HORMONAL-REGULATION OF ADENYLATE-CYCLASE ACTIVITY IN CIRCULATING LYMPHOCYTES AND ITS INTERRELATIONSHIP WITH HORMONE SENSITIVITY OF TUMOR-TISSUE IN COLORECTAL-CANCER PATIENTS

The purpose of this study was to investigate the peculiarities of horm onal regulation of adenylate cyclase (AC) of blood lymphocytes in colo rectal cancer patients and to compare these peculiarities with hormone sensitivity of AC of colorectal tumors and normal colonic mucosa. Bas al and stimulated lymphocyte AC activity was studied in 51 healthy per sons and 52 cancer patients(14 with colon cancer, 21 with rectal cance r and 17 with stomach cancer) aged 20-75 years. In 31 of 35 patients w ith colorectal cancer the AC activity was studied simultaneously in ly mphocytes, tumor tissue and normal colonic mucosa. To evaluate basal a nd stimulated AC activity the measurement of c-AMP (Amersham kits) for med in the presence of ATP regenerating system was used. Basal and by VIP, pentagastrin and sodium fluoride stimulated AC activity in lympho cytes of gastrointestinal cancer patients was lower than in lymphocyte s of healthy subjects of similar age. Stage dependence of the paramete rs under study was not found. There was a tendency for higher basal an d stimulated lymphocyte AC activity in colon cancer patients as compar ed to stomach and rectal cancer patients. In colorectal cancer patient s the peculiarities of lymphocyte AC reactions to stimulation were clo ser to those in tumor tissue but not to those in normal colonic mucosa . The reaction of lymphocyte AC to VIP and glucagon coincided more fre quently with tumor AC reactions to the same hormones in case of hormon e nonsensitive tumors. Thus, basal and stimulated lymphocyte AC activi ty in colorectal cancer patients was modified to some degree by tumor factors. Lymphocyte AC reactions to VIP and glucagon may be considered as indirect markers of hormone sensitivity of colonic tumors. Moreove r, the probability of discovery of hormone nonsensitive tumors by this way is more reliable than hormone sensitive ones.