In the context of a glucagonoma, what effect does continuously secreted glucagon have on blood glucose levels?

In the case of a glucagonoma, which is a type of pancreatic neuroendocrine tumor that secretes excessive amounts of glucagon, the continuous secretion of glucagon leads to significant physiological effects on blood glucose levels. Glucagon is a hormone that primarily acts to increase blood glucose levels by promoting gluconeogenesis and glycogenolysis in the liver. When glucagon is secreted inappropriately and excessively as in glucagonoma, it results in high levels of glucose being released into the bloodstream, thus causing hyperglycemia.

This condition reflects the underlying pathology of glucagonoma, where the tumor's activity overwhelms the body's ability to maintain glucose homeostasis, leading to an increase in blood glucose levels. Therefore, the correct answer is that the continuously secreted glucagon from a glucagonoma increases blood glucose levels.