Flatt P R, DeSilva M G, Swanston-Flatt S K, Powell C J, Marks V
Department of Biochemistry, University of Surrey, Guildford.
J Endocrinol. 1988 Sep;118(3):429-37. doi: 10.1677/joe.0.1180429.
The effects of repeated s.c. transplantation of clonal insulin-secreting RINm5F cells in NEDH rats on tumour morphology, insulin-glucose homeostasis and the function of RINm5F cells re-established in culture were examined after maintenance in vivo for periods of up to 308 days. Transplantation of RINm5F cells for ten consecutive passages consistently produced a single encapsulated vascularized tumour associated with the development in recipient rats of hyperinsulinaemia, hypoglycaemia and eventual neuroglycopenic coma. At the tenth passage, tumour-bearing rats exhibited a markedly enhanced rate of insulin-stimulated glucose uptake by 19 days, with evidence of a large and variable insulin response to i.p. glucose. Survival was 22 +/- 2 days, and resected RINm5F cell tumours exhibited weak immunostaining for insulin in scattered cells, with strands of fibrous tissue separating clusters of tumour cells many of which had distinct polarity. There was no detectable immunostaining for glucagon, somatostatin or pancreatic polypeptide. The insulin content and insulin secretory output of RINm5F cells re-established in culture after 20, 146, 259 or 308 days propagation in vivo were generally enhanced compared with non-passaged RINm5F cells. The magnitude of the effect was not appreciably affected by the duration of maintenance in vivo, but it was critically dependent upon the subsequent period of culture in vitro. Thus, whereas 2-day cultured RINm5F cells from the eighth tumour passage exhibited a greater than 100-fold increment of insulin content and release, with enhanced secretory responsiveness to leucine, arginine, theophylline, K+ (25 mmol/l) or Ca2+ (7.6 mmol/l), RINm5F cells cultured for a further 19 days had almost completely lost the attributes resulting from 259 days of maintenance in vivo. The results indicate substantial enhancement of the functional capabilities of RINm5F cells in vivo, and suggest that the resulting tumours afford a novel model in NEDH rats of responsive trabecular-type insulinomas.
在NEDH大鼠体内维持长达308天之后，研究了克隆性胰岛素分泌RINm5F细胞反复皮下移植对肿瘤形态、胰岛素-葡萄糖稳态以及在培养中重新建立的RINm5F细胞功能的影响。连续传代十次移植RINm5F细胞始终产生单个有包膜的血管化肿瘤，同时受体大鼠出现高胰岛素血症、低血糖症并最终发展为神经低血糖昏迷。在第十代时，荷瘤大鼠在第19天时胰岛素刺激的葡萄糖摄取率显著提高，有证据表明对腹腔注射葡萄糖存在大且可变的胰岛素反应。存活时间为22±2天，切除的RINm5F细胞瘤在散在细胞中对胰岛素呈弱阳性免疫染色，纤维组织束将肿瘤细胞簇分开，其中许多细胞具有明显的极性。未检测到胰高血糖素、生长抑素或胰多肽的免疫染色。与未传代的RINm5F细胞相比，在体内传代20、146、259或308天后在培养中重新建立的RINm5F细胞的胰岛素含量和胰岛素分泌量通常会增加。该效应的大小不受体内维持时间的明显影响，但关键取决于随后的体外培养时间。因此，来自第八代肿瘤传代培养2天的RINm5F细胞胰岛素含量和释放增加了100倍以上，对亮氨酸、精氨酸、茶碱、钾离子（25 mmol/L）或钙离子（7.6 mmol/L）的分泌反应性增强，而再培养19天的RINm5F细胞几乎完全丧失了因体内维持259天而产生的特性。结果表明RINm5F细胞在体内的功能能力大幅增强，并提示所产生的肿瘤为NEDH大鼠反应性小梁型胰岛素瘤提供了一种新模型。
