• Nutrition Research and Practice
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• v.18 no.1
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• pp.46-61
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• 2024

BACKGROUND/OBJECTIVES: An increasing life expectancy in society has burdened healthcare systems substantially because of the rising prevalence of age-related metabolic diseases. This study compared the effects of animal protein hydrolysate (APH) and casein on metabolic diseases using aged mice. MATERIALS/METHODS: Eight-week-old and 50-week-old C57BL/6J mice were used as the non-aged (YC group) and aged controls (NC group), respectively. The aged mice were divided randomly into 3 groups (NC, low-APH [LP], and high-APH [HP] and fed each experimental diet for 12 weeks. In the LP and HP groups, casein in the AIN-93G diet was substituted with 16 kcal% and 24 kcal% APH, respectively. The mice were sacrificed when they were 63-week-old, and plasma and hepatic lipid, white adipose tissue weight, hepatic glucose, lipid, and antioxidant enzyme activities, immunohistochemistry staining, and mRNA expression related to the glucose metabolism on liver and muscle were analyzed. RESULTS: Supplementation of APH in aging mice resulted in a significant decrease in visceral fat (epididymal, perirenal, retroperitoneal, and mesenteric fat) compared to the negative control (NC) group. The intraperitoneal glucose tolerance test and area under the curve analysis revealed insulin resistance in the NC group, which was alleviated by APH supplementation. APH supplementation reduced hepatic gluconeogenesis and increased glucose utilization in the liver and muscle. Furthermore, APH supplementation improved hepatic steatosis by reducing the hepatic fatty acid and phosphatidate phosphatase activity while increasing the hepatic carnitine palmitoyltransferase activity. Furthermore, in the APH supplementation groups, the red blood cell (RBC) thiobarbituric acid reactive substances and hepatic H₂O₂ levels decreased, and the RBC glutathione, hepatic catalase, and glutathione peroxidase activities increased. CONCLUSIONS: APH supplementation reduced visceral fat accumulation and alleviated obesity-related metabolic diseases, including insulin resistance and hepatic steatosis, in aged mice. Therefore, high-quality animal protein APH that reduces the molecular weight and enhances the protein digestibility-corrected amino acid score has potential as a dietary supplement for healthy aging.

• Journal of Periodontal and Implant Science
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• v.2 no.1
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• pp.7.2-7.2
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• 1972

• Proceedings of the Korean Society of Applied Pharmacology
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• 2002.07a
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• pp.229-229
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• 2002

• Journal of Nutrition and Health
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• v.25 no.7
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• pp.617-627
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• 1992

This study was attempted to observe the possibility of body fat distribution and fasting serum insulin as potential predictive factors for obesity and energy intake. Subjects participated in this study were seventeen pairs of upper body type women and lower body type women whose age weight BMI daily energy expenditure per body weight were equally matched, Waist to hip girth ratio(WHR) was measured as a criteria of body fat distribution. Comparison of eating behavior between upper body type and lower body type women did not show any significant differences in meal size meal duration and energy intake per minute While serum free fatty acid level was lower in upper body type women percentage of body fat and fasting serum insulin triglycerde level of upper body type women were statistically higher than those of lower body type women(p<0.05) Our data may indicate the possibility that sympathetic nervous system activity was suppressed in upper body type women which needs ti be examined in future studies. In addition since the upper body type women were dieting over the period of survey with the intention of weigh loss we can conclude that upper body type women had larger variabilities than lower body type women in terms of daily energy intake level.

• Molecules and Cells
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• v.43 no.4
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• pp.373-383
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• 2020

Our previous study revealed a novel role of Fas-associated death domain-containing protein (FADD) in islet development and insulin secretion. Insulin-degrading enzyme (IDE) is a zinc metalloprotease that selectively degrades biologically important substrates associated with type 2 diabetes (T2DM). The current study was designed to investigate the effect of FADD phosphorylation on IDE. We found that the mRNA and protein levels of IDE were significantly downregulated in FADD-D mouse livers compared with control mice. Quantitative real-time polymerase chain reaction analysis showed that FADD regulates the expression of IDE at the transcriptional level without affecting the stability of the mRNA in HepG2 cells. Following treatment with cycloheximide, the IDE protein degradation rate was found to be increased in both FADD-D primary hepatocytes and FADD-knockdown HepG2 cells. Additionally, IDE expression levels were reduced in insulin-stimulated primary hepatocytes from FADD-D mice compared to those from control mice. Moreover, FADD phosphorylation promotes nuclear translocation of FoxO1, thus inhibiting the transcriptional activity of the IDE promoter. Together, these findings imply a novel role of FADD in the reduction of protein stability and expression levels of IDE.

