phy1 - aimhigh

[ArchivalUser]

1. A patient with acromegaly is treated with a newly developed
growth hormone receptor antagonist (GHR
antagonist) that specifically blocks growth hormone
receptors.Which set of changes would likely be caused
by treatment with the GHR antagonist?
(IGF-1 = insulin-like growth factor or somatomedin C)
Growth
IGF-1 Hormone Bone
Production Secretion Growth
(A) ↑ ↑ ↓
(B) ↑ ↑ ↑
© ↓ ↓ ↔
(D) ↓ ↓ ↑
(E) ↓ ↑ ↓

[ArchivalUser]

c?

[ArchivalUser]

E is the correct answer

IGF decreases
GH increases
Bone growth decreases

[ArchivalUser]

A is the answer

[ArchivalUser]

1. The correct answer is E. GHR antagonist therapy represents
a novel mechanism of action in the medical management
of acromegaly. Growth hormone (GH) acts by
binding to the growth hormone receptor (GHR). GH
stimulation of its receptor leads to production of insulinlike
growth factor-1 (IGF-1, also called somatomedin C),
which is responsible for nearly all the growth effects of
GH. Therefore, GHR antagonist therapy decreases the
production of IGF-1 and reduces bone growth. GH is also
a stress hormone that acts by increasing lipolysis. This
action would also be blocked by the antagonist. In general,
by blocking the peripheral actions of a hormone, an
antagonist reduces negative feedback and increases the
secretion of the hormone. Circulating levels would then
be expected to be elevated. Therefore, the end results of
GHR antagonist therapy are decreased IGF-1 production,
decreased bone growth, and increased GH secretion.

[ArchivalUser]

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