CHARACTERIZATION OF PITUITARY GROWTH HORMONE IN THE GREEN IGUANA (Iguana iguana).

Abstract

Event Abstract Back to Event CHARACTERIZATION OF PITUITARY GROWTH HORMONE IN THE GREEN IGUANA (Iguana iguana). Jose Avila-Mendoza1, Martha E. Carranza-Salas1, Maricela Luna1 and Carlos Arámburo1* 1 Universidad Nacional Autonoma de Mexico, Institute of Neurobiology, Dept. of Molecular and Cellular Neurobiology, Mexico Although growth hormone (GH) has been studied in many vertebrates, it is poorly characterized in reptiles, where its structure has been described only in a turtle, a crocodile and, more recently, a snake. Here we studied the morphology and ultrastructure of pituitary somatotrophs in the green iguana (gi, Order Squamata) and characterized the giGH structure, which allowed an evolutionary analysis. The green iguana pituitary is constituted by a pars distalis and a pars nervosa, divided by a pars intermedia which, in contrast to other reptiles, is more developed in this species. The cellular distribution of giGH was analyzed by in situ hybridization and immunohistochemistry, using a specific-riboprobe and an antibody against chicken GH, respectively. The somatotrophs were found mainly in the caudal region of the pars distalis. Electron micrographs showed that they are 6.5-10 µm cells containing a good amount of granules (250-300 nm) where giGH is stored. The pituitary giGH was purified by immunoaffinity chromatography using a heterologous immunosorbent prepared with a polyclonal anti-chicken GH (cGH) antibody. SDS-PAGE and Western blotting of the purified preparation showed a main monomeric giGH variant with an apparent MW of 26 kDa and a dimeric molecular variant of 52 kDa (under reducing conditions). Furthermore, giGH showed at least four charge variants (pIs between 6.2-7.4) by isoelectric focusing. Additionally, the cDNA of giGH was amplified by PCR and 3’ & 5’ RACE. The sequence obtained consisted of 1016 bp that encoded a pro-hormone of 218 aa, containing a signal peptide (27 aa) and the mature protein corresponding to 191 aa. An identity pattern of 81%, 82%, and 84% was obtained when giGH was compared with chicken, crocodile and turtle GHs, respectively. The phylogenetic analysis showed that giGH goes in a different branch than turtles and crocodiles, which are closer to birds. These findings will contribute to better understand the evolution of vertebrate GH. Acknowledgements Supported by CONACYT (F1-60296, 220839) and PAPIIT (IN205406-3, IN21029) grants Keywords: GH phylogeny, green iguana, Growth Hormone, Growth hormone variants, Pituitary, Somatotrophs, Squamata reptiles Conference: ISAREN 2011: 7th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology, Ann Arbor, United States, 11 Jul - 13 Jul, 2011. Presentation Type: Oral Presentation Topic: Abstracts Citation: Avila-Mendoza J, Carranza-Salas ME, Luna M and Arámburo C (2011). CHARACTERIZATION OF PITUITARY GROWTH HORMONE IN THE GREEN IGUANA (Iguana iguana).. Front. Endocrinol. Conference Abstract: ISAREN 2011: 7th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology. doi: 10.3389/conf.fendo.2011.03.00001 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Dr. Carlos Arámburo, Universidad Nacional Autonoma de Mexico, Institute of Neurobiology, Dept. of Molecular and Cellular Neurobiology, Queretaro, Queretaro, 76230, Mexico, aramburo@unam.mx Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract Supplemental Data The Authors in Frontiers Jose Avila-Mendoza Martha E Carranza-Salas Maricela Luna Carlos Arámburo Google Jose Avila-Mendoza Martha E Carranza-Salas Maricela Luna Carlos Arámburo Google Scholar Jose Avila-Mendoza Martha E Carranza-Salas Maricela Luna Carlos Arámburo PubMed Jose Avila-Mendoza Martha E Carranza-Salas Maricela Luna Carlos Arámburo Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.