• Nutrition Research and Practice
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• v.6 no.5
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• pp.405-413
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• 2012

Rho iso-alpha acids-rich extract (RIAA) from Humulus lupulus (hops) and proanthocyanidins-rich extracts (PAC) from Acacia nilotica exert anti-inflammatory and anti-diabetic activity in vitro and in vivo. We hypothesized that a combination of these two extracts would exert enhanced effects in vitro on inflammatory markers and insulin signaling, and on nonfasting glucose and insulin in db/db mice. Over 49 tested combinations, RIAA:PAC at 5:1 ($6.25{\mu}g/mL$) exhibited the greatest reductions in $TNF{\alpha}$-stimulated lipolysis and IL-6 release in 3T3-L1 adipocytes, comparable to $5{\mu}g/mL$ troglitazone. Pretreatment of 3T3-L1 adipocytes with this combination ($5{\mu}g/mL$) also led to a 3-fold increase in insulin-stimulated glucose uptake that was comparable to $5{\mu}g/mL$ pioglitazone or $901{\mu}g/mL$ aspirin. Finally, db/db mice fed with RIAA:PAC at 5:1 (100 mg/kg) for 7 days resulted in 22% decrease in nonfasting glucose and 19% decrease in insulin that was comparable to 0.5 mg/kg rosiglitazone and better than 100 mg/kg metformin. RIAA:PAC mixture may have the potential to be an alternative when conventional therapy is undesirable or ineffective, and future research exploring its long-term clinical application is warranted.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.3
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• pp.236-244
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• 2021

Objective: Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, irregular menstruation, ovulatory dysfunction, and insulin resistance. Recent studies have reported the possible role of phytoestrogens in PCOS. This animal study aimed to evaluate the effects of genistein on insulin resistance, inflammatory factors, lipid profile, and histopathologic indices on PCOS. Methods: PCOS was induced by 1 mg/kg of letrozole in adult Sprague-Dawley rats. The rats then received normal saline (PCOS group), 150 mg/kg of metformin, or 20 mg/kg of genistein dissolved in 1% methylcellulose solution for 42 days. Body weight, the glycemic and lipid profile, and inflammatory, antioxidative, and histopathological parameters were assessed at the end of the intervention. Results: Treatment with genistein significantly alleviated the increased level of fasting blood insulin (p=0.16) and the homeostatic model assessment of insulin resistance (p=0.012). In addition, the genistein group had significantly lower levels of serum malondialdehyde (p=0.039) and tumor necrosis factor-alpha (p=0.003), and higher superoxide dismutase enzyme activity (p<0.001). Furthermore, the histopathological analysis indicated that genistein administration led to an increase in luteinization and the development of fewer cysts (p<0.05). Conclusion: Biochemical and histopathological analyses indicated that genistein administration to rats with PCOS induced significant remission in oxidative, inflammatory, and glycemic and histopathologic parameters.

• Journal of Life Science
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• v.27 no.3
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• pp.289-294
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• 2017

Diabetes mellitus is associated with insulin resistance, which leads to down-regulation of insulin signaling and the decreased glucose uptake. Adipocytes are sensitive to insulin, and closely implicated in insulin resistance and diabetes. Insulin stimulates differentiation of preadipocytes to adipocytes, and increases glucose transport. Allium species have been used as traditional medicine and health-promoting foods. Allium hookeri (A. hookeri) is reported to improve the pancreatic ${\beta}-cell$ damage and exhibit pancreatic anti-inflammatory activity in streptozotocin-induced diabetic rats. We investigated whether A. hookeri extract (AHE) may stimulate glucose uptake in adipocytes through increasing insulin sensitivity. AHE enhanced fat accumulation, a differentiation biomarker, under the partial induction of differentiation by insulin. $PPAR{\gamma}$, a transcription factor highly expressed in adipocytes, promotes adipocyte differentiation and insulin sensitivity. AHE increased the differentiation of preadipocytes through up-regulation of $PPAR{\gamma}$. The activation of $PPAR{\gamma}$ increases the GLUT4 expression during adipocyte differentiation. GLUT4 is responsible for glucose uptake into the adipocytes. AHE increased the expression of GLUT4 in adipocytes, and subsequently enhanced the insulin-stimulated glucose uptake. These results suggest that AHE promotes adipocyte differentiation through activation of $PPAR{\gamma}$, and leads to enhance glucose uptake in adipocytes along with GLUT4 up-regulation. Thus, AHE may be effective for the insulin-sensitizing and anti-diabetic activities.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.114-120
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• 2006

