Study of the effect of insulinoma on the levels of insulin and glucagon in different rat tissues

ABSTRACT

The insulinoma tumour was induced by x-irradiation in white male rats. Small fragments of the original tumour were implanted into recepient rats. A group of normal rats were left as control. Plasma glucose levels were determined by glucose oxidase method in both groups tumour bearing rats and control rats. Plasma insulin and the insulin content of the pancreas, tumour, and fraction of gastrointestinal tract extracts were measured by RIA in both groups. Renal, pancreatic and tumour extracts glucagon was measured similarly. Analysis of the weights of the animals and tissues revealed no significant differences between the control and tumour bearing rats. Hyperinsulinemia and hypoglycaemia were observed in the insulinoma bearing rats. Tumour bearing rats showed low concentrations of insulin in the pancreas, and duodenum along with low concentration of glucagon in pancreas. However, control group displayed low concentration of both insulin and glucagon in the colon and ileum respectively. Atrophy of A and B cells of the pancreas of the tumour bearing rats were observed. Measurement of insulin and glucagon in the pancreas revealed significantly lower concentration in the control rats