Symptoms of Zollinger-Ellison syndrome include which of the following?

Zollinger-Ellison syndrome is characterized by gastrin-secreting tumors, known as gastrinomas, which lead to excessive production of gastric acid (HCl) in the stomach. This hypersecretion of acid results in high levels of hydrochloric acid, contributing to symptoms such as recurrent peptic ulcers and abdominal pain. The overproduction of HCl is a direct result of the elevated gastrin levels from the tumors, making high HCl levels the hallmark symptom of this syndrome.

In contrast, the other symptoms listed do not directly align with the mechanisms or effects of Zollinger-Ellison syndrome. High blood pressure is not typically associated with this condition; rather, it involves acid secretion and its complications. Low digestive enzyme levels are not characteristic of Zollinger-Ellison syndrome since the primary issue is acidity rather than enzyme secretion. Additionally, increased body temperature does not directly relate to the syndrome; it is not a common symptom associated with increased gastric acid production. Therefore, the presence of high HCl levels is what defines the syndrome and is the correct answer.