Study on ribonuclease activity in tissues of human colonorectal mucosa using synthetic substrate

Activity in normal mucosa, cancer tissue and inflammatory mucosa of ulcerative colitis

Abstract

Activity of ribonuclease (poly Case, poly Uase) in tissues of normal colonorectal mucosa, colonorectal cancer and ulcerative colitis (UC) was measured using synthetic substrates (poly C, poly U). In normal mucosa, poly Case tended to show a higher value in the rectum compared to the colon. In cancer tissue and inflammatory region of UC, poly Case activity decreased, and this activity in the inflammatory region of UC further decreased as the inflammation was intensified. This was considered due to a decrease of non-specific synthesis in cancer tissue and to a decrease of synthesis, acceleration of RNA metabolism and decrease of cells containing poly Case in inflammatory tissue. Poly Uase activity was not significantly different among the three tissues.
The above-described changes of poly Case activity strongly suggested that abnormal metabolism of nucleic acids was present in cancer or inflammatory tissue. It was also considered clinicopathologically that poly Case activity may be used as a histochemical indicator of inflammation.