Which of the following best describes the relationship of insulin to glucagon?
A) They work together to prepare the body to deal with stress.
B) Insulin stimulates the pancreas to secrete glucagon.
C) High levels of insulin inhibit pancreatic secretion of glucagon.
D) They are antagonistic hormones.
E) Insulin is a steroid hormone; glucagon is a protein hormone.
D is the correct answer. They bring about opposite effects.