Question

35 y/o man with 3 yr history of enlarging nose, coarse facies, muscle weakness, increased hand/foot size. Large fleshy nose and prognathism on exam. High IGF-1 in serum. MRI shows pituitary adenoma. Morphologic analysis of the tumor shows a densely granulated somatotroph adenoma. Further studies show that the G alpha-s subunit of the tumor G proteins lack GTPase activity. The tumor cells most likely have an increased activity of which enzyme?

Answer 1

Adenylyl Cyclase

Step-by-step explanation:

The tumor cells most likely have an increased activity of enzyme Adenylyl cyclase.

Since the G alpha-S subunit lacks the GTPase activity, the GTP will not be hydrolized to GDP.As a result the activity of G protein or G subunit will not be inhibited. Thus their respective enzymes will remain active.

An increased activity of Gs Subunit will thus lead to increased activity of enzyme adenylyl cyclase.