• 고려인삼학회:학술대회논문집
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• 고려인삼학회 2002년도 학술대회지
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• pp.129-144
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• 2002

We investigated anti-hyperglycemic and anti-obese effects of Panax ginseng berry extract and its major constituent, ginsenoside Re, in obese diabetic C57BL/6J ob/ob mice and their lean littermates. Animals received daily intraperitoneal injections of Panax ginseng berry extract for 12 days. On Day 5, 150 mg/kg extract-treated ob/ob mice had significantly lower fasting blood glucose levels compared to vehicle-treated mice $(156{\pm}9.0\;mg/dl\;vs.\;243{\pm}15.8mg/dl,$ P<0.01). On Day 12, the extract-treated ob/ob mice became normoglycemic $(137{\pm}6.7\;mg/dl)$ and had significantly improved glucose tolerance. The overall glucose excursion during the two-hour intraperitoneal glucose tolerance test (IPGTT), calculated as area under the curve (AUC), decreased by $46\%$ (P<0.01) compared to vehicle-treated ob/ob mice. Glucose levels of lean mice were not significantly affected by the extract. The improvement in blood glucose levels in 150 mg/kg extracttreated ob/ob mice was associated with significant reduction in serum insulin levels of fed and fasting mice. Consistent with an improvement in insulin sensitivity, hyperinsulinemic euglycemic clamp study revealed a more than 2-fold increase in the rate of insulin-stimulated glucose disposal in treated ob/ob mice $(112{\pm}19.1\;vs.\;52{\pm}11.8{\mu}mol/kg/min$ for the vehicle group, P<0.01). In addition, 150 mg/kg extract-treated ob/ob mice, but not the lean mice, lost significant weight (from $51.7{\pm}1.9g\;on\;Day\;0\;to\;45.7{\pm}1.2$ on Day 12, P<0.01 compared to vehicle-treated ob/ob mice), associated with a significant reduction in food intake (P<0.05) and a very significant increase in energy expenditure (P<0.01) and body temperature (P<0.01). A 12-day treatment with 150 mg/kg Panax ginseng berry extract also significantly reduced plasma cholesterol levels in ob/ob mice. Additional studies demonstrated that ginsenoside Re, a major constituent of the ginseng berry, but not from the root, plays a significant role in anti-hyperglycemic action. This anti-diabetic effect of ginsenoside Re was not associated with body weight changes, suggesting that other constituents in the extract have distinct pharmacological mechanisms on energy metabolism. The identification of a significant anti-hyperglycemic activity in ginsenoside Re may provide an opportunity to develop a novel class of anti-diabetic agent.

• Journal of Yeungnam Medical Science
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• 제36권1호
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• pp.26-35
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• 2019

Background: Dysregulation of hepatic glucose production (HGP) contributes to the development of type 2 diabetes mellitus. Telmisartan, an angiotensin II type 1 receptor blocker (ARB), has various ancillary effects in addition to common blood pressure-lowering effects. The effects and mechanism of telmisartan on HGP have not been fully elucidated and, therefore, we investigated these phenomena in hyperglycemic HepG2 cells and high-fat diet (HFD)-fed mice. Methods: Glucose production and glucose uptake were measured in HepG2 cells. Expression levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase ${\alpha}$ ($G6Pase-{\alpha}$), and phosphorylation levels of insulin receptor substrate-1 (IRS-1) and protein kinase C ${\zeta}$ ($PKC{\zeta}$) were assessed by western blot analysis. Animal studies were performed using HFD-fed mice. Results: Telmisartan dose-dependently increased HGP, and PEPCK expression was minimally increased at a $40{\mu}M$ concentration without a change in $G6Pase-{\alpha}$ expression. In contrast, telmisartan increased phosphorylation of IRS-1 at Ser302 ($p-IRS-1-Ser^{302}$) and decreased $p-IRS-1-Tyr^{632}$ dose-dependently. Telmisartan dose-dependently increased $p-PKC{\zeta}-Thr^{410}$ which is known to reduce insulin action by inducing IRS-1 serine phosphorylation. Ectopic expression of dominant-negative $PKC{\zeta}$ significantly attenuated telmisartan-induced HGP and $p-IRS-1-Ser^{302}$ and -inhibited $p-IRS-1-Tyr^{632}$. Among ARBs, including losartan and fimasartan, only telmisartan changed IRS-1 phosphorylation and pretreatment with GW9662, a specific and irreversible peroxisome proliferator-activated receptor ${\gamma}$ ($PPAR{\gamma}$) antagonist, did not alter this effect. Finally, in the livers from HFD-fed mice, telmisartan increased $p-IRS-1-Ser^{302}$ and decreased $p-IRS-1-Tyr^{632}$, which was accompanied by an increase in $p-PKC{\zeta}-Thr^{410}$. Conclusion: These results suggest that telmisartan increases HGP by inducing $p-PKC{\zeta}-Thr^{410}$ that increases $p-IRS-1-Ser^{302}$ and decreases $p-IRS-1-Tyr^{632}$ in a $PPAR{\gamma}$-independent manner

