A Group of Investigators Is Studying the Regulation of Catecholamine

question 93

Multiple Choice

A group of investigators is studying the regulation of catecholamine synthesis in response to severe stress.  In the experiments, subject rats are randomly assigned to either an experimental or a control group.  The experimental rats undergo resection of the pituitary gland, and the control rats undergo craniotomy without pituitary resection.  The experimental animals are subsequently found to have decreased production of epinephrine by the adrenal medulla and cortisol from the adrenal cortex compared with the control animals.  Decreased activity of which of the following enzymes is most likely responsible for the lower epinephrine in the experimental animals?

• A)Catechol-O-methyl transferase
• B)Dopa decarboxylase
• C)Dopamine beta-hydroxylase
• D)Monoamine oxidase
• E)Phenylalanine hydroxylase
• F)Phenylethanolamine-N-methyltransferase
• G)Tyrosine hydroxylase

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Definitions:

Cyclopentanecarboxylic Acid

A cycloalkane derived carboxylic acid, with the carboxyl group attached to a five-membered ring.

Reagents

Substances or compounds used in chemical reactions to cause or analyze a chemical change.

Reaction

An action through which one or more starting materials, or reactants, are altered to yield one or more new substances, termed products.

Reagents

Components or substances employed in a system to provoke a chemical reaction or to determine if such a reaction happens.