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Biochemistry

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Insulin and PEPCK Regulation

BIOCHM-M6AQWF

Thiazolidinediones, also known as glitazones, are a class of drugs used to treat Type II diabetes. All thiazolidinediones have the same functional group, shown below, but vary in R-group composition. Elevated levels of free fatty acids (FFAs) seem to promote insulin resistance.

Thiazolidinediones enhance the production of (up-regulate) PEPCK (phosphoenolpyruvate carboxykinase) in adipose tissue in order to promote insulin sensitivity. PEPCK is the enzyme responsible for converting oxaloacetate into phosphoenolpyruvate.

Which of the following statements help explain why increased concentration of PEPCK leads to lower levels of FFAs?

Select ALL that apply.

Vaccinationist. "Thiazolidinedione." Wikipedia. Wikimedia Foundation, 28 Nov. 2015. Web. 16 Mar. 2016.

A

Increased PEPCK concentration leads to increased glucose levels; therefore, fewer FFAs are needed to provide energy to the adipose cells.

B

Increased PEPCK concentration ultimately leads to an increase in triacylglyceride (TAG) synthesis, reducing the amount of FFAs as the fatty acids will be incorporated into TAGs and no longer 'free'.

C

Increased PEPCK concentration promotes the formation of glycerol which can be transported to the liver and used as fuel.

D

Increased PEPCK concentration promotes the formation of the glycerol which is incorporated as the backbone of triacylglycerides (TAGs).

E

PEPCK is an allosteric effector of the insulin receptor.