Anti-diabetic effects of extracts and fractions of Sasa borealis (SB), white lotus roots (LR) and leaves (LL), and their mixture were determined in 3T3-L1 adipocytes and Min6 cells by investigating insulin-sensitizing activity and glucose-stimulated insulin secretion, respectively. SB, LR, LL, and mixture of SB, LR, and LL (3 : 2 : 3) were extracted using 70% ethanol, and m mixture extract was fractionated by XAD-4 column chromatography with serial mixture solvents of methanol and water. Fractional extractions were utilized for anti-diabetic effect assay. SB and LR extracts increased insulin-stimulated glucose uptake, but not as much as mixture of SB, LR, and LL. Significant insulin-sensitizing activities of 20 and 80% methanol fractions of SB, LR, and LL mixture extract were observed in 3T3-L1 adipocytes, giving 0.5 or $5\;{\mu}g/mL$ each fraction with 0.2 nM insulin to attain glucose uptake level similar to that attained by 10 nM insulin alone. Similar to pioglitazone, peroxisome proliferators-activated $receptor-{\gamma}\;(PPAR-{\gamma})$ agonist, 20 and 80% methanol fractions increased adipocytes by stimulating differentiation from fibroblasts and triglyceride synthesis. LL extract and 20, 60, and 80% methanol fractions of the mixture suppressed ${\alpha}-amylase$ activity, but did not modulate insulin secretion capacity of Min6 cells in both low and high glucose media. These data suggest 20 and 80% methanol tractions contain potential insulin sensitizers with functions similar to that of $PPAR-{\gamma}$ agonist. Crude extract of SB, LR, and LL mixture possibly improves glucose utilization by enhancing insulin-stimulated glucose uptake and inhibiting carbohydrate digestion without affecting insulin secretion in vivo.

• 한국인삼전략화협의회:학술대회논문집
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• v.2003 no.09
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• pp.77-88
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• 2003

"Ginseng (Panax ginseng C.A. Meyer) has been a popular herbal remedy used in eastern Asian cultures for thousands of years, and a number of health claims are made for it. Modern therapeutic claims for ginseng refer to vitality, immune function, cancer, cardiovascular diseases, diabetes and sexual function. These claims are mostly based on uncontrolled or non-randomized studies. Among modern therapeutic claims, however, therapeutic effects for diabetes can reasonably be accepted. Following experiment was done recently in our lab: this study was designed to compare the antidiabetic activities between Ginseng Radix Alba (GRA), Ginseng Radix Rubra (GRR) and Panax Quinquefoli Radix (PQR) in multiple low dose (MLD) streptozotocin (STZ) (20mg/kg i.p injection for 5 days) induced diabetic rats. In the glucose tolerance test, 500mg/kg of each ginseng ethanol extract was admoinistered intraperitoneally 30min before glucose challenge. While GRA failed to lower blood glucose level, GRR and PQR both significantly prevented the hyperglycemia when compared with the control group. In the MLD STZ-induced diabetic rats, 300 mg/kg of each ginseng ethanol extract was administered intraperitoneally for 2 weeks. Plasma glucose and insulin levels were markedly improved in all treatment groups. While GRR showed the highest antidiabetic activity, and GRA and PQR revealed somewhat equipotent antidiabetic activities, but less than that in GRR-treated group as for as blood parameters and diabetic symptoms such as polydipsia are concerned. Blood glucose levels were closely associated with plasma insulin levels, and this result may suggest that ginseng ethanol extracts showed the activity to enhance insulin secretion as well as preventing destruction of pancreatic islet cells. To elucidate the relationship between antidiabetic activity and ginsenoside profiles, seven major ginsenoside were quantified by HPLC. We figured out the fact that protopanaxatriol (PPT) : proptopanaxadiol (PPD) ratio might play an important role in its hypoglycemia effects."