What is a likely effect of hyperthyroidism on glucose tolerance?

What is a likely effect of hyperthyroidism on glucose tolerance?

• A. Increased glucose tolerance
• B. No change in glucose tolerance
• C. Decreased glucose tolerance
• D. Variable with meals

Answer: (C)

Excess thyroid hormone accelerates almost all aspects of metabolism, including how the body handles glucose. In hyperthyroidism, the liver churns out more glucose through increased gluconeogenesis and glycogenolysis, the gut absorbs more glucose after meals, and insulin is cleared faster while tissues may become less sensitive to it. This combination raises blood glucose levels after eating and overall disrupts glucose regulation, which is why glucose tolerance is decreased. The other ideas don’t fit because the dominant effect of excess thyroid hormone is to worsen glucose handling, not improve it, and it isn’t a neutral or highly variable process.