• 혜화의학회지
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• 제21권1호
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• pp.11-21
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• 2012

New onset diabetes is a major complication after kidney transplantation. However, the natural course of posttransplantation diabetes mellitus (PTDM) remains unclear. The aim of this study was to demonstrate the detailed natural courses of PTDM according to the onset and persistency of hyperglycemia, and to investigate risk factors for development of different courses of PTDM in renal allograft recipients. The purpose of this study is to develop novel immune suppressants for PTDM using of action mechanism of them. The use of immunosuppressive drugs in transplanted patients is associated with the development of diabetes, possibly due to ${\beta}$-cell toxicity. To better understand the mechanisms leading to post-transplant diabetes, we investigated the actions of prolonged exposure of ${\beta}$-cells to therapeutical levels of tacrolimus (FK506) or cyclosporin A(CsA). The immunosuppressive drug cyclosporine(CsA) is a potent agent widely used after organ transplantations and various autoimmune disorders. After using CsA, some patients suffer severe complications including renal and vascular toxicity. The renal or vascular toxicity is influenced by the degree of the endothelial damage. FK506(tacrolimus) is a widely used immunosuppressive agent in the treatment of various medical conditions, including autoimmune disease, bone marrow and organ transplantations. We found some interesting clusters and confirmed the feasibility of cDNA microarray in the study of Immunosuppressant. In this study, we investigated gene expression patterns induced by Immunosuppressant in RIN-m5F of rat insulinoma cell line. Gene expressions evaluated using cDNA microarry in two clusters were increased or decreased. this study provides comprehensive comparison of the patterns of gene expression changes induced by CsA and FK506 in ${\beta}$-cells. This study could establish that the mode of action mechanism by which currently used insulin inhibitors inducing PTDM could be elucidated at least in part, which raises the possibility that novel immune suppressive PTDM can be developed. The molecular biological study on PTDM will also contribute the progress in diabetes research field as well as in that of PTDM.

• 한국식품영양학회지
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• 제22권2호
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• pp.159-165
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• 2009

E. japonica is a well-known medicinal plant in Japan. The leaves of E. japonica were reported to have a hypoglycemic action. However, seeds of E. japonica are discarded and not used. To elucidate for anti-diabetic effects of E. japonica, Type 2 diabetic mice were allocated to control group, E. japonica leaf, and seed extract group. Animals were fed a 2018S Teklad global 18% protein rodent diet. Animals were received daily oral injections of E. japonica leaf or seed extract at a dose of 200 mg/kg body weight for 6 weeks. Body weight, food intake and water intake, and total adipose tissue weight of animals were significantly reduced by feeding of E. japonica leaf extract. All E. japonica extract groups significantly decreased fasting blood glucose, glycosylated hemoglobin levels, size of adipocytes and serum adiponectins. However, they did not have a beneficial effect on the serum triglyceride and cholesterol in the diabetic animals. These results suggest that E. japonica seed and leaf extracts have a antidiabetic effect by controlling of blood glucose and decrease of size of adipocytes in db/db mice and seed extract is more effective in hypoglycemic action than leaf extract.

