A 20-year-old man with type 2 diabetes awakens at 3:00 am after 5 hours of sleep feeling queasy and light-headed. He tests his serum glucose and finds that it is 49 mg/dL. In response to his hypoglycemia, cortisol is secreted by the adrenal cortex and induces the synthesis of which of the following enzymes in the adrenal medulla?

Question

Quizplus · Accepted Answer

Cortisol induces the synthesis of phenylethanolamine N-methyltransferase (PNMT) in the adrenal medulla, which converts norepinephrine to epinephrine. Phenylethanolamine N-methyltransferase (PNMT) is an adrenal medullary enzyme whose activity is induced by cortisol. PNMT catalyzes the conversion of norepinephrine to epinephrine (see Chapter 31). The increased synthesis and release of epinephrine will trigger fatty acid release from adipose tissue and gluconeogenesis and glycogen breakdown in the liver. The released fatty acids are oxidized in the liver for ATP production necessary for gluconeogenesis to proceed.

A 20-Year-Old Man with Type 2 Diabetes Awakens at 3:00