Uric acid is formed by the breakdown of:

Correct Answer: A

Rationale: Uric acid is a product of purine (e.g., adenine, guanine) catabolism, not pyrimidines, glutamine, or urea.

Correct Answer: D

Rationale: Acetylcholine stimulates glucagon via vagal input; somatostatin inhibits, FFAs and α-agonists can stimulate, GABA has less direct effect.

Correct Answer: A

Rationale: Aldosterone is classified as a mineralocorticoid. It promotes conservation of water by acting on the kidneys to retain sodium in exchange for potassium, which is excreted in the urine.

Correct Answer: A

Rationale: Endocrine disorders are caused by an imbalance in the production of hormone or by an alteration in the body's ability to use the hormones produced. Primary endocrine dysfunction means that an endocrine gland is either oversecreting or undersecreting hormone(s). Tumor or hyperplasia of the endocrine gland may lead to hypersecretion. Infection, mechanical damage, or an autoimmune response may be an inflammatory response in a gland and lead to hyposecretion. Secondary endocrine dysfunction occurs from factors outside the gland itself. Medications, trauma, hormone therapy, and other factors may cause secondary dysfunction. Long periods of limited mobility do not cause endocrine disorders.

Correct Answer: A

Rationale: The production of thyroid hormones decreases with age, but the decrease is offset by a matching decrease in the body's breakdown of the hormone. Changes in thyroid hormone levels are not affected by calcium, phosphorus, or mineralocorticoid levels.