• 동의생리병리학회지
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• 제24권4호
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• pp.646-652
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• 2010

Gambejaeseup-tang (GBJST) have recently been used as an anti-obesity herbal medicine but their effect and mechanism of action have not been studied. We modified ingredients of GBJST based on the previous experiments about exploring herbs to suppress triglyceride accumulation in 3T3-L1 adipocytes. We investigated the effects of modified GBJST on energy, glucose and lipid homeostasis using female rats with diet-induced obesity and their action mechanism was also determined. Rats fed a high-fat diet (HFD) were divided into 3 groups: rats in each group received 0.2 or 2 g water extracts of modified GBJST (L-GBJST or H-GBJST) or 2 g cellulose per kg body weight (a negative control) on a daily basis. A further group was fed a low-fat diet (LFD) as a positive control. We found that modified GBJST dose-dependently decreased body weight and mesenteric and retroperitoneal fat more than the control. This decrease was due to the reduction in energy intake and the increase of energy expenditure. HFD increased fat oxidation more than LFD and modified GBJST further increased fat oxidation as a major energy source more than the control in a dose-dependent manner. In addition, H-GBJST improved glucose tolerance without changing serum insulin levels during an oral glucose tolerance test. H-GBJST also suppressed the increase of serum total and LDL cholesterol and triglyceride levels by HFD. In conclusion, modified GBJST have a good anti-obesity effect by decreasing energy intake and increasing energy expenditure mainly as fat in female rats with diet-induced obesity. It also improves glucose tolerance and lipid metabolism.

• Archives of Pharmacal Research
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• 제26권12호
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• pp.1047-1054
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• 2003

Molecular chaperones have a crucial role in the folding of nascent polypeptides in endoplasmic reticulum. Some of them are known to be sensitive to the modification by electrophilic metabolites of organic pro-toxicants. In order to identify chaperone proteins sensitive to alkyators, ER extract was subjected to alkylation by 4-acetamido-4 -maleimidyl-stilbene-2,2 -disulfonate (AMS), and subsequent SDS-PAGE analyses. Protein spots, with molecular mass of 160, 100, 57 and 36 kDa, were found to be sensitive to AMS alkylation, and one abundant chaperon protein was identified to be protein disulfide isomerase (PDI) in comparison with the purified PDI. To see the reactivity of PDI with cysteine alkylators, the reduced form ($PDI_{red}$) of PDI was incubated with various alkylators containing Michael acceptor structure for 30 min at $38^{\circ}C$ at pH 6.3, and the remaining activity was determined by the insulin reduction assay. Iodoacetamide or N-ethylmaleimide at 0.1 mM remarkably inactivated $PDI_{red}$ with N-ethylmaleimide being more potent than iodoacetamide. A partial inactivation of $PDI_{oxid}$ was expressed by iodoacetamide, but not N-ethylmaleimide (NEM) at pH 6.3. Of Michael acceptor compounds tested, 1,4-benzoquinone ($IC_{50}, 15 \mu$ M) was the most potent, followed by 4-hydroxy-2-nonenal and 1,4-naphthoquinone. In contrast, 1,2-naphthoquinone, devoid of a remarkable inactivation action, was effective to cause the oxidative conversion of $PDI_{red}$ to $PDI_{oxid}$. Thus, the action of Michael acceptor compounds differed greatly depending on their structure. Based on these, it is proposed that POI, one of chaperone proteins in ER, could be susceptible to endogenous or xenobiotic Michael acceptor compounds in vivo system.

