백서 소장점막의 부위별 Angiotensin Converting Enzyme의 효소 특이활성도차이에 대한 유전적 조절기전에 관한 연구 = The Genetic Regulation in Regional Difference of Specific Activity of Rat Intestinal Angiotensin Converting Enzyme백서 소장점막의 부위별 Angiotensin Converting Enzyme의 효소 특이활성도차이에 대한 유전적 조절기전에 관한 연구

다국어 초록 (Multilingual Abstract)

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다국어 초록 (Multilingual Abstract)

Recent reports indicate that angiotensin converting enzyme (ACE) in intestinal mucosa may be involved in protein digestion in vivo. The specific activities of intestinal ACE show regional difference. We performed this experiment to define the level of genetic regulation determining the regional difference of ACE specific activities by the relationship between ACE specific activities and ACE mRNA levels. Small intestines of 3 Wistar rats were removed and divided into 3 segments of equal length. Mucosal homogenate and brush border membrane (BBM) were prepared from scraped mucosa and ACE specific activities were measured in both samples by fluorometric method. Total RNA was extracted by guanidinium thiocyanate and isolated by Cesium chloride,ultracentrifugation. Each 6 ug of isolated RNA was transferred to nitrocellulose membrane by dot and slot apparatus. Northern hybridization with radiolabeled ACE 5 cDNA of mouse was performed and ACE mRNA was detected by autoradiography. The means of ACE specific ar.tivities (uM/ug protein/min) in harnogenate and BBM of proximal intestines were 23.4+- 4.8, 286.3+-80.6, in those of middle intestines were 21.3+-2.0, 211.0+-78.8 and those of distal intestines were 8.2+-1.9, 76.4+-10.7. The means of relative amounts of ACE mRNA in proximal, middle and distal intestines were 75%, 96% and 10% respectively. In linear regression analysis between ACE specific activities of BBM and relative amounts of ACE mRNA, R-value was 0.60 (p<0.05). We concluded that transcription was considered as the level of genetic regulation determining the regional difference of ACE specific activities.