Distribution and Morphology of Ghrelin-Immunopositive Cells in the Liver of the African Ostrich/ Distribucion y Morfologia de las Celulas Inmunopositivas a la Gregina en el Higado de Avestruz Africana

Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor, and has been found in the liver of multiple vertebrates. While ghrelin has been identified in the gastrointestinal tract of African ostrich chicks, little is known regarding its distribution in the liver of the African ostrich. In the present study, the distribution and morphological characteristics of ghrelin-immunopositive (ghrelin-ip) cells in the liver of the African ostrich were investigated using immunohistochemistry. Our results indicate that the liver is divided into two sections: the capsule and the parenchyma, which comprises hepatic lobules and the hepatic portal area. The hepatic lobules include the central vein, hepatocellular cord, and the hepatic sinusoid. The hepatocellular cord is composed of hepatocytes, and Macrophagocytus stellatus (Kupffer cells) as well as endothelial cells reside within the hepatic sinusoid. ghrelin-ip cells were detected among both the Macrophagocytus stellatus and endothelial cells of the hepatic sinusoid in the African ostrich liver. In contrast, no ghrelinip cells were located within the hepatocytes or the hepatic portal area. These results clearly demonstrated the presence of ghrelin-ip cells in the liver of the African ostrich. Therefore, ghrelin may have a physiological function in the liver of the African ostrich. KEY WORDS: African ostrich; Ghrelin; Liver; Immunohistochemistry. La ghrelina es el ligando endogeno para el receptor secretagogo de la hormona del crecimiento, y se ha encontrado en el higado de multiples vertebrados. A pesar que la ghrelina ha sido identificada en el tracto gastrointestinal de polluelos de avestruz africanas, poco se sabe sobre su distribucion en el higado de esta ave. En el presente estudio se investigo la distribucion y caracteristicas morfologicas de las celulas ghrelininmunopositivas (ghrelin-ip) en el higado del avestruz africana mediante inmunohistoquimica. Nuestros resultados indican que el higado se divide en dos secciones: la capsula y el parenquima, que comprende los lobulos hepaticos y el area portal hepatica. Los lobulos hepaticos incluyen la vena central, el cordon hepatocelular y el sinusoide hepatico. El cordon hepatocelular esta compuesto de hepatocitos y de Macrophagocytus stellatus (celulas de Kupffer) y las celulas endoteliales se localizan dentro del sinusoide hepatico. Fueron detectacas celulas ghrelin-ip entre los Macrophagocytus stellatus y las celulas endoteliales del sinusoide h