Final answer:
A β-cell tumor, or insulinoma, causes severe hypoglycemia due to overproduction of insulin. It leads to symptoms like sweating, tremors, and fainting, which can be treated with glucose injections or oral sugar. This differs from diabetes mellitus, where high blood sugar levels occur.
Step-by-step explanation:
A β-cell tumor (insulinoma) would cause severe hypoglycemia. Insulinomas are tumors of the β-cells of the pancreas that overproduce insulin. This condition is known as hyperinsulinism and leads to excessively low blood glucose levels, as insulin facilitates the uptake of glucose by cells. The most common symptoms of hypoglycemia include sweating, tremors, fainting attacks, muscle weakness, and potentially unconsciousness or death if left untreated. Treatment typically includes injecting glucose or by providing sugar orally. Hypoglycemia stands in contrast to diabetes mellitus, which is a condition caused by the destruction or dysfunction of β-cells or cellular resistance to insulin, leading to high levels of blood sugar or hyperglycemia.