운동 시 제 1형 당뇨쥐의 골격근 및 간 조직내 Pro- & Macroglycogen 동원의 차이 = The difference of pro- & macroglycogen depletion in type 1 diabetic rat liver and skeletal muscle during exercise

국문 초록 (Abstract)

조인호. 운동 시 제 1형 당뇨주의 골격근 및 간 조직내 Pro- & macroglycogen 동원의 차이. 운동과학, 제13권 2호, 201-210,2004. 이 연구는 장시간의 운동 시 제 1형 당뇨 쥐의 간과 가자미근 내(총 글리코겐, proglycogen, macroglycogen)의 동원 양상 차이를 규명하였다. 최근의 연구에서 글리코겐은 분자의 크기에 따라 명백하게 두 가지의 형태 즉 proglycogen(PG, ~400kDa, 산에 용해안됨)과 macroglycogen(MG, 10,000kDa 산에 용해 됨)이 존재하며 대사적으로 다르게 조절된다고 보고하고 있다. 그러나 이러한 PG와 MG가 운동 시 당뇨조직에서 어떻게 조절되는 가에 관한 연구는 전무하다.
따라서 이 연구에서는 32마리의 쥐(Sprague Dawley)를 이용하여, 통제군(CON, n=16)과 streptozotocin 투여로 당뇨를 유발시킨 당뇨군(DM, n=16)으로 나누었으며, 각 그룹(통제군, 당뇨군)은 다시 비운동군(REST, n=8)과 운동군(EXE, n=8)으로 세분하였다. 운동군의 쥐는 총 3시간(30분 수영, 5분 휴식× 6회)의 운동을 실시하였으며, 이후 간과 하지근의 가자미근육을 적출하여 분석에 사용하였다.
안정 시 및 운동 후 혈장 글루코스 농도는 당뇨군에서 유의하게 높게 나타났다(p<.05). 안정 시 간의 총 글리코겐 농도는 두 그룹간 차이를 보이지 않았으나 흥미롭게도, 안정시 당뇨군의 근육 내 총 글리코겐과 PG의 농도는 통제군에 비해 높게 나타났다. 운동 후, 통제군에 있어서 간내 글리코겐의 농도는 유의한 감소를 보인데 비해 당뇨군은 그 감소폭이 적어 유의수준에 미치지 못했다. 근육 내 PG의 동원 형태는 두 그룹 모두 총 글리코겐의 형태외 비슷한 양상을 보여, 장시간의 운동 후 두 그룹의 총 글리코겐과 PG농도의 유의한 감소는 보이지 않았다. 이에 비해 안정 시 MG의 농도는 그룹간 큰 차이는 보이지 않았으나 운동 후 당뇨집단에 있어서 MG의 농도는 유의하게 감소하였다(p<.05). 결과적으로 운동 후 당뇨군의 간내 총 글리코겐은 유의한 감소는 보이지 않았다. 근육 내 총 글리코겐과 PG의 변화양상은 각 그룹에 있어서 비슷한 형태를 보였으나 운동 후 MG의 농도는 당뇨군에서만 유의한 감소를 보였다. 따라서 이러한 결과를 토대로 본다면 장시간의 운동에 따라 당뇨조직(간 및 근육)내 글리코겐(총, PG, MG)의 동원에는 대사적으로 차이가 있다는 것을 알 수 있다.

다국어 초록 (Multilingual Abstract)

Cho, I.H. The dfference of pro- & macroglycogen depletion in type Ⅰ diabetic rat liver and skletal muscle during exercise. Exercise Science, 13(2): 201-210, 2004, We investigated the effects of prolonged exercise on glycogen(total, proglycogen and macroglycogen) mobiization in liver and soleus muscle from type Ⅰ diabetic rat. Recently it has been reported that glycogen exists in two distinguish forms, prolycogen, (PG, acid-insolude, ~4oo kDa) and macroglycogen (MG, acid-soluble, ~10,000 KDa), and they are regulated differently during exercise in normal skeletal muscle. However, little is known about the physiological and the metabolic differences between these two forms of glycogen in diabetic muscles. For this study, thirty two rats were used and were divided into two experimental conditions: either control (CON) or streptozotocin-induced diabetic (DM). Animals in each condition were randomly assigned to one of two groups: sacrificed at resting condition without exercise (REST), sacrificed immediately after exercise(EXE). All animals in exercising groups swam for 3hr (30min, 5min rest x 6 bouts), then liver and soleus muscle was dissected out and freezed for further analysis.
Plasma glucose concentration at rest was significantly higher in DM than CON (p<.05). Liver total glycogen contents at rest were not significantly different between both groups, but exercise induced a significantly reduction in CON(p<.05) but not in DM. Interestingly, muscle total and PG content in DM at rest was higher than in CON. The patterns of muscle PG depletion during exercise was mostly same as total glycogen at both groups. Prolonged exercise resulted in no significant decrease in muscle total and PG contents in both groups. MG content at rest was not significantly different between both groups. MG content was significantly decreased in DM immediately after exercise(p<.05).
It was concluded that there was no significant reduction of liver total glycogen in DM after exercise. Muscle total and PG showed similar pattern in both groups respectively, but it was significantly different in MG content between normal and diabetic liver and skeletal muscle during rest and exercise.

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