A patient with a pituitary tumor develops chronically elevated growth hormone (GH) levels. What distinguishes the GH feedback loop's response to this tumor from the loop's normal function?

💡 Explanation

The pituitary tumor autonomously secretes GH, bypassing normal regulatory controls. Because the elevated GH stimulates IGF-1, which normally inhibits GHRH release from the hypothalamus, chronic GH excess leads to downregulation of hypothalamic GHRH receptors; therefore, the response is reduced sensitivity, rather than normal feedback inhibition.

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