Responsiveness of the hamster pancreatic cancer to treatment with microcapsules of D-Trp-6-LH-RH and somatostatin analog RC-160. Histological evidence of improvement.
The effect of treatment with D-Trp-6-LH-RH, an agonist of luteinizing hormone-releasing hormone (LHRH), and somatostatin analog RC-160 was studied in male Syrian hamsters with N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic carcinoma. The peptides were administered periodically in long-acting microcapsule formulations designed to release controlled doses and maintain continuous blood levels of these analogs. The treatment lasted 60 d. Eighteen wk after administration of BOP, 80% of the animals developed ductal pancreatic adenocarcinomas, typically in multinodular form. Treatment with D-Trp-6-LH-RH resulted in a significant decrease in the tumorous pancreatic weight, and, in 35% of the specimens, changes indicative of histological regression were seen. Similarly, regressive alterations in the tumorous epithelium could be observed in 28% of the tumors in the RC-160 treated group. This regression was not accompanied by accumulation of lymphoid cells and only the epithelial components of the tumors were involved. These data indicate that the analogs D-Trp-6-LH-RH and RC-160 exert antitumoral effects on the experimentally-induced pancreatic cancer. It is unlikely that immunological mechanisms are involved in this response. These inhibitory effects on tumor growth could be mediated by creating a state of sex hormone deprivation of D-Trp-6-LH-RH and by inhibition of the release and/or action of gastrointestinal hormones and growth factors by the somatostatin analog RC-160.
Zalatnai
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A
Veterans Administration Medical Center, New Orleans, LA 70146.
Schally
A V
AV
D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002214:Capsules; D006224:Cricetinae; D004848:Epithelium / Q000473:pathology; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000627:therapeutic use; D008297:Male; D008647:Mesocricetus; D009602:Nitrosamines; D010179:Pancreas / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D017329:Triptorelin Pamoate
D000970:Antineoplastic Agents; D002214:Capsules; D009602:Nitrosamines; D017329:Triptorelin Pamoate; C051458:vapreotide; D007987:Gonadotropin-Releasing Hormone; D013004:Somatostatin; C013622:nitrosobis(2-oxopropyl)amine