Transplantable acinar cell carcinoma of the rat pancreas. Morphologic and biochemical characterization

An acinar cell carcinoma of the pancreas, which developed in a F-344 rat after long-term nafenopin administration, was serially transplanted into inbred weanling rats by subcutaneous and intraperitoneal routes. The transplantability rate was 95% or more by both routes. The tumor implants became palpable in 20 to 30 days after subcutaneous transplantation, increasing in size rapidly thereafter during the next 25 to 30 days. In intraperitoneal recipients the abdomen was markedly distended within 1 month. No metastases were observed in this series of transplantations. Amylase and lipase levels in serum and tumor homogenates increased with tumor size. Morphologically, only a few cells contained zymogen granules immediately after the appearance of a palpable tumor; at later intervals, however, these granules were observed in many tumor cells. Seventy-two hours after the surgical removal of tumors, the serum amylase and lipase levels returned to control values. This transplantable pancreatic acinar cell carcinoma can be dissociated into functionally viable single cells by a simplified enzyme digestion and divalent cation chelation procedure. By light microscopic autoradiography, approximately 20% of these isolated cells were found to incorporate ³H-thymidine in vitro into nuclear DNA. The data presented in this paper should serve as a baseline for future studies on this transplanted tumor.