Myo-Inositol Synthesis in the Milk of Lactating Rats

쥐 우유중의 Myo-Inositol 생성에 관한 연구

A high concentration of myo-Inositol in rat's milk was observed (61-91mg. of myo-Inositol per 100g of milk) by gas-liquid chromatographic method, using a 3% SE-52 column. Feeding experiments showed that approximately 85% of myo-Inositol in milk was from dietary origin: the rest was considered to be synthesized by 1L-myo-Inositol-1-phosphate lyase. Results suggested that the biosynthesis was not sufficiently high to permit the maintenance of its myo-Inositol level in milk. However, study $using(^{14}C)-glucose$ injection into lactating female rats confirmed biosynthesis of myo-Inositol from glucose in mammary gland. This biosynthesis reached a maximum within an hour after $(^{14}C)-glucose$ injection intraperitoneally as lactose biosynthesis did. Study using $(^3H)-myo-Inositol$ confirmed that most of the myo-Inositol in milk was transported from blood plasma myo-Inositol against a concentration gradient. About four hours after the beginning of the injection of $(^{14}C)-glucose$, the specific radioactivity of myo-Inositol in milk was 8% of that of glucose in the blood. When $(^3H)-myo-Inositol$ was injected, the specific radioactivity of myo-Inositol in milk was about 26% of that of blood six hours after injection.

우유중에 상당량 존재하는 myo-Inositol의 생성을 알아보기 위하여 3% SE-52를 충진시킨 gas-liquid chromatography에 의해 myo-Inositol의 정량을 행하고 이 myo-Inositol의 유래를 feeding 실험과 $(^{14}C)-glucose$와 (3H)-myo-Inositol을 쥐에 주사한 실험으로 알아 븐 결과 다음과 같은 결과를 얻었다. 1. 쥐우유를 G.L.C. 방법으로 분석하여 우유 100gm.당 61-91mg.의 myo-Inositol (free)을 얻었다. 2. Feeding 실험 결과 우유 myo-Inositol의 85%는 diet에서 흡수되었고 나머지는 mammary gland에서 합성된 것으로 나타났다. 3. $(^{14}C)-glucose$에서 $(^{14}C)-myo-Inositol$ 생성은 lactose의 생성과 비슷하게 한시간이내에 최고에 달하였다. 4. $(^3H)-myo-Inositol$을 lactating rat에 주사하여 실험한 결과 우유 myo-Inositol의 대부분은 혈액 myo-Inositol에서 유래되었다. $(^{14}C)-glucose$를 주사한 후 우유중에 나타난 myo-Inositol의 비방사능(比放射能)은 4시간 후에 혈액 glucose의 8%였다.