Expression of Melanocortin Receptor 2 Involved in the Stress Response Pathway in Different Tissues of Broad-snouted Caiman (Caiman latirostris)

MARÍA V. PARACHÚ MARCÓ; PABLO SIROSKI; HUGO H. ORTEGA; AYELÉN AMWEG

Skukuza

Congreso; 24th Crocodile Working Meeting; 2016

Crocodile Specialist Group of the Species Survival Commision of the UICN

The interaction between melanocortin and reproduction is associated with various processes related to metabolism, stress, immunity, and neuroendocrine signaling pathways. Melanocortin receptors (MCRs) are involved in a diverse number of physiological functions, including pigmentation, steroidogenesis, energy homeostasis, exocrine secretion, sexual function, analgesia and inflammation. There are five MCR subtypes (termed MC1R to MC5R) that each has a different melanocortin peptide and different patterns of tissue expression. While other receptors are promiscuous for different peptides, the melanocortin MC2 receptor (MC2R) is a specific receptor that mediates different tissue responses to ACTH. Their identification, sequencing and expression were previously analyzed in mammal (human, bovine, rabbits and rodents), avian (Gallus gallus), reptilian (Anolis carolinensis), and amphibian (Xenopus tropicalis) tissues; however, there are no reports regarding their detection in crocodilians. In order to identify the mRNA coding C. latirostris MC2R, we designed a set of primers from sequence alignments of phylogenetically related species obtained from NCBI. We detected MC2R mRNA expression in C. latirostris adrenal, gonad, liver, and spleen tissues by reverse transcription PCR (RT-PCR) and real time PCR. This study is the initial step to performing an evaluation of the reproductive impact of the ACTH pathway in steroid secretion and function in C. latirostris gonads. Since the neuroendocrine system is an essential component of reproduction, any response of this system to stress might influence reproductive success.