• Journal of Food and Nutrition Research
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• 제9권3호
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• pp.163-169
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• 2021

Decreased adipocyte fatty acid oxidation (FAO) and impaired preadipocyte differentiation characterize hypertrophic expansion of adipose tissue (AT) from obese and insulin resistant humans and are recognized as potential mechanisms for obesity-mediated dyslipidemia. Supplementation of formononetin (FMN), one of the principal isoflavones extracted from red clover or Huangqi (Astragalus roots), has been shown to have beneficial effects on obesity-related hyperlipidemia, a well-established cardiovascular risk factor. However, a target tissue and underlying mechanism(s) through which FMN acts have been under-investigated. Thus, we investigated whether FMN promotes adipocyte FAO and preadipocyte differentiation using 3T3-L1 preadipocytes to provide potential mechanisms of FMN action. We further extended this to the culture of 10T1/2 mesenchymal stem cells (MSCs) as well as mouse AT explants to reflect in vivo effects of FMN. In fully differentiated 3T3-L1 adipocytes, FMN-treatment significantly increased the expression levels of FAO-related proteins such as pAMPK, pACC, and CPT1, all of which were consistently upregulated in AT explant cultures treated with 10 μM FMN. In addition, FMN significantly enhanced the degree of differentiation of both 3T3-L1 preadipocytes and 10T1/2 MSCs into adipocytes as evidenced by Oil Red O staining of cellular lipids. This observation correlated with increased expression levels of key adipogenic transcription factors (PPARγ and C/EBPα) and their down-stream target proteins (FABP4, Glut4 and adiponectin). Moreover, FMN failed to exert its stimulatory effects on preadipocyte differentiation in both cell types in the presence of a PPARγ antagonist, suggesting a PPARγ-dependent effect of FMN. Collectively, these data provide possible mechanisms of action of FMN on lipid metabolism and further support the favorable in vivo effects of FMN in diet and obesity-induced dyslipidemia.

• 한국영양학회:학술대회논문집
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• 한국영양학회 1995년도 추계학술대회 초록
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• pp.11-34
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• 1995

Growth hormone (GH) plays a key role in regulating postnatal growth and can stimulate growth of animals by acting directly on specific receptors on the plasma membrane of tissues or indirectly through stimulating insulin-like growth factor (IGF)-I synthesis and secretion by the liver and other tissues. IGF-I and IGF-Ⅱ are polypeptides with structural similarity with proinsulin that stimulate cell proliferation by endocrine, paracrine and autocrine mechanisms. The initial event in the metabolic action of IGFs on target cells appears to be their binding to specific receptors on the plasma membrane. Current evidence indicates that the mitogenic actions of both IGFs are mediated primarily by binding to the type I IGF receptors, and that IGF action is also mediated by interactions with IGF-binding proteins (IGFBPs). Six distinct IGFBPs have been identified that are characterized by cell-specific interaction, transcriptional and post-translational regulation by many different effectors, and the ability to either potentiate or inhibit IGF actions. Nutritional deficiencies can have their devastating consequence during growth. Although IGF-I is the major mediator of GH's action on somatic growth, nutritional status of an organism is a critical regulator of IGF-I and IGFBPs. Various nutrient deficiencies result in decreased serum IGF-I levels and altered IGFBP levels, but the blood levels of GH are generally unchanged or elevated in malnutrition. Effects of protein, energy, vitamin C and D, and zinc on serum IGF and IGFBP levels and tissue mRNA levels were reviewed in the text. Multiple factors are involved in the regulation of intestinal epithelial cell growth and differentiation. Among these factors the nutritional status of individuals is the most important. The intestinal epithelium is an important site for mitogenic action of the IGFs in vivo, with exogenous IGF-I stimulating mucosal hyperplasia. Therefore, the IGF system appears to provide and important mechanism linking nutrition and the proliferation of intestinal epithelial cells. In order to study the detailed mechanisms by which intestinal mucosa is regulated, we have utilized IEC-6 cells, an intestinal epithelial cell line and Caco-2 cells, a human colon adenocarcinoma cell line. Like intestinal crypt cells analyzed in vivo or freshly isolated intestinal epithelial cells, IEC-6 cells and Caco-2 cells possess abundant quatities of both type Ⅰ and type Ⅱ IGF receptors. Exogenous IGFs stimulate, whereas addition of IGFBP-2 inhibits IEC-6 cell proliferation. To investigate whether endogenously secreted IGFBP-2 inhibit proliferation, IEC-6 cells were transfected with a full-length rat IGFBP-2 cDNA anti-sense expression construct. IEC-6 cells transfected with anti-sense IGFBP-2 protein in medium. These cells grew at a rate faster than the control cells indicating that endogenous IGFBP-2 inhibits proliferation of IEC-6 cells, probably by sequestering IGFs. IEC-6 cells express many characteristics of enterocyte, but do not undergo differentiation. On the other hand, Caco-2 cells undergo a spontaneous enterocyte differentiation. On the other hand, Caco-2 cells undergo a spontaneous enterocyte differentiation after reaching confluency. We have demonstrated that Caco-2 cells produce IGF-Ⅱ, IGFBP-2, IGFBP-3, and an as yet unidentified 31,000 Mr IGFBP, and that both mRNA and peptide secretion of IGFBP-2 and IGFBP-3 increased, but IGFBP-4 mRNA and protein secretion decreased after the cells reached confluency. These changes occurred in parallel to and were coincident with differentiation of the cells, as measured by expression of sucrase-isomaltase. In addition, Caco-2 cell clones forced to overexpress IGFBP-4 by transfection with a rat IGFBP-4 cDNA construct exhibited a significantly slower growth rate under serum-free conditions and had increased expression of sucrase-isomaltase compared with vector control cells. These results indicate that IGFBP-4 inhibits proliferation and stimulates differentiation of Caco-2 cells, probably by inhibiting the mitogenic actions of IGFs.

