주요 Phytoestrogen들이 제2형 당뇨 마우스의 당질대사에 미치는 효과

This study was conducted to evaluate the antihyperglycemic effects of three phytoestrogens, genistein, coumestrol, and enterolactone, in type 2 diabetic animals. Forty male C57BL/KsOlaHsd-db/db mice were used as a diabetic animal model. The animals were divided into four groups and fed a phytoestrogen-free AIN-76 diet (control), or one of three phytoestrogen-supplemented (3.75 mg/100 g diet) AIN-76 diets for six weeks. During the experimental period, fasting blood glucose levels were measured on week 0, 2, 5, and 6 of the experiment, and oral glucose tolerance tests were performed on the 5th week. After the experimental period, blood concentrations of HbA1c, insulin, and glucagon were measured, and hepatic glycogen content and glucose regulating enzyme activities were analyzed. Fasting blood glucose, HbA1c level, and the area under the blood glucose curve in the oral glucose tolerance test were significantly lower in all of the phytoestrogen-supplemented groups compared to the control group. Plasma glucagon levels were also significantly lower in all of the phytoestrogen-supplemented groups compared to the control group. Hepatic glycogen level was significantly higher in the coumestrol-supplemented group compared to the other groups. However, there were no significant differences in the activities of glucokinase and glucose-6-phosphatase between the groups. These results suggest that all of the three major phytoestrogens tested in the present study were effective in lowering blood glucose levels in type 2 diabetic animals. However, further studies need to be conducted to elucidate the exact mechanism for the hypoglycemic effects of phytoestrogens. 본 실험은 주요 phytoestrogen에 속하는 genistein, coumestrol, enterolactone의 식이보충이 제2형 당뇨동물모델에서 당질대사 개선에 미치는 효과를 알아보고자 C57BL/KsOlaHsd-db/db 마우스를 이용하여 내당능, 당화헤모글로빈 농도, 당대사 관련 효소활성, 조직 중 글리코겐과 최종당화산물 수준 등을 측정하였다. 그 결과, phytoestrogen의 보충(3.75 mg/100 g diet)이 당뇨동물의 체중변화, 식이 및 수분 섭취량 그리고 장기무게에는 유의적인 영향을 미치지 않았으나, 모든 phytoestrogen의 보충은 당뇨동물의 공복 혈당, 경구 내당능 검사 시 혈당반응곡선 아래면적 및 혈중 HbA1c 수준을 유의적으로 낮추었다. 또한 모든 phytoestrogen의 보충은 당뇨동물의 혈장 글루카곤 수준을 유의적으로 낮추었으며, coumestrol과 enterolactone의 보충은 간 조직 중 글리코겐 수준을 유의적으로 증가시켰다. 이상의 결과들은 genistein, coumestrol, enterolactone의 3종 phytoestrogen의 식이보충이 제2형 당뇨동물에서 내당능을 개선시킬 수 있음을 시사하였으나 그 기전에 대해서는 향후 추가 연구가 필요하다고 본다.