Date of Award


Document Type


Degree Name



Biological Sciences

First Advisor

Robert M. Dores, Ph.D.

Second Advisor

Joseph Angleson

Third Advisor

James E. Platt

Fourth Advisor

Keith Miller


Melanocortin Receptors, Xenopus tropicalis


The role of Melanocortin 2 Receptor (MC2R) in adrenal/interrenal glucocorticoid secretion has been well documented in many organisms. Studies in mammals have shown that in the adrenal gland two melanocortin receptors and two melanocortin receptor accessory proteins are expressed: MC2R, MC5R, MRAP, and MRAP2. The MRAPs have an opposite effect on the cell surface expression of MC2R and MC5R. In mammals, MRAP aids MC2R but inhibits MC5R cell surface expression. This thesis aims to explore the functional relationship between MC2R, MC5R, MRAP, and MRAP2 in Xenopus tropicalis to determine if the MRAPs have a similar effect on amphibian MC2R and MC5R when the receptors are stimulated with ACTH, or apha-MSH. Expression of these four genes in the frog interrenal was verified through RT-PCR. Then CHO-K1 cells were transfected with plasmid constructs containing X. tropicalis MC2R, MC5R, MRAP2, and a mouse MRAP, and stimulated with ACTH or alpha-MSH. Levels of receptor activation were measured using a CRE-luciferase reporter gene. The findings presented here indicate that in the frog the MRAPs do not have a negative effect on MC5R, since activation of MC5R was not inhibited in the presence of MRAPs. The sensitivity of MC5R for ACTH increased from an EC50 of 1.2 x 10-9 M to an EC50 of 8.7 x 10-11 M in the presence of MRAP (p50 of 1.3 x 10-10 M in the presence of MRAP2 (p

Publication Statement

Copyright is held by the author. User is responsible for all copyright compliance.


Received from ProQuest

Rights holder

Yesenia Garcia

File size

88 p.

File format





Biology, Cellular biology, Molecular biology