• Tuberculosis and Respiratory Diseases
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• 제47권5호
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• pp.618-628
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• 1999

연구배경: 세포성장은 세포증식과 세포죽음의 균형에 의해 이루어 진다. 세포성장에 관여하는 여러 growth factor증 IGF-I은 IGF-IR와 결합하여 세포증식을 유발하는 mitogen으로 알려져 있다. 또한 IGF-I에 결합하는 IGFBPs중에 IGFBP-3는 혈액내에 가장 많은 carrier protein으로, IGF-I과 결합하여 IGF-I의 세포증식 효과를 증가 혹은 억제시킨다. 방 법: 3T3 fibroblast 세포를 이용하여 IGF-I과 IGF-IR transcripts를 northern blot으로 확인하고, IGF-I에 의한 mitogenic effect를 MTT assay 및 $^3H$-thymidine incorporation test로 관찰하고, IGF-I의 receptor인 IGF-IR의 활성화를 보기 위해 intracellular $\beta$-subunit의 tyrosine kinase domain의 phosphorylation을 western blot으로 관찰하였다. 또한 IGFBP-3가 3T3 세포에서 mitogenic effect에 미치는 영향을 보기 위해 anti-IGFBP-3와 ${\alpha}IR_3$을 단독 및 병용투여하여 관찰하였다. 결 과: 3T3 세포는 IGF-I와 IGF-IR의 mRNA expression을 보였으며, IGF-I을 투여시 IGF-IR의 intracelluar cytoplasmic protein인 $\beta$-subunit의 tyrosine kinase domain을 phosphorylation시켜 활성화시키며, 5%, 1% serum-containing media에서 세포증식을 보였으나, serum-free media에서는 세포증식을 보이지 않았다. 또한 anti-IGFBP-3 투여와 ${\alpha}IR_3$과 anti-IGFBP-3를 병용투여시는 세포종식이 각각 2배이상 증가하였으나, ${\alpha}IR_3$을 4시간 전처치후 ${\alpha}IR_3$과 anti-IGFBP-3를 병용투여시는 anti-IGFBP-3에 의한 세포종식이 보이지 않은 것으로 보아 IGF -I/IGFBP-3 결합에서 분리되는 free IGF-I어l 의해 세포증식이 유도된 것으로 생각된다. 결 론: IGF-I은 IGF-IR를 phosphorylation시켜 mitogenic effect를 보이며, IGFBP-3는 IGF-I의 mitogenic effect를 억제하는 것으로 생각된다.

