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Insulin and glucagon receptors in Morris hepatomas of varying growth rates
Abstract:
The binding of both insulin and glucagon to receptors in plasma membranes from five hepatomas of varying growth rates was diminished when compared to plasma membranes from normal liver. Scatchard analyses of the binding data suggested that the decrease in glucagon binding was due to a decrease in binding capacity, whereas the decrease in insulin binding was due either to a decrease in binding affinity or to site-site interactions. The decreased binding of insulin, but not of glucagon, showed a significant correlation with increasing growth rate of the tumors. These data suggest, therefore, that decreased binding of insulin to receptors could be a feature of increasing growth rate in hepatomas.
Insights
Insulin and glucagon receptor binding is reduced in hepatomas compared to normal liver. Decreased insulin receptor binding correlates with tumor growth rate, suggesting a role in hepatoma progression.
Area of Science:
- Hepatocellular carcinoma research
- Endocrinology
- Molecular biology
Background:
- Hormone receptor function is crucial for cellular signaling.
- Alterations in receptor binding can impact disease progression, including cancer.
- Hepatomas exhibit dysregulated cellular growth and metabolism.
Purpose of the Study:
- To investigate insulin and glucagon receptor binding in hepatoma plasma membranes.
- To compare receptor binding in hepatomas with varying growth rates to normal liver.
- To determine the correlation between receptor binding and hepatoma growth rate.
Main Methods:
- Plasma membranes were isolated from five human hepatomas and normal liver tissue.
- Hormone receptor binding assays were performed for insulin and glucagon.
- Scatchard analysis was utilized to characterize binding kinetics (affinity and capacity).
Main Results:
- Both insulin and glucagon binding were diminished in hepatoma membranes versus normal liver.
- Glucagon binding decrease was attributed to reduced binding capacity.
- Insulin binding decrease was linked to reduced binding affinity or site-site interactions.
- Decreased insulin binding, not glucagon binding, significantly correlated with increased hepatoma growth rate.
Conclusions:
- Reduced insulin receptor binding is a potential characteristic of increasing hepatoma growth rate.
- These findings suggest a role for insulin signaling dysregulation in hepatoma progression.
- Further research into insulin receptor dynamics in liver cancer is warranted.