Glucagon/Insulin AAMC Q SECTION BANK #83

[Neplina94]

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The question asks, infusion of which peptide hormone will most likely prevent brain injury in newborn infants exposed to high glucose levels during their fetal development?

My reasoning was " since they're exposed to high glucose levels, then they need insulin to reduce blood glucose concentration by promoting uptake of glucose into cells" The answer was glucagon. Why is my reasoning flawed?

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[smukke]

Break it down. I can't read the second half of that paragraph but I assume it says that they continue to have higher than normal levels of glucose and insulin after birth?

Why did they have high glucose during fetal development? Due to maternal blood supply. (from passage)
What happens at birth? Maternal blood supply stops. (from passage)
How quickly is the newborn's glucose supply exhausted? 70 min for serum, then have to switch to hepatic which is soon exhausted, then on to breakdown amino acids (from passage) - Sounds bad in a growing baby.
What counter acts insulin? Glucagon (from background knowledge)

Why do they have high insulin levels? Insulin doesn't cross placenta, so if fetus see high glucose it's pancreas undergoes hyperplasia and big things secrete more stuff (from background knowledge)