Impairment of insulin secretion in pancreatic islets isolated from Walker 256 tumor-bearing rats

Pancreatic islets isolated from Walker 256 tumor-bearing rats exhibit reduced insulin secretion as compared to control rats. Microscopy reveals that tumor-bearing and control rats have highly similar structural features. The islets from tumor-bearing rats show markedly reduced 45Ca2+ fractional outflow rate due to impaired voltage-dependent calcium channels. Perifusion experiments reveal that the reduction in 45Ca2+ fractional outflow is caused by phospholipase C in the islets, which reduce rats response to calcium.