• 한국식품영양과학회지
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• 제35권3호
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• pp.321-327
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• 2006

본 연구는 솔잎을 수증기 증류법으로 생산한 솔잎 추출용액을 2형 당뇨 마우스인 db/db mice에게 투여하여 솔잎 추출용액의 혈당강하 효과를 조사하고자 하였다. 이를 위해서 $30{\sim}40g$정도의 6주령 수컷 C57BL/Ksj(BL/Ls) homozygous diabetic(db/db) mice(SPF)를 음성대조군(corn oil), 솔잎 추출용액 저용량군(112.5 mg/kg), 고용량군(450 mg/kg) 및 양성대조군(metformin 150 mg/kg)의 4군으로 나누어 6주간 시험물질을 경구 투여하였다. 6주 사육기간 동안 혈당의 변화를 측정하기 위해 매주 1회씩 6시간 공복 시 미정맥으로부터 혈당을 측정하였으며, 6주 실험종료 후 모든 동물은 희생시킨 후 복대정맥에서 혈액을 채취하여 당화혈색소(HbAlc), 혈청 인슐린, C-peptide 및 leptin 농도 등을 측정하였다. 그 결과 다음과 같은 결론을 얻었다. 식이섭취량은 솔잎 추출용액 투여군에서 감소하는 경향을 보였으며, 양성대조군은 섭취량의 변화가 없었고, 1일 1마리당 평균섭취량은 고용량군이 음성대조군 및 양성대조군에 비하여 유의적으로 낮은 섭취량을 보였다. 체중은 군 간의 차이가 나타나지 않았으며, 간 무게와 상대적 간 무게는 음성대조군에 비하여 솔잎 추출용액 고용량군에서 유의적으로 높게 나타났다. 혈당은 솔잎 추출용액 고용량군에서 실험개시 3주부터 음성대조군에 비하여 유의적으로 감소하였으며, 최종 혈당은 저용량과 고용량군 모두 음성 대조군에 비해 유의적으로 낮아졌고, 용량 의존적인 경향성을 나타내었다. 당화혈색소의 함량 역시 솔잎 추출용액 고용량군에서 음성대조군에 비해 유의적이지는 않지만 낮은 경향을 보였다. 혈청 인슐린과 C-peptide농도는 솔잎 추출용액의 투여에 따른 차이가 나타나지 않아 솔잎 추출용액이 인슐린의 생성에 영향을 미치지는 않는 것으로 사료된다. 혈청 leptin 농도는 유의적이지는 않지만 음성대조군에 비해 솔잎 추출용액 투여군에서 높은 경향을 나타냈으며, 혈당과 음의 상관관계를 나타내고 있어 솔잎 추출용액의 혈당강하 효과의 작용기전으로 leptin과 관련된 인슐린 감수성에 영향을 미첬을 가능성이 있는 것으로 기대된다. 그러므로 본 연구에 사용한 112.5 mg/kg 및 450 mg/kg의 솔잎 추출용액은 6주 경구투여 시 혈당강하 효과를 나타냈으며, 인슐린의 농도에는 영향을 미치지는 않았다. 이러한 결과는 솔잎 추출용액의 혈당강하 효과의 작용기전이 인슐린의 감수성이나 저항성에 영향을 미쳤을 가능성이 있는 것으로 기대되며, 본 연구가 앞으로 솔잎 추출용액에 대한 다양한 연구를 활성화하는데 기여할 것으로 사료된다.