoglycemic effects of four edible plants (Angelicae tenuissimae (A. ten.), Pleurospermum kamtschaticum (P. kam.), Adenophora remotiflora (A. rem.) and Zanthoxylum schinifolium (Z. sch.)) in streptozotocin (STZ) -induced diabetic rats were investigated. Sprague-Dawley male rats weighing 190-230 g were induced diabetes mellitus by the STZ injection (45 mg/kg) into the tail vein and were divided into six groups ; normal, STZ-control and four edible plant groups (A. ten., P kam., A. rem. and Z. sch. groups). Normal and STZ-control groups were fed a AIN-93 diet and four groups of STZ-induced diabetic rats were fed one of each experimental diets containing 10％ of the edible plant powder for 4 weeks. Diabetic rats showed the lower weight gain compared to the normal rats. In experimental groups except P. kam., AST activities were close to normal. A. ten. group were lowered ALT activities slightly. The plasma glucose levels of the diabetic experimental groups were significantly decreased at 4th week. The plasma insulin levels in diabetic experimental groups were not significantly different compared to the STZ-control group. The liver glycogen levels in STZ injected rats were significantly lower in compared to the normal rats. However no significant differences were found in response experimental plants intake in diabetic rats. The muscle glycogen were not significantly different among all the groups.